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How Long Does Diphenhydramine Stay in Your System?

Clinically Reviewed by: Charee Marquez, LMFT

Have you ever wondered how long diphenhydramine, the active ingredient in popular over-the-counter medications like Benadryl, stays in your system? Whether you’re using it to relieve allergy symptoms, as a sleep aid, or for other purposes, understanding its duration of action and potential risks is crucial. In this blog, we’ll explore the intricacies of diphenhydramine, from its sedative properties to its antihistamine effects, overdose symptoms, and more. Join us as we uncover the facts behind this commonly used medication and how it interacts with your body.

What is Diphenhydramine?

Diphenhydramine, a widely employed antihistamine, serves as a go-to remedy for individuals grappling with allergy symptoms. It is widely recognized as the active component in various over-the-counter (OTC) medications, with Benadryl being a prominent example. Beyond its primary role in allergy relief, diphenhydramine has carved a niche for itself as a commonly utilized sleep aid, owing to its notable sedative properties. This dual functionality makes diphenhydramine a versatile compound, addressing not only allergic reactions but also catering to individuals seeking assistance in managing sleep-related concerns. Let’s delve deeper into the multifaceted aspects of diphenhydramine, exploring its mechanisms, applications, and considerations for those incorporating it into their health and wellness routines. Compared to other antihistamines, diphenhydramine may offer distinct effectiveness and potential side effects, including a higher risk of drowsiness, which is worth considering for those using it alongside other antihistamines containing diphenhydramine to avoid overdose risks.


Diphenhydramine Brand Names

Here are some common brands of diphenhydramine:

  1. Benadryl: Benadryl is one of the most well-known brands of diphenhydramine. It is available in various forms, including tablets, capsules, liquid gels, and oral solutions.

  2. Diphenhist: Diphenhist is another brand of diphenhydramine available in different formulations, such as tablets and liquid.

  3. Dormin: Dormin is a brand of diphenhydramine marketed specifically as a sleep aid. It is available in tablet form.

  4. Unisom: Some formulations of Unisom contain diphenhydramine as the active ingredient. Unisom SleepTabs, for example, contain diphenhydramine and are used as a sleep aid.

Diphenhydramine Types

Diphenhydramine is primarily available in various formulations designed to address specific needs. Common types of diphenhydramine include:

  1. Oral Tablets or Capsules:

    • Standard Diphenhydramine: Used for allergy relief, sleep aid, or cold symptoms.
    • Diphenhydramine HCl: Commonly used for allergy symptoms and itching.
    • Diphenhydramine Citrate: Used for allergy symptoms and as a sleep aid.
  2. Liquid Formulations:

    • Diphenhydramine Elixir: Liquid form suitable for those who have difficulty swallowing pills.
    • Diphenhydramine Syrup: A flavored liquid version commonly used for pediatric purposes.
  3. Topical Preparations:

    • Diphenhydramine Cream/Gel: Applied to the skin for relief from itching, such as due to insect bites or rashes.
  4. Diphenhydramine Combinations:

    • Diphenhydramine with Pain Relievers: Some formulations combine diphenhydramine with pain relievers like acetaminophen for enhanced relief.
  5. Allergy and Cold Formulations:

    • Diphenhydramine with Decongestants: Combined with decongestants for relief from allergy or cold symptoms.
  6. Sleep Aids:

    • Over-the-counter Sleep Aids: Diphenhydramine is commonly included in various OTC sleep aids.

It’s important to note that while diphenhydramine can be effective for various purposes, it may cause drowsiness, and individuals should use it according to the recommended dosage and guidelines.

Diphenhydramine Onset and Duration

Diphenhydramine is an antihistamine commonly used to treat allergy symptoms, insomnia, and motion sickness. It can also have sedative effects and is sometimes used recreationally, though this is not recommended due to potential side effects and health risks.

The onset and duration of diphenhydramine effects can vary depending on factors like individual sensitivity, dosage, and whether it’s taken on an empty or full stomach. Here are general timelines for the onset and duration:

Onset of Action:

  • Oral Administration: When taken orally (as a tablet or liquid), diphenhydramine typically begins to take effect within 30 minutes to 1 hour.

Duration of Action:

  • Sedative Effects: The sedative effects of diphenhydramine usually last around 4 to 6 hours. This can lead to drowsiness, which is why it’s often included in over-the-counter sleep aids. Benadryl stays in the system and can be detectable in urine tests for several days after ingestion. The duration it remains in the body can be influenced by factors such as age, metabolism, organ function, and dosage.

  • Antihistamine Effects: The antihistamine effects, which help alleviate allergy symptoms, may last for up to 8 hours or more.


Diphenhydramine Uses as a Sleep Aid and More

Diphenhydramine has several medical uses, primarily due to its antihistamine properties and sedative effects. Here are common uses of diphenhydramine:

  1. Allergy Relief:

    • Diphenhydramine is frequently used to relieve symptoms associated with allergies, such as itching, sneezing, runny nose, and watery eyes. It works by blocking the effects of histamine, a natural substance released by the body in response to allergens.
  2. Insomnia Treatment:

    • Due to its sedative effects, diphenhydramine is used as a short-term treatment for insomnia. It can help induce drowsiness and promote sleep.
  3. Motion Sickness:

    • Diphenhydramine is sometimes used to prevent and treat motion sickness. It can help alleviate nausea and dizziness associated with motion.
  4. Anti-itching (Pruritus):

    • The antihistamine properties of diphenhydramine make it effective in reducing itching associated with various skin conditions, insect bites, or allergic reactions.
  5. Cough and Cold Relief:

    • Diphenhydramine is occasionally included in over-the-counter cough and cold medications for its ability to relieve symptoms such as a runny nose and sneezing.
  6. Anaphylaxis:

    • In emergency situations, diphenhydramine may be used as part of the treatment for anaphylaxis, a severe allergic reaction. However, it is not a substitute for epinephrine, which is the primary and immediate treatment for anaphylaxis.

How Does Diphenhydramine Work in the Brain and Body as an Antihistamine Medication?

Diphenhydramine is a first-generation antihistamine commonly used to treat allergy symptoms, itching, motion sickness, and as a sleep aid. Its primary mechanism of action involves blocking the effects of histamine, a neurotransmitter involved in allergic reactions, in the body. However, diphenhydramine also has significant effects on various other neurotransmitter systems in the brain and body, which contribute to its sedative and anticholinergic properties.

  1. Histamine Blockade: Diphenhydramine binds to and blocks histamine receptors in the body, particularly H1 receptors. By inhibiting the action of histamine, diphenhydramine reduces symptoms of allergic reactions, such as itching, sneezing, runny nose, and watery eyes.

  2. Sedation: Diphenhydramine has strong sedative effects, which make it useful as a sleep aid. This sedation occurs because diphenhydramine can cross the blood-brain barrier and bind to histamine receptors in the brain, leading to drowsiness and promoting sleep.

  3. Anticholinergic Effects: Diphenhydramine also exhibits anticholinergic activity by blocking the action of acetylcholine, another neurotransmitter in the brain. This can result in side effects such as dry mouth, blurred vision, constipation, urinary retention, and cognitive impairment, particularly in older adults.

  4. Alpha-Adrenergic Blockade: Diphenhydramine blocks alpha-adrenergic receptors, which can contribute to its sedative effects and may also help alleviate symptoms of motion sickness.

  5. Central Nervous System Depression: In addition to its effects on specific neurotransmitter systems, diphenhydramine can depress overall central nervous system activity, leading to a general slowing of brain function and producing sedation.

Overall, diphenhydramine’s actions on histamine receptors, as well as its effects on other neurotransmitter systems and CNS activity, contribute to its therapeutic effects as an antihistamine, sleep aid, and treatment for various conditions. However, its sedative properties and potential for anticholinergic side effects should be considered when using the medication, particularly in older adults or individuals with certain medical conditions.


Diphenhydramine Efficacy

Diphenhydramine, commonly known by the brand name Benadryl, is an antihistamine medication used to relieve symptoms of allergies, such as sneezing, itching, watery eyes, and runny nose. Additionally, it is often used as a sleep aid due to its sedating effects.

The efficacy of diphenhydramine varies depending on the intended use:

  1. Allergy Relief: Diphenhydramine is effective at relieving allergy symptoms, including itching, sneezing, and nasal congestion, by blocking the action of histamine, a substance in the body that causes allergic reactions.

  2. Sleep Aid: Diphenhydramine is also effective at inducing drowsiness and promoting sleep. Its sedating effects can help individuals fall asleep faster and stay asleep longer. However, it is important to note that diphenhydramine is not intended for long-term use as a sleep aid and should only be used occasionally to treat short-term sleep disturbances.

While diphenhydramine is generally considered effective for its intended uses, it is not without side effects. Common side effects of diphenhydramine include drowsiness, dizziness, dry mouth, blurred vision, constipation, and urinary retention. Additionally, long-term use of diphenhydramine as a sleep aid may lead to tolerance, dependence, and rebound insomnia when the medication is discontinued.

Diphenhydramine Side Effects

Short-Term Side Effects of Diphenhydramine:

  1. Drowsiness and Sedation:

  • Diphenhydramine is known for its sedative effects, often causing drowsiness shortly after consumption.

  1. Dry Mouth and Throat:

  • Anticholinergic effects may lead to dryness in the mouth and throat.

  1. Blurred Vision:

  • Temporary visual disturbances, including blurred vision or difficulty focusing.

  1. Constipation or Difficulty Urinating:

  • Anticholinergic properties can affect bowel movements and urinary function.

  1. Dizziness and Lightheadedness:

  • Some individuals may experience feelings of dizziness or lightheadedness.

  1. Cognitive Impairment:

  • Temporary cognitive effects, including confusion or impaired concentration.

  1. Gastrointestinal Distress:

  • Upset stomach, nausea, or other mild gastrointestinal symptoms.

Long-Term Side Effects of Diphenhydramine:

  1. Cognitive Impairment:

  • Prolonged use may contribute to persistent cognitive effects, especially in older adults.

  1. Increased Risk of Falls:

  • The sedative nature of diphenhydramine can elevate the risk of falls, particularly in the elderly.

  1. Tolerance:

  • Long-term use may lead to tolerance, requiring higher doses for the same effects.

  1. Dependence:

  • Although rare, prolonged use may result in physical dependence.

  1. Memory Issues:

  • Some studies suggest a potential association between long-term anticholinergic use and memory issues.

  1. Increased Risk in Older Adults:

  • Older adults may face an elevated risk of adverse effects, including cognitive decline and delirium.

  1. Interactions with Other Medications:

  • Long-term use may increase the risk of drug interactions, especially with other medications affecting the central nervous system.

  1. Withdrawal Symptoms:

  • Discontinuing diphenhydramine after long-term or overdose use may lead to withdrawal symptoms, emphasizing the need for proper detoxification and consultation with a healthcare professional to manage potential dependency and severe withdrawal effects.

It’s crucial to use diphenhydramine as directed, considering short-term relief for specific symptoms.


Diphenhydramine Storage and Disposal

When storing diphenhydramine, keep it in its original packaging, tightly sealed, and away from moisture, heat, and direct sunlight. Store it out of reach of children and pets, in a secure location, to prevent accidental ingestion. Ensure that the medication is stored at room temperature, and avoid storing it in the bathroom or kitchen, where humidity and temperature fluctuations can occur.

When disposing of diphenhydramine, follow these guidelines:

  1. Check the medication label or package insert for specific disposal instructions.
  2. Do not flush diphenhydramine down the toilet or pour it down the drain unless instructed to do so by the medication label or a healthcare professional.
  3. Consider using a medication take-back program or community pharmacy disposal program to safely dispose of expired or unused diphenhydramine.
  4. If a take-back program is not available, mix the medication with an undesirable substance such as dirt, cat litter, or coffee grounds, and place it in a sealed container or plastic bag before disposing of it in the household trash. Remove any personal information from the medication packaging before disposal.

By storing diphenhydramine properly and disposing of it safely, you can help prevent accidental ingestion, misuse, and environmental contamination.

How Long Does Diphenhydramine Stay in Your System?

Understanding a drug’s half-life is pivotal in comprehending how long it takes for a substance to be eliminated from the body. Diphenhydramine, a commonly used antihistamine, exhibits an average half-life ranging from 2 to 8 hours, offering insights into its gradual clearance from the system. Let’s unravel the intricate dynamics of diphenhydramine’s half-life, breaking down the process into distinct phases.

  • In the initial 2 to 8 hours post-administration, approximately 50% of the drug undergoes elimination. This marks the first phase of clearance, indicating a significant reduction in the drug’s concentration within the body.

  • As time progresses to the interval of 4 to 16 hours, a more substantial portion of diphenhydramine, approximately 75%, is eradicated from the system. This signifies a continued decline in the drug’s presence, with the body actively metabolizing and expelling the compound.

  • Extending the timeline to 6 to 24 hours, a noteworthy 87.5% of diphenhydramine is cleared. This signifies the latter stages of the drug’s elimination, with the body working diligently to metabolize and eliminate the residual presence of the antihistamine.

  • The progressive nature of diphenhydramine’s elimination process highlights the dynamic interplay between the drug and the body’s metabolic mechanisms. It’s crucial to recognize that individual variations, such as metabolism rates and overall health, can influence the precise timeline of diphenhydramine clearance.

For most individuals, diphenhydramine will be almost completely eliminated from the body within 1-2 days. However, various factors can influence how quickly the drug is metabolized, such as age, liver function, dosage, and more.

In the context of drug tests, it’s important to note that diphenhydramine can be detected for a certain period, potentially causing false positives for substances like opiates, methadone, and PCP. The detection of diphenhydramine in drug tests varies, influenced by factors such as its half-life, the individual’s metabolism, and the dosage taken. This underscores the need for awareness about the implications of diphenhydramine showing up on a drug test, including the average timeline for its presence and the potential for false positives.

How long will the effects of diphenhydramine last?

The effects of diphenhydramine typically last for 4 to 6 hours. However, individual factors such as dosage, metabolism, and tolerance can influence how long the effects are felt.

Does diphenhydramine show up on drug tests?

Diphenhydramine is not typically included in standard drug tests such as urine drug screens. However, it may be detected in specialized tests designed to specifically detect antihistamines or in cases where specific testing for diphenhydramine is requested.

Can diphenhydramine accumulate in the body with repeated use?

Yes, diphenhydramine can accumulate in the body with repeated use, especially in individuals with impaired liver or kidney function. This can prolong its effects and increase the risk of side effects or toxicity.

How long should I wait before driving or operating machinery after taking diphenhydramine?

It is recommended to wait at least 8 hours after taking diphenhydramine before driving or operating machinery, as the medication can cause drowsiness and impair cognitive function.

Does age affect how long diphenhydramine stays in the system?

Yes, age can affect the metabolism and elimination of diphenhydramine. Older adults may metabolize the drug more slowly, leading to a longer duration of action and increased risk of side effects.

Can other medications affect the elimination of diphenhydramine?

Yes, other medications that affect liver enzyme activity or renal function can influence the metabolism and elimination of diphenhydramine. It’s essential to inform your healthcare provider about all medications you are taking to avoid potential interactions.

What should I do if I experience prolonged or severe side effects from diphenhydramine?

If you experience prolonged or severe side effects from diphenhydramine, such as persistent drowsiness, confusion, rapid heart rate, or difficulty breathing, seek medical attention immediately. These symptoms may indicate an overdose or allergic reaction and require prompt evaluation and treatment.

Diphenhydramine Risks

Diphenhydramine, commonly known as Benadryl or other brand names, is generally considered safe when used as directed for short-term relief of allergy symptoms or as a sleep aid. However, like any medication, diphenhydramine carries certain risks and potential side effects, particularly when misused or overused. Here are some risks associated with diphenhydramine:

  1. Drowsiness and Sedation: Diphenhydramine is known for its sedative effects, which can cause drowsiness and impair cognitive and motor function. This can increase the risk of accidents, falls, and injuries, especially in older adults.

  2. Impaired Coordination: Diphenhydramine can affect coordination and reaction time, leading to reduced motor skills and increased risk of accidents, particularly when driving or operating machinery.

  3. Anticholinergic Effects: Diphenhydramine has anticholinergic properties, which means it can block the action of acetylcholine, a neurotransmitter involved in various bodily functions. Anticholinergic effects can include dry mouth, blurred vision, constipation, urinary retention, and confusion, especially in older adults.

  4. Cognitive Impairment: Long-term or high-dose use of diphenhydramine may impair cognitive function and memory, particularly in older adults. Chronic use has been associated with an increased risk of dementia and cognitive decline.

  5. Rebound Insomnia: When used as a sleep aid, diphenhydramine can sometimes lead to rebound insomnia, where the sleep problems worsen after discontinuing the medication. This can create a cycle of dependence on the medication for sleep.

  6. Drug Interactions: Diphenhydramine can interact with other medications, including sedatives, antidepressants, and anticholinergic drugs, leading to increased sedation and other adverse effects. It’s important to consult with a healthcare professional before using diphenhydramine if you are taking other medications.

  7. Allergic Reactions: While rare, some individuals may experience allergic reactions to diphenhydramine, including rash, itching, swelling, and difficulty breathing. Seek immediate medical attention if you experience any signs of an allergic reaction.

  8. Overdose: In cases of overdose, diphenhydramine can cause serious symptoms, including hallucinations, seizures, irregular heartbeat, coma, and death. Overdose can occur accidentally or intentionally and requires prompt medical attention.

Is Diphenhydramine Addictive?

Diphenhydramine is not typically considered addictive in the same way that substances with abuse potential, such as certain drugs or alcohol, are. However, it’s essential to note that prolonged use or misuse of diphenhydramine can lead to tolerance, where higher doses are needed to achieve the same effects. Additionally, abrupt discontinuation after long-term use may result in withdrawal-like symptoms, emphasizing the importance of using the medication as directed by a healthcare professional.

While physical dependence can occur with prolonged use, the potential for psychological dependence or addiction is generally low. Diphenhydramine is an antihistamine commonly used for its sedative properties to relieve symptoms such as allergy-related issues, insomnia, or motion sickness. It is crucial for individuals to follow recommended dosages and guidelines provided by healthcare professionals to minimize the risk of adverse effects and dependence. If there are concerns about the use of diphenhydramine, it’s advisable to consult with a healthcare provider for personalized guidance.

Diphenhydramine Overdose Symptoms and Risks

Yes, it is possible to overdose on diphenhydramine, the active ingredient in medications like Benadryl and others. An overdose of diphenhydramine can lead to serious symptoms and complications, including:

  1. Central Nervous System Depression: Diphenhydramine is a central nervous system depressant, meaning it slows down brain activity. In overdose situations, this can lead to symptoms such as drowsiness, confusion, agitation, hallucinations, and coma.

  2. Respiratory Depression: High doses of diphenhydramine can suppress respiratory function, leading to shallow or difficulty breathing. Severe respiratory depression can result in respiratory failure, which can be life-threatening.

  3. Cardiovascular Effects: Diphenhydramine overdose can cause changes in heart rate and blood pressure, leading to tachycardia (rapid heart rate), arrhythmias (irregular heart rhythms), and even cardiac arrest in severe cases.

  4. Seizures: Some individuals may experience seizures as a result of diphenhydramine overdose, particularly at very high doses or in cases of acute toxicity.

  5. Death: In extreme cases, diphenhydramine overdose can be fatal, especially if prompt medical treatment is not sought.

It’s important to note that the severity of symptoms and the risk of complications depend on factors such as the amount of diphenhydramine ingested, the individual’s age, weight, overall health, and whether other substances were consumed concurrently.

If you suspect a diphenhydramine overdose or encounter someone who may have overdosed on diphenhydramine, seek emergency medical attention immediately. Prompt medical treatment is essential to prevent serious complications and ensure the best possible outcome.

Alcohol Use and Diphendyramine

Combining alcohol with diphenhydramine (the active ingredient in medications like Benadryl) can potentiate the effects of both substances and increase the risk of adverse reactions. Here are some potential risks and considerations associated with mixing alcohol and diphenhydramine:

  1. Central Nervous System Depression: Both alcohol and diphenhydramine are central nervous system depressants, meaning they slow down brain activity. When taken together, they can intensify each other’s sedative effects, leading to increased drowsiness, confusion, impaired coordination, and slowed reaction times. This can impair judgment and motor skills, increasing the risk of accidents, falls, and injuries.

  2. Respiratory Depression: Combining alcohol and diphenhydramine can also suppress respiratory function, leading to shallow or difficulty breathing. Severe respiratory depression can result in respiratory failure, which can be life-threatening, especially in individuals with pre-existing respiratory conditions or at higher doses.

  3. Cardiovascular Effects: Both alcohol and diphenhydramine can affect heart rate and blood pressure. Mixing the two substances may increase the risk of changes in heart rate, irregular heart rhythms, and other cardiovascular complications, particularly in individuals with underlying heart conditions.

  4. Increased Sedation and Impairment: The combination of alcohol and diphenhydramine can result in profound sedation and cognitive impairment, making it unsafe to drive or operate machinery. The effects can be unpredictable and may vary depending on factors such as the dosage of each substance, individual tolerance, and metabolism.

  5. Memory and Cognitive Impairment: Both alcohol and diphenhydramine can impair memory and cognitive function, particularly when used in combination. This can lead to confusion, disorientation, and difficulty concentrating.

  6. Increased Risk of Overdose: Combining alcohol and diphenhydramine increases the risk of overdose, as the effects of each substance can mask the symptoms of overdose from the other. Overdose symptoms may include severe drowsiness, respiratory depression, loss of consciousness, and even death in severe cases.

Given these potential risks, it’s important to avoid mixing alcohol with diphenhydramine or any other medications without consulting a healthcare professional. If you have questions or concerns about using alcohol or diphenhydramine, speak with your doctor or pharmacist for personalized advice and guidance. It’s always safest to use medications and alcohol responsibly and as directed.


Pregnancy and Diphenhydramine

During pregnancy, it’s essential to exercise caution with medications, including diphenhydramine (the active ingredient in medications like Benadryl). While diphenhydramine is generally considered safe for occasional use during pregnancy when used as directed, it’s essential to discuss its use with a healthcare provider, especially during the first trimester when fetal development is most critical.

Here are some considerations regarding the use of diphenhydramine during pregnancy:

  1. Risk of Birth Defects: Limited studies have been conducted on the use of diphenhydramine during pregnancy, particularly regarding its potential to cause birth defects. While there is currently no strong evidence to suggest that diphenhydramine increases the risk of birth defects in humans, it’s generally recommended to avoid unnecessary medication use during pregnancy, especially during the first trimester when the baby’s organs are developing.

  2. Risk of Drowsiness: Diphenhydramine is known for its sedative effects, which can cause drowsiness and impair cognitive and motor function. Pregnant individuals should be cautious when using diphenhydramine, especially if it may interfere with their ability to perform daily tasks safely.

  3. Treatment of Allergies and Insomnia: In some cases, diphenhydramine may be prescribed to pregnant individuals to relieve symptoms of allergies or insomnia. However, it’s essential to use diphenhydramine sparingly and under the guidance of a healthcare provider, weighing the potential benefits against the risks.

  4. Alternatives and Non-Drug Measures: Whenever possible, pregnant individuals are encouraged to explore non-drug measures to manage symptoms such as allergies or insomnia. This may include avoiding allergens, using saline nasal sprays, practicing relaxation techniques, maintaining good sleep hygiene, and sleeping in a comfortable environment.

  5. Consultation with Healthcare Provider: Pregnant individuals should always consult with their healthcare provider before taking any medications, including over-the-counter drugs like diphenhydramine. Healthcare providers can provide personalized advice based on individual health factors, medical history, and the specific circumstances of the pregnancy.

Ultimately, the decision to use diphenhydramine during pregnancy should be made in consultation with a healthcare provider, weighing the potential risks and benefits for both the mother and the developing baby. It’s essential to use medications responsibly and to follow healthcare provider recommendations to ensure the safest possible outcome for both mother and child.

Diphenhydramine Interaction with Medications

Diphenhydramine, like any medication, can interact with other drugs, potentially leading to adverse effects or reduced effectiveness of either medication. It’s essential to inform your healthcare provider about all medications, supplements, and herbal remedies you are taking before starting diphenhydramine. Here are some common medications that may interact with diphenhydramine:

  1. Central Nervous System Depressants: Diphenhydramine can potentiate the sedative effects of other CNS depressants, including alcohol, benzodiazepines, opioids, and certain antipsychotics. Combining these medications can increase the risk of drowsiness, dizziness, impaired coordination, and respiratory depression.

  2. Anticholinergic Drugs: Diphenhydramine exhibits anticholinergic effects, so combining it with other medications that have anticholinergic properties can increase the risk of anticholinergic side effects, such as dry mouth, blurred vision, constipation, urinary retention, and cognitive impairment. Examples of anticholinergic medications include tricyclic antidepressants, antipsychotics, and certain medications for overactive bladder.

  3. Monoamine Oxidase Inhibitors (MAOIs): Concurrent use of diphenhydramine with MAOIs can lead to hypertensive crisis, a severe and potentially life-threatening increase in blood pressure. MAOIs include medications such as phenelzine, tranylcypromine, and selegiline.

  4. Other Antihistamines: Combining diphenhydramine with other antihistamines, whether prescription or over-the-counter, can increase the risk of side effects such as drowsiness, dizziness, and impaired cognitive function.

  5. Medications Metabolized by Cytochrome P450 Enzymes: Diphenhydramine may inhibit or induce certain cytochrome P450 enzymes in the liver, affecting the metabolism of other medications. This can lead to changes in blood levels of these medications and potential interactions.

  6. Medications with QT Prolongation Risk: Diphenhydramine can prolong the QT interval on an electrocardiogram (ECG), so caution should be exercised when combining it with other medications that also have QT-prolonging effects, such as certain antibiotics, antipsychotics, and antiarrhythmic medications.

It’s essential to discuss any potential drug interactions with your healthcare provider before starting diphenhydramine or making changes to your medication regimen. They can provide guidance on managing interactions and adjusting your treatment plan as needed to ensure your safety and well-being.

Responsible Use of Diphenhydramine

Responsible use of diphenhydramine involves several key considerations to ensure its safe and effective use:

  1. Follow Recommended Dosage: Take diphenhydramine exactly as directed by your healthcare provider or as indicated on the packaging. Do not exceed the recommended dosage, and avoid taking it more frequently or for longer than recommended.

  2. Use for Intended Purposes: Diphenhydramine is primarily used to treat allergy symptoms, itching, motion sickness, and as a sleep aid. Use it only for its intended purposes and avoid using it to treat other conditions without consulting a healthcare professional.

  3. Be Aware of Side Effects: Familiarize yourself with the potential side effects of diphenhydramine, including drowsiness, dizziness, dry mouth, blurred vision, constipation, and urinary retention. If you experience any concerning side effects, contact your healthcare provider.

  4. Avoid Alcohol and Other Sedatives: Do not consume alcohol or other sedative medications while taking diphenhydramine, as this can increase the risk of excessive drowsiness, impaired coordination, and respiratory depression.

  5. Do Not Drive or Operate Machinery: Diphenhydramine can cause drowsiness and impair cognitive function, making it unsafe to drive or operate heavy machinery until you know how it affects you. Avoid engaging in activities that require alertness and coordination until you are sure of its effects.

  6. Use Caution in Older Adults: Older adults may be more sensitive to the sedative and anticholinergic effects of diphenhydramine, increasing their risk of falls, confusion, and other adverse effects. Use diphenhydramine cautiously in this population and under the guidance of a healthcare professional.

  7. Consult Your Healthcare Provider: If you have any questions or concerns about diphenhydramine or its use, consult your healthcare provider or pharmacist for guidance. They can provide personalized recommendations based on your medical history and individual needs.

  8. Store Safely: Keep diphenhydramine out of reach of children and pets, and store it in its original packaging at room temperature, away from moisture and heat.

By following these guidelines and using diphenhydramine responsibly, you can maximize its benefits while minimizing the risk of adverse effects or misuse. If you have any concerns about its use, do not hesitate to seek guidance from a healthcare professional.


Treatment Options for Diphenhydramine Addiction

Diphenhydramine abuse, a common yet often overlooked issue, can lead to severe drug addiction, marked by a dependency that is both psychological and physiological. The long-term effects of such abuse include heart problems, gastrointestinal issues, cognitive decline, memory loss, chronic depression, and anxiety. Moreover, the addictive nature of Benadryl, characterized by the development of tolerance, dependence, and alterations in neurotransmitters, underscores the importance of seeking professional treatment at a drug addiction treatment center tailored to the unique aspects of each individual’s addiction.

While Benadryl addiction can impact a person’s mind and body, several treatment options exist to overcome this problem. Based on the organization you choose, your doctor will treat Benadryl addiction in different ways, including:

Addressing Benadryl addiction typically involves a comprehensive approach that includes medical management, psychological support, and behavioral interventions. Here are some treatment options commonly used for Benadryl addiction:

  1. Medical Detoxification: For individuals with severe Benadryl dependence, medical detoxification may be necessary to manage withdrawal symptoms safely. A healthcare provider can gradually taper the dose of Benadryl to minimize withdrawal discomfort and monitor for any complications.

  2. Medication-Assisted Treatment (MAT): In some cases, medications may be prescribed to help manage withdrawal symptoms and cravings associated with Benadryl addiction. While there are no specific medications approved for Benadryl addiction, certain medications used for treating substance use disorders, such as clonidine or benzodiazepines for managing withdrawal symptoms, may be considered under medical supervision.

  3. Therapy and Counseling: Behavioral therapies, such as cognitive-behavioral therapy (CBT), motivational interviewing (MI), and contingency management, can help individuals address underlying issues contributing to Benadryl addiction, develop coping skills, and learn healthier ways of managing stress and cravings. Therapy sessions may be conducted individually or in group settings, depending on the individual’s needs and preferences.

  4. Support Groups: Participating in support groups, such as 12-step programs like Narcotics Anonymous (NA) or SMART Recovery, can provide peer support, encouragement, and accountability for individuals recovering from Benadryl addiction. These groups offer a safe and non-judgmental environment to share experiences, receive guidance, and learn from others who have overcome similar challenges.

  5. Education and Relapse Prevention: Education about the risks and consequences of Benadryl addiction, as well as strategies for relapse prevention, is essential for long-term recovery. Individuals can learn to identify triggers, develop coping strategies, and create a relapse prevention plan to maintain sobriety and avoid returning to problematic use.

  6. Lifestyle Changes: Making positive lifestyle changes, such as adopting a healthy diet, getting regular exercise, improving sleep hygiene, and engaging in meaningful activities, can support overall well-being and reduce the likelihood of relapse. Addressing co-occurring mental health issues, such as anxiety or depression, is also important for holistic recovery.

  7. Family and Social Support: Involving family members, friends, or other supportive individuals in the recovery process can provide additional encouragement and reinforcement. Open communication, setting boundaries, and building a strong support network can help individuals stay motivated and accountable during their recovery journey.

  8. Aftercare Planning: Developing a comprehensive aftercare plan is crucial for sustaining recovery beyond the initial treatment phase. This may include ongoing therapy, participation in support groups, regular medical check-ups, and continued engagement in healthy habits and activities to support long-term sobriety.

Inpatient, Partial Hospitalization Program (PHP), and Intensive Outpatient Program (IOP) are different levels of care offered in addiction treatment settings, each designed to meet varying needs and levels of support. Here’s an overview of each:

  1. Inpatient Treatment:

    • Inpatient treatment, also known as residential treatment, involves round-the-clock care and supervision in a specialized facility. It is typically recommended for individuals with severe substance use disorders or co-occurring mental health conditions who require a highly structured and supportive environment. Inpatient treatment provides intensive therapy, medical monitoring, medication management, and a range of therapeutic activities to address addiction and related issues.
  2. Partial Hospitalization Program (PHP):

    • Partial Hospitalization Programs offer structured treatment during the day, typically for several hours, several days a week. Participants return home in the evenings. PHPs provide intensive therapy, medication management, and support services tailored to the individual’s needs while allowing them to maintain connections with their families and communities. PHPs are suitable for individuals who require structured treatment but do not require 24-hour supervision or medical monitoring.
  3. Intensive Outpatient Program (IOP):

    • Intensive Outpatient Programs offer flexible treatment options that allow individuals to attend therapy sessions and participate in therapeutic activities while continuing to live at home and attend school or work. IOPs typically involve several hours of treatment per day, several days a week. They may include individual therapy, group therapy, family therapy, psychoeducation, and skills training. IOPs are suitable for individuals who require structured support and intensive therapy but do not require round-the-clock supervision or residential care.

The choice between inpatient, PHP, and IOP depends on factors such as the severity of addiction, co-occurring mental health conditions, level of functioning, support system, and treatment goals. A comprehensive assessment by a qualified addiction treatment professional can help determine the most appropriate level of care for an individual’s needs.

Does Insurance Cover Addiction Treatment?

Typically, yes. The coverage of addiction treatment by insurance can vary depending on the type of insurance plan, specific policy details, and the individual’s needs and circumstances. Here are key points to consider regarding insurance coverage for addiction treatment:

  1. Type of Insurance Plan:

    • Different types of insurance plans, such as private insurance, Medicaid, or Medicare, may have varying levels of coverage for addiction treatment.
  2. In-Network vs. Out-of-Network Providers:

    • Insurance plans often have a network of preferred providers. In-network addiction treatment facilities are generally covered at a higher rate than out-of-network providers. Checking if the facility is in-network can impact coverage.
  3. Verification of Benefits:

    • It is crucial to contact the insurance provider and verify the specific terms of coverage for addiction treatment. This includes checking details such as copayments, deductibles, and any out-of-pocket expenses.
  4. Medical Necessity and Preauthorization:

    • Insurance coverage for addiction treatment may be contingent on a determination of medical necessity. Preauthorization or approval from the insurance company may be required before entering a treatment program.
  5. Level of Care:

    • Different levels of addiction treatment, such as inpatient, outpatient, or intensive outpatient programs, may have different coverage considerations. Some insurance plans may cover certain levels of care more comprehensively.
  6. Length of Treatment:

    • Insurance coverage may be influenced by the length of the treatment program. Some plans may have limitations on the number of days covered, while others may provide more extensive coverage for longer durations.
  7. Parity Laws:

    • Mental Health Parity and Addiction Equity Act (MHPAEA) in the United States requires insurance plans to offer coverage for addiction services at levels comparable to medical and surgical coverage.
  8. Crisis or Emergency Situations:

    • In cases of immediate need or crisis, insurance plans may cover addiction treatment as part of emergency services. However, it is essential to follow up with the insurance provider for ongoing coverage considerations.
  9. Appeals Process:

    • If an insurance claim for addiction treatment is denied, individuals have the right to appeal the decision. The appeals process allows for a review of the denial, and successful appeals can result in coverage being granted.
  10. Out-of-Pocket Expenses:

    • Even with insurance coverage, individuals may still have out-of-pocket expenses, such as copayments or coinsurance. Understanding these costs is essential for financial planning.

Common Insurance Plans Used for Addiction and Mental Health Treatment

Common types of insurance plans used for addiction and mental health treatment include:

  1. Preferred Provider Organization (PPO):

    • PPO plans offer flexibility in choosing healthcare providers, allowing individuals to visit both in-network and out-of-network providers without a referral. PPO plans typically cover a portion of the cost for addiction and mental health rehab services, but out-of-pocket expenses may be higher when using out-of-network providers.
  2. Health Maintenance Organization (HMO):

    • HMO plans require individuals to choose a primary care physician (PCP) who coordinates their care and provides referrals to specialists, including addiction and mental health treatment providers. HMO plans often have lower out-of-pocket costs but may limit coverage to in-network providers, except in emergencies.
  3. Exclusive Provider Organization (EPO):

    • EPO plans combine aspects of both PPO and HMO plans, offering a network of preferred providers for individuals to choose from. While EPO plans do not require a PCP or referrals for specialists, coverage is typically limited to in-network providers, except in emergencies.
  4. Point of Service (POS):

    • POS plans offer individuals the option to receive care from both in-network and out-of-network providers. However, using out-of-network providers may result in higher out-of-pocket costs, and individuals may need a referral from their PCP to see specialists, including addiction and mental health treatment providers.

These insurance plans may vary in terms of coverage, network providers, cost-sharing requirements (e.g., copayments, coinsurance, deductibles), and authorization requirements for addiction and mental health rehab services. It’s essential for individuals to review their insurance plan documents, understand their coverage details, and verify network providers before seeking treatment. Additionally, individuals may need to obtain preauthorization or prior approval for certain rehab services to ensure coverage and minimize out-of-pocket expenses.


In conclusion, diphenhydramine, found in many over-the-counter medications, can have a significant impact on your body and health. From its sedative effects to its antihistamine properties, understanding how long diphenhydramine stays in your system and its potential side effects is essential for responsible use. Whether you’re seeking relief from allergy symptoms, using it as a sleep aid, or for other purposes, it’s crucial to follow recommended dosages and consult with a healthcare professional if you have any concerns. By staying informed and making informed choices, you can ensure safe and effective use of diphenhydramine and other medications.

FAQs on How Long Does Diphenhydramine Stay in Your System

Can factors such as liver or kidney function affect how long diphenhydramine stays in your system?

Yes, individuals with impaired liver or kidney function may metabolize and eliminate diphenhydramine more slowly than those with normal organ function. This can result in a longer duration of action and increased risk of side effects or toxicity. It’s essential for individuals with liver or kidney impairment to use diphenhydramine cautiously and under the guidance of a healthcare professional.

Does food intake affect the absorption or elimination of diphenhydramine?

Food intake can affect the absorption of diphenhydramine, particularly in terms of onset of action. Taking diphenhydramine with food may delay its absorption, leading to a slower onset of effects. However, food generally does not significantly impact the elimination of diphenhydramine from the body.

How long does diphenhydramine stay detectable in saliva, blood, urine, or hair?

Diphenhydramine can be detectable in saliva for up to 12-36 hours, in blood for up to 12 hours, and in urine for up to 1-4 days after ingestion, depending on various factors such as dosage, frequency of use, and individual metabolism. However, diphenhydramine is not typically tested for in standard hair drug tests.

Can diphenhydramine interact with alcohol or other substances to affect its elimination?

Yes, alcohol and other substances that affect liver function or central nervous system activity can potentially interact with diphenhydramine and influence its metabolism and elimination. Combining diphenhydramine with alcohol or other sedative drugs can increase the risk of excessive drowsiness, respiratory depression, and other adverse effects.

Are there any specific precautions to take when discontinuing diphenhydramine?

It’s important to gradually taper off diphenhydramine rather than abruptly discontinuing it, especially if it has been used regularly for an extended period. Abrupt cessation may lead to withdrawal symptoms such as rebound insomnia, anxiety, or agitation. It’s advisable to consult with a healthcare professional before discontinuing diphenhydramine to ensure a safe and smooth transition.

Seeking Treatment? We Can Help!

At California Prime Recovery, as an in-network provider we work with most insurance plans, such as:

If you or a loved one are struggling with mental health challenges or substance abuse, reach out to California Prime Recovery today. Our team of compassionate professionals is here to support your journey towards lasting well-being. Give us a call at 866-208-2390


Diphenhydramine is an antihistamine most often used to treat allergy symptoms such as sneezing, runny nose, itching, and watery eyes. It is also widely used as an over-the-counter sleep aid due to its sedative properties.

Yes, some common side effects of diphenhydramine include drowsiness, dizziness, constipation, stomach upset, blurred vision, and dry mouth/nose/throat. If any of these symptoms persist or worsen, it’s essential to consult with a healthcare professional.

It’s crucial to consult with a healthcare provider or pharmacist before combining diphenhydramine with other medications. Diphenhydramine can interact with several other drugs, especially alcohol, other antihistamines, and certain antidepressants.

While occasional use of diphenhydramine for allergies or sleeplessness is generally considered safe for most people, chronic daily use is not recommended without a doctor’s supervision. Prolonged use can lead to tolerance, meaning increased dosages are required for the same effect and potential dependency.

While diphenhydramine isn’t typically screened for in standard drug tests, it can, in rare cases, lead to false positives for benzodiazepines or PCP. If you’re taking diphenhydramine and are scheduled for a drug test, it’s advisable to inform the testing entity about all the medications and supplements you’re currently taking.

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