Diphenhydramine temporarily alleviates symptoms of the common cold, hay fever, or other upper respiratory allergies, such as sneezing, runny nose, irritated and watery eyes, etc.


Diphenhydramine hydrochloride



Biochem Pharma


25 mg


Out of Stock.


I. Introduction

A. Brief History of Diphenhydramine

Diphenhydramine, introduced by Dr. George Rieveschl in 1943, was a groundbreaking advancement in antihistamine treatment that made its mark in history. This compound effectively addressed reactions paving the way for subsequent antihistamines. In the 1940s, Diphenhydramine received FDA approval and gradually became a standard feature in numerous households and medical establishments.

B. Chemical Classification and Structure

Diphenhydramine is classified as an antihistamine in the ethanolamine group. In terms of its structure, it is composed of two benzene rings linked by a chain, which gives it a combination of properties that are both attracted to water and oil. This distinct dual structure allows it to efficiently cross the blood-brain barrier, which's not something that many medications can easily accomplish.

C. Overview of Uses and Applications

Diphenhydramine has been a medication since its creation. It serves not as an antihistamine but also offers various therapeutic benefits. These include relieving allergies and promoting sleep. In the following sections, we will explore these uses in depth.

II. Uses of Diphenhydramine

A. FDA-Approved Indications

The FDA acknowledges the use of diphenhydramine for purposes. These include reducing redness and itchiness in the eyes caused by conjunctivitis12, addressing skin rashes and hives associated with urticaria23, relieving a runny nose commonly associated with allergies 23, and acting as a sedative for occasional sleeplessness23Diphenhydramine is a first-generation antihistamine that blocks the effects of histamine, a chemical created by the immune system3.

1: HIGHLIGHTS OF PRESCRIBING INFORMATION TALVEY Biweekly (Every 2 Weeks … 2: Diphenhydramine Uses, Dosage & Side Effects - Drugs.com 3: Diphenhydramine: Uses, Side Effects, Dosages, Precautions - Verywell Health

B. Symptomatic Relief of Allergies

Diphenhydramine is a remedy for allergies. It works by blocking histamine, which is a substance released during allergic reactions, thus reducing symptoms such as sneezing, itching and watery eyes123Additionally, it acts quickly to provide relief, comforting those affected4.

1: Allergy Relief (Diphenhydramine) Oral: Uses, Side Effects … - WebMD 2: Benadryl Allergy - Uses, Side Effects, and More - WebMD 3: Diphenhydramine Uses, Dosage & Side Effects - Drugs.com 4: Benadryl (diphenhydramine): Dosage, side effects, uses, and more

C. Sleep Aid Applications

Due to its calming effects, diphenhydramine also serves as a sleep aid. It provides a refuge for those who occasionally struggle with insomnia, allowing them to achieve a restful night’s sleep12By slowing down the nervous system, it facilitates the process of falling asleep and enables individuals to regain control of their nights3However, diphenhydramine can also cause side effects and should not be taken as a treatment for chronic insomnia145.

1: Should You Take Benadryl for Sleep? | Sleep Foundation 2: Can diphenhydramine be used as a sleep aid? - Drugs.com 3: Diphenhydramine Uses, Dosage & Side Effects - Drugs.com 4: Using Diphenhydramine as a Sleep Aid Insomnia Treatment - Verywell Health 5: Sleep Aid (Diphenhydramine) Oral: Uses, Side Effects … - WebMD

D. Motion Sickness Management

Sometimes when we travel, we may experience a sensation called motion sickness. However, there is a solution to this problem: diphenhydramine. By using this medication, we can effectively prevent symptoms such as nausea, dizziness, and vomiting12. Its ability to reduce these effects allows travelers to enjoy their journeys with peace of mind and make them more enjoyable. However, diphenhydramine can also cause drowsiness and other side effects, so it should be used cautiously and as directed by a doctor12There may be other medications that are more effective or have fewer side effects for motion sickness, such as scopolamine3.

1: Diphenhydramine Uses, Dosage & Side Effects - Drugs.com 2: Diphenhydramine: MedlinePlus Drug Information 3: Treatment of Motion Sickness | AAFP

III. Off-Label Uses

A. Anxiety and Stress Reduction

Although not primarily intended for this purpose, diphenhydramine has been discovered to affect anxiety and stress. Its sedative properties help soothe frayed nerves and troubled minds, bringing a sense of tranquility1However, diphenhydramine is not a recommended treatment for anxiety, as it can also cause side effects such as drowsiness, dry mouth, blurred vision, and confusion12Some people may even experience increased anxiety or agitation after taking diphenhydramine2Therefore, diphenhydramine should only be used as directed by a doctor and for short-term relief of allergy or insomnia symptoms13. Some other medications and therapies are more effective and safer for treating anxiety disorders3.

: Can You Use Benadryl for Anxiety? - Verywell Mind 2: Can Benadryl Cause Anxiety? Side Effects and Precautions - Healthline 3: Is Benadryl Effective for Anxiety? - Healthline

B. Treatment of Extrapyramidal Symptoms

Extrapyramidal symptoms, which are commonly seen as side effects of medications, cause movement disorders such as akathisia, dystonia, parkinsonism, and tardive dyskinesia12. Due to its properties, Diphenhydramine provides relief by counteracting these symptoms and promoting a more balanced neuromotor function34Diphenhydramine is an antihistamine that blocks the effects of histamine, a chemical that can cause allergic reactions and affect the brain and nervous system35Diphenhydramine can help reduce the involuntary muscle contractions, restlessness, and tremors that are associated with extrapyramidal symptoms4However, diphenhydramine should only be used as prescribed by a doctor and for short-term treatment of extrapyramidal symptoms, as it can also cause side effects such as drowsiness, dry mouth, blurred vision, and confusion35There may be other medications that are more effective or have fewer side effects for extrapyramidal symptoms, such as anticholinergics or benzodiazepines2.

3: Diphenhydramine Oral: Uses, Side Effects, Interactions … - WebMD 5: Diphenhydramine Uses, Dosage & Side Effects - Drugs.com 1: Extrapyramidal Symptoms: What Causes Them and How to Stop Them - Healthline 4: Diphenhydramine: Uses, Side Effects, Dosages, Precautions - Verywell Health 2: Extrapyramidal Symptoms - StatPearls - NCBI Bookshelf

C. Migraine Prophylaxis

In some situations, diphenhydramine can be used as a treatment option for managing migraines. By blocking the release of histamine, known to trigger migraines, it offers relief1Diphenhydramine can help reduce the inflammation, nausea, and sensitivity to light and sound associated with migraines1However, diphenhydramine is not a first-line treatment for migraines, as there is a lack of evidence to support its effectiveness and safety23Diphenhydramine is usually used as an adjuvant therapy, meaning it is added to other medications to enhance their effects or reduce their side effects21Diphenhydramine can also cause side effects such as drowsiness, dry mouth, blurred vision, and confusion, which may worsen the symptoms of migraines or interfere with daily activities45Therefore, diphenhydramine should only be used for migraines under the guidance of a doctor and for short-term relief14There may be other medications that are more effective or have fewer side effects for migraines, such as triptans, NSAIDs, or antiemetics34.

2: Diphenhydramine for Acute Migraine - Full Text View - ClinicalTrials.gov 1: Benadryl For Migraine - 19 Important Questions and Answers 3: Acute Migraine Headache: Treatment Strategies | AAFP 4: Migraine - Diagnosis and treatment - Mayo Clinic 5: Benadryl Side Effects: What They Are and How to Manage Them - Healthline

IV. How Diphenhydramine Works

A. Mechanism of Action

Diphenhydramine works at a level by blocking the H1 receptor. In words, it stops histamine, a powerful trigger of allergy symptoms, from attaching to its receptors. This blockage helps prevent the chain reaction of reactions and relieves symptoms.

B. Pharmacokinetics and Pharmacodynamics

After consumption, Diphenhydramine quickly enters the bloodstream, and its maximum impact is noticeable within an hour. In the liver, it undergoes metabolism before being eliminated through the kidneys. On average, the drug remains in the system for about 2.5 to 8.3 hours, known as its life.

C. Impact on Central Nervous System

The sedative effects of Diphenhydramine are attributed to its influence on the nervous system (CNS). By reducing activity in the CNS, it induces feelings of sleepiness, which's why it is used as a sleep aid. However, being cautious is essential since this can also negatively affect abilities and motor skills.

V. Dosage and Administration

A. Standard Adult Dosing Guidelines

The usual recommended dose for grown-ups is between 25 and 50 mg, taken every 4 to 6 hours. However, it's essential not to exceed a total of 300 mg within 24 hours. It's crucial to follow these instructions to avoid any risk of taking too much.

B. Pediatric Dosing Guidelines

For kids between the ages of 6 and 12, giving them a dose of 12.5 to 25 mg every 4 to 6 hours is advisable. Make sure not to exceed a total of 150 mg in a day. If your child is under 6, it's essential to consult with a pediatrician before giving them any medication.

C. Adjustment for Specific Populations

People with liver or kidney problems may need to adjust their medication doses. Likewise, older patients might require changes in dosage because their bodies process drugs differently. These groups must have checkups and consult with their doctors.

D. Routes of Administration

Diphenhydramine offers options for administration. It can be taken orally in tablets, capsules, or liquid formulations. In urgent cases or depending on specific therapeutic requirements and the patient's age, it may also be administered via injection to provide relief. The choice of administration route is determined by factors such as the patient's needs and preferences, age, and the urgency of symptom relief.

VI. Composition

A. Active Ingredient

Diphenhydramine Hydrochloride is the active component found in diphenhydramine. It functions as a first-generation antihistamine working against histamine to alleviate allergic symptoms.

B. Inactive Ingredients and Excipients

The nonactive substances, also known as excipients, found in products may consist of; Cellulose compounds, dyes and colorants gelatin, magnesium stearate, and silicon dioxide. These ingredients do not possess any properties but shape the drug's form, add color, and make it easier to administer.

C. Available Formulations (Tablets, Liquid, Injection)

Diphenhydramine is produced in forms to cater to the varying requirements of patients. These include tablets and capsules, liquid syrup or elixir injectable solutions, topical creams and gels. This versatility enables healthcare providers to prescribe the suitable form based on the patient's condition, age, and personal preference.

VII. Storage

A. Ideal Storage Conditions

To ensure that diphenhydramine remains in its condition, it should be stored at room temperature avoiding high temperatures and moisture. Also, keep it from light and securely closed when not being used.

B. Shelf Life and Expiry Consideration

Like any medication, it is essential to avoid using diphenhydramine after its expiration date. This date ensures the product's quality and effectiveness. Using it beyond this point may lead to a decrease in efficacy and an increased risk of contamination.

C. Safety Measures for Disposal

When you have diphenhydramine that you no longer need or have expired, it's essential to dispose of it. Avoid flushing it down the toilet or drain. Instead, It is recommended contacting waste disposal agencies or speaking with a pharmacist for advice on safe and environmentally friendly ways to get rid of it.

VIII. Interaction

A. Drug-Drug Interactions

It's essential to be aware that diphenhydramine can interact with medications, potentially changing how they work. Some interactions to consider are; Other antihistamines or sedatives, Alcohol, Anticholinergic drugs Certain antidepressants. Before combining diphenhydramine with any other medications, it is crucial to consult with a healthcare professional.

B. Drug-Food Interactions

Although diphenhydramine usually doesn't interact much with food, taking it with meals is recommended to minimize any gastrointestinal side effects. Remember to follow the instructions on the packaging or those given by a healthcare professional.

C. Impact of Alcohol and Recreational Substances

Drinking alcohol or using recreational substances can worsen the sedative effects of diphenhydramine, which can significantly affect your ability to move and think. That's why avoiding these substances is recommended while taking this medication.

IX. Warning

A. Black Box Warnings

Currently, diphenhydramine does not carry any box warnings issued by the FDA. However, it is essential to read and follow all the signs mentioned on the packaging and follow healthcare professionals' guidance.

B. Potential for Drowsiness and Impaired Function

Diphenhydramine is well known for its sedating effects, which can help treat insomnia. However, it's essential for individuals to be aware that this medication might affect their ability to operate machinery or drive. It's crucial to gauge one's response to the drug before engaging in activities requiring mental alertness.

C. Allergic Reactions and Hypersensitivity

In some cases, people may experience a response to diphenhydramine itself. Indications of this can include a skin rash, swelling, dizziness, and trouble, with breathing. If these symptoms occur, it is essential to seek assistance right away.

X. Contraindication

A. Absolute Contraindications

Diphenhydramine should not be used in patients who are allergic to the drug or any of its components. Additionally, it is not recommended for use in newborns or premature babies due to the possibility of stimulating the nervous system and causing anticholinergic side effects.

B. Relative Contraindications

Conditions requiring caution include glaucoma, enlarged prostate, asthma, and gastrointestinal obstruction.

C. Contraindications with Specific Conditions

In people with liver or kidney problems, it is essential to adjust the dosage and closely monitor their condition because this medication is processed by the liver and eliminated through the kidneys.

XI. Careful Administration

A. Monitoring and Follow-up Recommendations

Patients prescribed diphenhydramine for long-term conditions should schedule follow-up appointments to check for any possible adverse effects and evaluate the ongoing necessity and effectiveness of the treatment.

B. Managing Missed Doses

Suppose you happen to miss a dose, try to take it soon as you can. However, if it's almost time for your dose, it's better to skip the missed one and continue with your regular dosing schedule. It's important not to double up on doses.

C. Avoiding Overuse and Dependency

Since diphenhydramine has sedating effects, avoiding excessive use is advisable to prevent potential dependency. It is essential to seek guidance and follow the instructions of a healthcare professional when using this medication.

XII. Important Precautions

A. Operating Heavy Machinery and Driving

Due to its sedating effects, diphenhydramine can significantly hinder a person's capacity to operate machinery or drive a car. Before participating in tasks, individuals must evaluate how this medication impacts their alertness and coordination.

B. Concurrent Use with Alcohol or CNS Depressants

Using diphenhydramine with alcohol or other substances affecting the central nervous system (CNS) can enhance its soothing properties. This may result in heightened drowsiness, impaired coordination, and potential respiratory depression. It is generally recommended to avoid using these substances while taking diphenhydramine.

XIII. Administration to Specific Populations

A. Administration to Elderly Patients

Dosage Adjustments; Older patients might be sensitive to the impacts of diphenhydramine, so it may be necessary to make adjustments to the dosage to minimize any potential side effects and risks. It is crucial to monitor for adverse effects, such as cognitive impairment, dizziness, or other adverse reactions, in this particular age group.

B. Administration to Pregnant Women and Nursing Mothers

Pregnancy Classification and Considerations; Diphenhydramine is classified as Category B during pregnancy, meaning there's no confirmed risk for humans. Nonetheless, it's advised to use it when necessary and under the guidance of a healthcare professional. Transfer to Breast Milk and Potential Concerns; It's important to note that diphenhydramine can pass into breast milk, potentially impacting a nursing baby. Therefore nursing mothers should consult with healthcare before taking this medication.

C. Administration to Children

Dosage Recommendations Based on Age: the dosage is usually determined by their weight when it comes to children. It's essential to follow the advice of a pediatrician when using this medication. Safety and Important Factors to Consider; It's crucial to exercise caution and strictly adhere to the recommended guidelines when giving diphenhydramine to children due to the risk of severe side effects, like hallucinations and seizures.

XIV. Over Dosage

A. Signs and Symptoms of Overdose

Signs of an overdose can include; feeling extremely drowsy, being agitated, having dilated pupils, and having dry skin. It is crucial to seek medical attention if there is a suspicion of an overdose.

B. Immediate Actions and Antidotes

In case of an overdose, seeking assistance from a poison control center or emergency room is essential. Medical professionals may consider using activated charcoal and intravenous fluids as part of the treatment. Physostigmine is the antidote recommended for diphenhydramine overdose.

C. Long-term Management of Overdose

Once the patient's condition has been stabilized, long-term management is expected to involve seeking evaluation and counseling. This helps in preventing any instances of intentional overdoses.

XV. Handling Precautions

A. Proper Handling and Storage

Store diphenhydramine at room temperature and keep it away from moisture and direct sunlight. It's best to keep the medication in its packaging until you're ready to use it.

B. Preventing Accidental Ingestion

Make sure to store diphenhydramine in a place where children cannot access it to avoid consumption, as it could lead to harm or even be fatal.

C. Safe Disposal Methods

You should make sure to dispose of any diphenhydramine that you don't use or that has expired. Check your regulations to find out the best way to do this. You might have options like medicine take-back programs or following safety guidelines for throwing it away in your household trash.

XVI. Common Side Effects

A. Frequently Reported Side Effects

Some common effects of diphenhydramine may include; Feeling Experiencing dizziness, and Having a dry mouth.

B. Managing Common Side Effects

Under the guidance of a healthcare professional, one can effectively manage side effects by adjusting the dosage timing or formulation of diphenhydramine.

C. Differentiating Between Serious and Mild Side Effects

Although feeling tired or experiencing dryness in the mouth is usually mild and quite common, it is essential to seek medical attention if you are experiencing a rapid heartbeat, severe dizziness, or difficulty urinating, as these symptoms can be more serious.

XVII. Conclusion

A. Summary of Key Takeaways

Diphenhydramine is a purpose medication primarily utilized as an antihistamine. However, it's crucial to exercise usage because of its sedative properties, possible side effects, and interactions with other substances.

B. Current Research and Future Directions

Ongoing research is being conducted to investigate the connection between diphenhydramine and dementia in elderly patients. Further studies in the future will help us gain an understanding of the advantages and disadvantages of using diphenhydramine over a long period.

C. Advice for Patients and Healthcare Professionals

Patients are advised to follow the instructions provided by their healthcare provider when using diphenhydramine and promptly notify them of any side effects. Healthcare professionals should stay alert for misuse or abuse of this widely accessible medication.

Customers also bought

Popular Products