What is Benadryl (Diphenhydramine)?

Benadryl is a common over-the-counter (OTC) medicine containing diphenhydramine as its active ingredient. It is used to relieve symptoms of allergic rhinitis (hay fever) and the common cold, such as runny nose, sneezing, and watery/itchy eyes. Benadryl is also used to provide relief from irritated or itchy skin caused by insect bites, hives, eczema, sunburn, and other medical conditions like motion sickness and insomnia. All in all, it has a great variety of uses.

While it is an effective drug, the risk with common over-the-counter medications like Benadryl is that people generally underestimate the potential harms associated with these medications. As a result, harmful adverse events may occur due to inappropriate treatment duration (taking the medication too long or too short) or inaccurate dosing (dose being too large or too small).

This article will discuss the appropriate doses and the risks of taking too much Benadryl.

What Forms Does Benadryl Come In and How Does It Work?

Benadryl is available in many different forms, including:

Oral (to be taken by mouth): tablets, chewable tablets, liquid-filled capsules, liqui-gels, and liquid solution
Topical (to be applied to the skin): creams, gels, and sprays

Some combination products contain diphenhydramine as the main ingredient, along with other ingredients. For example, Benadryl Allergy Plus Congestion for Sinus Pressure & Nasal Congestion Relief contains diphenhydramine, which is an antihistamine, and phenylephrine, which is a nasal decongestant.

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What Is the Correct Benadryl Dosage?

The correct Benadryl dosage depends on several factors. Among those factors is the condition you’re treating, your age, and the form of Benadryl you’re using. Your physician will advise you to take the lowest effective dose of Benadryl for the shortest possible time as best practice recommends.

Regarding effective Benadryl dosing, commonly used and recommended doses of Benadryl are as follows:

For Hay Fever, Allergies, and Common Cold Symptoms

The recommended dose for adults and children 12 years and older is 25 milligrams (mg) to 50 mg by mouth every 4 to 6 hours.
The recommended dose for children between the ages of 6-12 is 12.5 mg to 25 mg every 4 to 6 hours.
Children under the age of 6 should not take oral Benadryl without a doctor’s prescription.

For Itchy Skin From Insect Bites, Stings, Hives, Allergic Reactions, or Other Causes

Adults and children from age 2+ can use the topical form of Benadryl and apply gel, cream, or spray to the affected area up to 4 times daily unless the area is widespread and the oral form is advised by a healthcare professional.
Children under 2 years of age should use Benadryl topical products only if advised by a physician.

This is a general dosing guide. Some patients, for example, elderly patients, may need to take lower doses of this medication. If you have any specific questions about Benadryl dosages regarding your age and condition, you should consult your doctor or pharmacist.

Children’s Benadryl Dosage Chart

	Under 2 years old	2 to 5 years old	6 to 11 years old	12 years and older
Chewable Tablet (12.5 mg)	Don’t use	Ask a healthcare professional	Up to 2 tablets every 6 hours	2-4 chewable tablets (25 mg to 50 mg) every 4 to 6 hours
Tablet (25 mg)	Don’t use	Ask a healthcare professional	1 tablet every 4 to 6 hours	Up to 2 tablets at a time, up to 6 doses in 24 hours
Capsule (25 mg)	Don’t use	Ask a healthcare professional	1 tablet every 4 to 6 hours	Up to 2 tablets at a time, up to 6 doses in 24 hours
Liquid (12.5 mg per 5 mL)	Don’t use	Ask a healthcare professional	Up to 10ml every 6 hours	Directions not provided

Does Benadryl Require Dosage Adjustments for Specific Groups of People?

Yes, Benadryl may require dosage adjustments or special precautions for certain groups of people. Talk to your doctor before taking Benadryl if you have any of the following health conditions:

Liver or kidney disease
Glaucoma
Enlarged Prostate
Asthma or COPD
High blood pressure
Hyperthyroidism
Heart disease
Peptic ulcers
Seizures

Talk to your doctor about Benadryl if you are pregnant, plan to become pregnant, are breastfeeding, or are over age 65 to ensure safety and effectiveness.

Can I Take 2 Benadryl a Day?

Yes, you can take 2 Benadryl a day. Most adult formulations contain 25 mg to 50 mg of diphenhydramine hydrochloride (the main ingredient in Benadryl). You can take 1-2 tablets every 4 to 6 hours as long as it does not exceed 6 doses of Benadryl in a 24-hour period.

How Many Chewable Tablets of Benadryl Can You Take In a Day?

Children’s Benadryl Chewables contain 12.5 mg of diphenhydramine. People over the age of 12 years can take 2-4 chewable tablets (25 mg to 50 mg) every 4 to 6 hours. Children between 6 and 11 years old can take 1-2 chewable tablets (12.5 mg to 25 mg) every 4 to 6 hours. Children between 2 and 5 years old should take oral Benadryl chewables as directed by their doctor. Benadryl is not for children younger than 2 years old.

How Many Benadryl Can You Take at Once?

Adults can take up to 100 mg or 1-2 tablets of Benadryl at once. However, you should try to take the lowest possible dose for the shortest possible time to treat your symptoms.

What Is the Maximum Dosage of Benadryl?

The maximum dose of Benadryl for adults and children over 12 years of age is 300 mg per day. The maximum dose of Benadryl for children between the ages of 6 to 12 is 150 mg per day. Do not take more than 6 doses of oral Benadryl in 24 hours.

Benadryl topical products (creams, gels, sprays) should not be applied to the skin more than 4 times a day.

It is important to check all your other antihistamines and ensure that your other medications don’t contain the same active ingredient, i.e., diphenhydramine. The maximum dose mentioned above is the dose you can safely take from all products and different forms combined.

What Happens if You Miss a Dose of Benadryl?

If you are taking Benadryl on schedule and miss a dose, take it as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and go back to your regular dosing schedule. Do not take a double dose or extra medicine to make up for a missed dose.

What Happens if You Take Too Much Benadryl?

Scientists do not know a lot about the side effects of taking Benadryl long-term, but it has been linked to conditions such as:

Constipation
Weight gain
Blurred vision
Hallucinations
Memory problems, confusion, dementia
Restless legs syndrome
Depression and anxiety
Tolerance and dependence

Can You Overdose on Benadryl?

Yes, you can overdose on Benadryl. Signs and symptoms of a Benadryl overdose may include:

Confusion
Blurred vision
Dry mouth
Dizziness
Heart arrhythmia
Difficulty breathing
Irritability
Restlessness
Confusion
Hallucinations
Shock
Seizures
Coma
Death

What Should You Do if You Take Too Much Benadryl?

If you or someone you know may have overdosed on Benadryl, call 911 or seek care at the nearest emergency room without delay.

What Are Benadryl’s Side Effects?

The common side effects of Benadryl include:

Sleepiness
Dizziness
Headache
Dry mouth and dry eyes
Weakness.

If these symptoms are severe or do not go away after a few days, talk to your doctor or pharmacist.

Benadryl can also cause more serious side effects, such as:

Problems with cognition (thinking) and memory
Fast heartbeat (tachycardia)
Seizures

Contact your doctor if you experience these side effects and seek emergency medical care for serious side effects such as seizures.

What Are Benadryl Risks and Drug Interactions?

Benadryl can cause drowsiness, which can impair your ability to drive, operate heavy machinery, or do anything that requires focus. Falling asleep at the wheel can result in accidents, so follow your doctor’s instructions and do not drive while taking Benadryl until you know how this medication affects you.

If you are taking other drugs, talk to a healthcare provider before taking Benadryl to avoid serious drug interactions. For example, taking Benadryl with benzodiazepines (Valium, Xanax, Klonopin) can increase the risk of confusion, drowsiness, and delirium. Mixing Benadryl and alcohol can lead to drowsiness and sedation, increasing the risk of accidents and injuries.

How Many Days in a Row Can You Take Benadryl?

You should not use over-the-counter (OTC) Benadryl for longer than 7 days as treatment for cold and allergy symptoms. OTC Benadryl is intended for short-term use to provide temporary relief of allergy symptoms. If your symptoms do not improve after a week of Benadryl use, contact your doctor to obtain an accurate diagnosis and discuss alternative treatments.