Benadryl Dosage: How Much Diphenhydramine Can One Take?

Last Updated: July 20, 2020

Authored by Dr. Ahmed Zayed

Benadryl is a popular antihistamine that is often utilized to treat other conditions like insomnia as well. While the drug is generally safe and effective, it is essential to understand how Benadryl dosing works. Diphenhydramine dosage generally depends on the symptoms that will be treated with the medication, as well as the patient’s age. In some cases, the individual’s weight might be a contributing factor to the dosage as well. Benadryl dosage for children is also usually considerably lower than for adults. Overdosing on the medication can cause unpleasant side-effects that can, in some cases, be dangerous to a person’s health and require medical detoxification.

What Is Benadryl Adult Dose?

Benadryl dosage for adults is higher than that allowed to be administered to children as an adult’s body can handle a larger dose of the medication. The higher dose may also provide more effective relief of certain symptoms. It should, however, be noted that even though adults are allowed a higher dose of the medication, this does not mean that adults are free to take any diphenhydramine HCL dosage. Precaution is noted due to an increased risk of diphenhydramine side-effects when the dosage limitations for certain conditions and symptoms are exceeded.
Close up view of female doctor and a patient discussing Benadryl dosing.
Benadryl dosage for adults by weight is a model that is not often utilized, as weight is mostly taken into close account when administering the drug to a child. Still, if an adult weighs less than 100 pounds, weight is something that might have to be taken into account.
Benadryl administration based on weight among adults are as follows:

Adult Weight Tablet (Chewable) Capsule Dissolve Strip
55 lbs to 99 lbs 2x (25mg) 1x (25mg) 1x (25mg)
100 lbs and more 4x (50mg) 2x (50mg) 2x (50mg)

The adult dose of Benadryl should be administered with at least four to six hours in between each dosage.

What Is Benadryl Max Dose For Adults?

Due to the high risk of side-effects when taking too much of this medication, it is important for people to realize how much Benadryl is too much. While the maximum dose for adults is higher than the highest dosage that may be provided to a child, this does not mean an adult individual can take an exceptional amount of tablets to relieve their symptoms.
It is important also to consider how long does Benadryl take to work? The drug may not act very quickly, which might cause a person to consider taking a second dose too soon. This also causes an increased risk of more serious side-effects associated with the active ingredient diphenhydramine.
The appropriate adult Benadryl dose will depend on factors such as the condition that is being treated. The maximum dose also depends on the method of administration.

This dose can be taken in four-hour intervals. It is also not advised to take more than four doses of the medication in a single day. Furthermore, if a person finds that they need to use the medication consistently for more than four days per week, it is generally advised that the individual see a physician to obtain a drug that may be more effective for the treatment of their symptoms.
To avoid reaching a Benadryl overdose amount, a person should ensure they do not take more than 400mg of the drug for 24-hours.

Benadryl Adult Dosage For Extrapyramidal Reaction

Between 25mg and 50mg of the medication can be used to treat an extrapyramidal reaction. This dose can be taken up to four times each day. Parenteral administration of diphenhydramine can be provided in doses of up to 100mg at a time, with a maximum daily dose of 400mg. In such a case, the medication will be administered through IV or IM. Medical supervision is advised when using such high doses of the medication to assist in the treatment of an extrapyramidal reaction.

Benadryl Adult Dosage For Insomnia

The side-effects of the medication often sleepiness, which is why some people tend to opt for the drug to assist in the treatment of insomnia. When using the drug for insomnia, the advised dose depends on the type of diphenhydramine that is included in the capsule or tablet that a person will be taking.
Man sitting on bed and going to take Benadryl for insomnia
When using diphenhydramine Citrate, the advised dose is a 75mg oral pill before going to bed. In the case where diphenhydramine Hydrochloride is used instead, then the recommended dose is 50mg before going to bed.
It should be noted that it is generally not advised to continue using the drug for too long as an aid to assist with insomnia. If a person finds that their symptoms do not improve within two weeks while using this medication, they should consult with a physician.

Benadryl Adult Dosage For Motion Sickness

When used to assist in treating motion sickness, the advised dose is between 25mg and 50mg of diphenhydramine up to four times per day. The patient should take the first dose of up to 50mg before they start with the trip. The final dose should be taken when their trip comes to an end. There should, however, be at least a four-hour period between each dose.

Benadryl Adult Dosage For Allergic Rhinitis

The dose of this drug for treating allergic rhinitis depends on the type of active ingredient used. If a patient is using diphenhydramine Citrate, then a dose between 38mg and 75mg can be taken through oral administration of a capsule at a time. The maximum daily dose of diphenhydramine Citrate should not exceed 456mg. When using diphenhydramine Hydrochloride, the maximum daily dose should be limited to 300mg, and up to 50mg can be taken as a single dose.

Benadryl Adult Dosage For Cold Symptoms

It is advised that adults take up to 75mg of diphenhydramine Citrate at a time to assist in relieving symptoms associated with a cold. A lower dose is recommended when diphenhydramine Hydrochloride is used instead, with a recommendation of up to 50mg at a time. There should be at least a four-hour period between two doses of the medication. When provided with a parenteral administration of diphenhydramine, up to 100mg may be given to the patient at a time.

Benadryl Adult Dosage For Pruritus

In the case of Pruritus, a patient can opt for either diphenhydramine Citrate or diphenhydramine Hydrochloride. Between 38mg and 76mg can be administered as a single dose every four to six hours when the individual utilizes a drug that contains diphenhydramine Citrate. A 25mg to 50mg dose is advised when rather using a diphenhydramine Hydrochloride drug. Parenteral administration of the drug for the treatment of Pruritus may reach up to 100mg during a single dose, but should not exceed an administration rate of more than 25mg per minute.

Benadryl Adult Dosage For Urticaria

The use of the drug for treating Urticaria may be provided at doses of up to 76mg when using diphenhydramine Citrate or up to 50mg when using diphenhydramine Hydrochloride.
Diagnosis of Urticaria is written on a piece of white paper
This dosage should not be exceeded, and the person should wait four to six hours before taking another dose of the medication. The maximum daily dose for diphenhydramine Citrate is 456mg, and for diphenhydramine Hydrochloride is 300mg.

Benadryl Pediatric Dose

The use of this particular drug among children require careful administration and an appropriate dosage to ensure an overdose is not provided. Whether using Benadryl for hives, cold, or any other condition, it is crucial to follow the advised dosage instructions to assure the safety of the child that is being provided with this medication.

Here is a table of Benadryl dosage by weight for children:

Child’s Weight Liquid Tablet (Chewable) Capsule
22 lbs to 32 lbs 3ml serving (75mg) Not advisable Not advisable
33 lbs to 43 lbs 5ml serving (12.5mg) 1 (12.5mg) Not advisable
44 lbs to 54 lbs 7.5ml serving (18.75mg) 1 ½ (18.75mg) Not advisable
55 lbs to 99 lbs 10ml (25mg) 2 (25mg) 1 (25mg)
100 lbs or more 20ml (50mg) 4 (50mg) 2 (50mg)

Pediatric Dosage For Allergic Rhinitis

Child between the age of 6 and 12 can be provided with up to 38mg of diphenhydramine Citrate as a single dose or up to 6.25mg of Diphenhydramine Hydrochloride daily. When the child is older than 12, they can be provided with up to 76mg of diphenhydramine Citrate of up to 25mg of Diphenhydramine Hydrochloride in four-hour periods.

Pediatric Dosage For Cold Symptoms

Up to 38mg of Diphenhydramine Citrate can be provided or 25mg of Diphenhydramine Hydrochloride for children between 6 and 12. Older children may be provided with up to 76mg of Diphenhydramine Citrate or up to 50mg of Diphenhydramine Hydrochloride.

Pediatric Dosage For Motion Sickness

For treating motion sickness in children, Diphenhydramine Citrate can be used with a dose of up to 38mg before the start of the trip in children up to 12 or up to 76mg if the child is older than 12.
Child is suffering from motion sickness in the vehicle
When using diphenhydramine Hydrochloride, the maximum dose for children under the age of 12 is 25mg, and for those over the age of 12, up to 50mg may be provided.

Pediatric Dosage For Insomnia

The drug should not be used for the treatment of insomnia in children under 12 years. Up to 76mg of diphenhydramine Citrate can be used in children over 12 and up to 50mg of Diphenhydramine Hydrochloride prior to going to bed.

Pediatric Dosage For Extrapyramidal Reaction

Up to 25mg can be provided to a child for a maximum of four times daily for the treatment of an extrapyramidal reaction.

Pediatric Dosage For Allergic Reaction

Up to 25mg of the drug can be used to help treat an allergic reaction in children. When using Benadryl by weight, up to five milligrams of the medication can be provided per one kilogram of body weight.

What Is Benadryl LD-50?

The LD-50 of Benadryl is considered to be around 500mg per one kilogram of body weight.

For example, individuals should be wary of Benadryl and alcohol death and related complications. When it comes to looking at how much Benadryl it would take to result in more severe side-effects, it is also crucial to ask a question like how long does Benadryl last in the system? When taking multiple doses in short periods, it could lead to overdose symptoms. If OD on Benadryl took place the patient is advised to seek treatment in rehabilitation facility.

Taking Benadryl Safely

Excessive use of the drug, whether looking to use Benadryl for sleep dosage or another purpose, can lead to serious side-effects. Some people may also think that Benadryl dose for allergic reaction is much higher, but even when such a reaction is experienced, adhering to the max dose instructions is crucial. There are other types of drugs that are used to assist in treating an acute allergic reaction. It is also important to consider potential complications when using Benadryl while pregnant.
woman taking a pill with a glass of water at home
Some people who use the drug may experience diphenhydramine withdrawal if they become dependent on the medication to help with sleep and other issues that the product can assist with. In cases where a dependency occurs, the individual may need to opt for professional treatment.

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Published on: June 5th, 2019

Updated on: July 20th, 2020

About Author

Dr. Ahmed Zayed

Dr. Ahmed Zayed is a Bachelor of Medicine and Surgery. He is graduated from the University of Alexandria, Egypt. Dr. Ahmed Zayed has a passion for writing medical and health care articles and focuses on providing engaging and trustworthy information to readers.


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