What's the Correct Benadryl Dosage for Children?

Benadryl can safely relieve allergy symptoms in children of the right age, but it should never be used as a sleep aid. Here are the safety precautions parents need to know.

box of children's benadryl on colored backgrounf
Photo: M.L. Gray/Fort Worth Star-Telegram/Tribune News Service/Getty Images

Spring is peak allergy season, with trees and plants finally flowering after frozen winter months. And while they're a welcome sight, your kids may be struggling with some not-so-pleasant allergy symptoms. Benadryl can relieve them, but it can be extremely dangerous when not given in proper doses to children of appropriate ages. Here's everything parents need to know.

What Is Benadryl?

"Diphenhydramine (commonly known by the brand name Benadryl) belongs to a class of medications called antihistamines that block the chemical histamine's activity in the respiratory tract, gastrointestinal tract, and the blood vessels," says Jeffrey Tan, M.D., pediatrician at Stanford Children's Health with Peninsula Pediatric Medical Group.

And it's these histamines that are responsible for allergy symptoms. "Histamines are naturally occurring substances in the body that can cause common allergy-type symptoms, such as hives, itching, and nasal congestion, or a cough related to allergies," says Kristi Redlich, M.D., a pediatrician with Northwestern Medicine Huntley Hospital. "The antihistamine medicines block the receptors for histamines, thereby preventing their action and the symptoms."

Benadryl Use in Babies and Toddlers

"Benadryl is not recommended for use in children under 2 years of age unless it's specifically directed by a doctor," says Dr. Redlich. The U.S. Food and Drug Administration released a warning in 2007 that children under 2 years of age should not be given antihistamines, as they can cause life threatening side effects, including convulsions, rapid heart rates, and decreased levels of consciousness.

The warning was issued after an estimated 1,519 children less than 2 years of age were treated in U.S. emergency departments for adverse events, including overdoses, associated with cough and cold medications from 2004 to 2005. "It is very important to follow dosing guidelines when giving Benadryl to kids. Giving incorrect doses can be quite dangerous, and even fatal," says Dr. Redlich.

Unfortunately, there have been many deaths associated with Benadryl overdoses in children due to improper dosing, including 7-month-old Abi Lobisch and an 8-month-old baby in Connecticut who was given a fatal dose as a sleep aid.

How to Know the Right Children's Benadryl Dose

Your child's weight will determine the proper and safe Benadryl dosage. "I like to have parents refer to a dosing chart, and we recommend this link from the American Academy of Pediatrics," says Dr. Redlich. "If there are any questions or a parent is not sure, I recommend they double check with their pediatrician prior to giving the medication."

And you should also be aware of other side effects Benadryl may cause in your children, as well as those with certain health conditions.

"Benadryl can cause drowsiness as well as mouth dryness, thickened sputum (mucus), and can also cause paradoxical excitation (hyperactivity) in some young children," says Dr. Tan. "It should be used with caution in children who are on other medications that cause drowsiness and in children with asthma. Although not common in children, parents should check with their physician before using Benadryl in kids with glaucoma, liver disease, or cardiovascular disease."

How to Avoid Overdose

It's OK to give kids of the appropriate age Benadryl to ease their allergy symptoms, but you should aim to keep its use temporary. "Benadryl is intended to mainly be used for short-term relief of allergy symptoms and it is not recommended to use it as a long-term allergy medication," says Dr. Redlich. "There are other types of antihistamines that would be preferable for long-term use because they have fewer significant side effects, like Claritin and Zyrtec." These are likely safe for most children 2 and up, but parents should check with their doctors before using any new medications.

Adds Dr. Tan, "In recent years allergists have started recommending cetirizine (brand name Zyrtec) as a second generation antihistamine more often due to longer duration of action (up to 24 hours) and much less sedation."

And again, Benadryl should also not be used for sleep aid or sedation. "Benadryl is never recommended to be used as a sleep aid for children, and it is also never recommended for use on long trips (plane or car rides) to keep kids calm," says Dr. Redlich.

The Bottom Line

"As with all prescription and non-prescription medication, Benadryl should only be used when needed with attention to proper dosing and possible side effects," says Dr. Tan.

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