How to Find the Right Benadryl Dosage for Kids (and Use It Safely)

Spring is peak allergy season, with trees and plants finally flowering after the winter months. And while these buds are a welcome sight, your kids may struggle with some not-so-pleasant seasonal allergy symptoms. Benadryl (diphenhydramine) can relieve a child's allergy symptoms, but it can be extremely dangerous for younger children.

Read on for everything parents need to know about Benadryl for kids, including determining the proper dose.

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, MD, a pediatrician at Stanford Children's Health with Peninsula Pediatric Medical Group.

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, MD, a pediatrician with Northwestern Medicine Huntley Hospital. "The antihistamine medicines block the receptors for histamines, thereby preventing their action and the symptoms."

Benadryl is a first-generation antihistamine. That means it was among the first antihistamines developed. Unlike newer medicines, first-generation antihistamines cause side effects like inducing sleep, drowsiness, impaired alertness, and difficulty concentrating. Even so, Benadryl is still more effective than newer antihistamines for treating certain allergy symptoms, like hives.

Risks of Giving a Toddler or Baby Benadryl

"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 Food and Drug Administration (FDA) released a warning in 2007 that children under 2 should not be given antihistamines, as they can cause life-threatening side effects.

Side effects of Benadryl in babies and toddlers may include the following:

• Convulsions
• Rapid heart rates
• Decreased levels of consciousness

The warning was issued after an estimated 1,519 children younger than 2 were treated in US 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, deaths have been associated with Benadryl overdoses in children due to improper dosing.

Even in older kids, improper dosing can have fatal consequences. In 2020, the FDA warned parents about reported heart problems, seizures, coma, and death in teens participating in a viral social media trend of consuming large amounts of Benadryl.

How to Find the Right Benadryl Dosage for Kids

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

When determining the appropriate dosage for your child, it's important to note how often it's safe to give your child the medication. The AAP guidelines allow for giving the medicine every six hours (as needed) and warn parents not to give more than four doses in 24 hours.

Side Effects of Benadryl Parents Should Know

Though Benadryl is generally considered safe for kids 2 years and older when given in the correct dose for their weight, there are side effects and contraindications to be aware of. Benadryl can cause the following side effects:

• Dry mouth
• Drowsiness
• Dizziness
• Nausea and vomiting
• Loss of appetite
• Constipation
• Worsening chest congestion
• Headache
• Weakness
• Hyperactivity in children
• Nervousness

"[Benadryl] should be used with caution in children who are on other medications that cause drowsiness and in children with asthma," says Dr. Tan. "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 use it only temporarily.

"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."

In fact, many allergists have started recommending Zyrtec because, as a second-generation antihistamine, it has fewer side effects and lasts longer than first-generation antihistamines like Benadryl, adds Dr. Tan.

Options like Zyrtec (cetirizine) and Claritin (loratadine) are likely safe for most children 2 and up, but parents should always check with a health care provider before using any new medications.

Using Benadryl as a Sleep Aid for Kids

Experts stress that Benadryl should 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.

Benadryl is known to cause drowsiness, which is why many think that it can be a safe sleep aid: If it's safe to use for allergies, why wouldn't it be safe for sleep?

It turns out that Benadryl affects REM sleep by keeping a person in a light sleep state and preventing them from entering deeper, more restful, and restorative stages of sleep. Researchers theorize that this lack of restorative sleep may explain the link between long-term Benadryl use and a higher risk of dementia.

Similarly, toddlers and babies who struggle to go to sleep or stay asleep should never be given Benadryl as a sleep aid. Instead, parents can look closer at their bedtime and naptime routines to find better ways to help their little ones catch some z's.