Zyrtec And Benadryl: Can They Be Taken At The Same Time?

Last Updated: July 16, 2020

Authored by Sharon Levy, MD, MPH

Zyrtec and Benadryl are both antihistamines which are prescribed to relieve allergic symptoms, cold, flu, and other similar conditions. Benadryl (diphenhydramine) is a type of sedative antihistamine whereas Zyrtec (cetirizine) belongs to the class of non-sedative antihistamines. Both are available in the form of syrups, tablets, capsules, and topical creams. Read further to find out what are similar and different side effects of diphenhydramine vs. cetirizine? Can one take Zyrtec and Benadryl together? Which medicine is safer and more effective?

Is Zyrtec The Same As Benadryl?

Although both of them are antihistamine drugs, Benadryl medicine belongs to the first generation of antihistamines, which cause relatively more side effects and have sedative properties. Zyrtec, on the other hand, belongs to the second-generation non-sedating antihistamines. Their dosage and frequency of intake are also different.
man holding benadryl and zyrtec blisters

Can One Take Zyrtec And Benadryl Together?

A doctor might prescribe diphenhydramine to be taken a few hours after taking cetirizine for severe allergies.

Side Effect Of Benadryl And Zyrtec

Benadryl And Zyrtec Similar Side Effects

Some of the similar side effects of cetirizine and diphenhydramine described below:

  • Common side effects of both medicines include: drowsiness, tiredness, fatigue, dizziness, headache, constipation, dry mouth, and nausea.
  • Diphenhydramine weight gain is one of those side effects, which is also caused by cetirizine. Both medicines, when taken for the long-term, increase appetite in patients, which results in weight gain.
  • When taken in larger doses, both can cause hypotension, cardiac failure, hypertension, and chest pain.

Benadryl And Zyrtec Different Side Effects

The following table shows the difference between cetirizine and diphenhydramine in terms of side effects.

Diphenhydramine Cetirizine
Common side effects of benadryl include:

Difficulty in coordination
Blurred vision
Double vision

Common side effects of cetirizine:

Stomach Pain

Severe side effects of diphenhydramine include:

Difficulty urinating
Enlarged prostate

Severe side effects of cetirizine include:

Memory impairment

Benadryl VS. Zyrtec: Which Drug Is Safer And More Effective?

Which Drug Acts Faster: Cetirizine Or Diphenhydramine?

Cetirizine is a slow acting drug which needs to be taken only once a day. Diphenhydramine, on the other hand, starts to act faster, but Its effects also begin to wear off sooner, so it needs to be taken multiple times a day.

What Are The Dosage Requirements Of Zyrtec And Benadryl?

Liquid Benadryl dosage in children depends on their weight. It is available in 12.5mg/5ml concentration. Zyrtec liquid for children is available in the form of 5mg/5ml concentration. Its dosage also depends on the weight of the child.

hand holding benadryl and zyrtec pills

What Drugs Interact With Benadryl And Zyrtec?

Diphenhydramine and Cetirizine interactions with other drugs need to be considered when taking any one or both of these medicines. Diphenhydramine is shown to interact with a total of 830 drugs. These mostly include monoamine oxidase inhibitors (MAOIs), narcotic pain medicines, and muscle relaxers. Benadryl may also interact with the following:

  • Ibuprofen
  • Aspirin
  • Naproxen
  • Loratadine
  • Melatonin
  • Lisinopril
  • Metformin
  • Prednisone
  • Tramadol
  • Alprazolam
  • Sertraline

Cetirizine interacts with a total of 590 drugs including, but not limited to, the following medicines:

  • Loratadine
  • Fish oil
  • Flonase
  • Ibuprofen
  • Metformin
  • Omeprazole
  • Prednisone
  • Pseudoephedrine
  • Trazodone
  • Tylenol
  • Alprazolam

Alcohol also interacts with both Benadryl and Zyrtec. According to this study on the interactions of alcohol with various medicines, it was proved that taking it with diphenhydramine or cetirizine can lead to severe side effects. Diphenhydramine HCl and alcohol should never be taken together as it can lead to serious side effects.

Which One Is Safer To Take During Pregnancy?

Benadryl pregnancy category is classified as ‘B’. Category B medicine means that it is safe to be used in pregnancy. Similarly, Zyrtec is also classified as a Category B medicine and thus poses no danger to the mother or fetus. However, since cetirizine causes relatively lesser side effects as compared to diphenhydramine, it may be considered safer to be used in pregnancy.

Differences Between Zyrtec And Benadryl In Terms of Price

Zyrtec costs about $30 for 40 capsules whereas Benadryl costs about $12 for 24 capsules. If one calculates the daily dosage of both medicines, Zyrtec will cost $0.75 for a daily dose and Benadryl will cost $1.5 for a daily dose. This makes Zyrtec cheaper than Benadryl.

Which One Is The Best Rescue: Benadryl Or Zyrtec?

Zyrtec VS. Benadryl For Food Allergies

Benadryl and Zyrtec both are used to relieve symptoms of different types of allergies. According to the study about the effect of diphenhydramine and cetirizine in the treatment of acute food allergies, both proved to be equally effective.
 young woman choosing between zyrtec and benadryl for allergy

Zyrtec VS. Benadryl For Hives

Although both Zyrtec and diphenhydramine can be used for the treatment of hives, Zyrtec proves to be a better choice. Its effects last for a longer duration, and it does not cause drowsiness or sleepiness. Benadryl effects wear off after a few hours, and it also causes drowsiness and other undesirable effects.

Zyrtec VS. Benadryl For Itching

Both cetirizine and diphenhydramine could be used to relieve itching. Since diphenhydramine causes more side effects, cetirizine can be considered the better one for itching.
Based on the above discussion, cetirizine might be considered a better choice as compared to diphenhydramine. Benadryl is less safer, and it can also cause patients to become dependent on it. Diphenhydramine recreational use commonly happens because of ability of this drug to cause hallucinations. Although cetirizine dependency also exists, it has relatively lesser side effects, it is cheaper to use daily, and its once-a-day regimen makes it superior to diphenhydramine.

Page Sources

  1. https://pubs.niaaa.nih.gov/publications/arh23-1/40-54.pdf
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3205335/

Published on: June 5th, 2019

Updated on: July 16th, 2020

About Author

Sharon Levy, MD, MPH

After successful graduation from Boston University, MA, Sharon gained a Master’s degree in Public Health. Since then, Sharon devoted herself entirely to the medical niche. Sharon Levy is also a certified addiction recovery coach.


Leave a comment