Difference Between Zyrtec and Benadryl


Main Difference

The main difference between Zofran and Phenergan is that Zofran has Ondansetron HCL as an active pharmaceutical ingredient while Phenergan has Promethazine as an active pharmaceutical ingredient.

Zyrtec vs. Benadryl

Zyrtec contains cetirizine hydrochloride, on the other hand, Benadryl contains diphenhydramine hydrochloride. Zyrtec belongs to 2nd generation antihistamines whereas Benadryl is ist generation antihistamines. Zyrtec causes less sleepiness, on the other hand, Benadryl causes more sleepiness. Zyrtec shows its pharmacological actions for 12-24 hrs while Benadryl shows its pharmacological actions for 12hrs. Zyrtec is not prescribed for the treatment of hives, on the other hand, Benadryl is the best option for the treatment of hives. Zyrtec tablet, quick-dissolving tablet, and liquid are available on the other hand, Benadryl talent, quick-dissolving tablet, liquid, and capsules are available. Zyrtec is given 5-10mg as single adult dose, on the other hand, Benadryl is given 25-50mg as single adult dose. Zyrtec causes less tiredness, on the other hand, Benadryl causes more tiredness.


Comparison Chart

Zyrtec is the brand name of cetirizine hydrochloride and is used to treat allergies.Benadryl is the brand-name of diphenhydramine and is used to address seasonal and other allergies.
Drug Group
2nd generation AntihistamineIst generation Antihistamine
Active Therapeutic Agent
Cetirizine HCLDiphenhydramine hydrochloride
Duration of Action
12-24 hrs12 hrs
Dosage Forms
Tablet, Quick dissolving tablet, and LiquidTablet, Quick dissolving tablet, Liquid, and Capsule.
Therapeutic Uses
Allergic rhinitis, Urticarial, DermatitisAllergies, Seasonal allergies including sneezing, itchy throat and itchy watery eyes
Sleep induction

What is Zyrtec?

Zyrtec is the brand name of cetirizine hydrochloride which is 2nd generation antihistamine and belongs to the chemical class of piperazine. Zyrtec is used in many immediate hypersensitivity reactions like allergic rhinitis, urticarial, and dermatitis. Zyrtec shows its therapeutic actions by blocking the HI receptors. Zyrtec starts to show its pharmacological actions in an hour. The effects of the pharmacological actions of the Zyrtec remains for a day. The therapeutic benefits of Zyrtec are same as that of diphenhydramine. Zyrtec causes sleepiness as a side effect, but the degree of it is less than that of the ist generation antihistamines. Other side effects of the Zyrtec include abdominal pain, headache, and dry mouth. Serious side effects of the Zyrtec are angioedema and aggression. Pregnant women can use Zyrtec, but its use in breastfeeding mothers is not recommended. Zyrtec is used in allergies because in allergies, the redness is caused by the histamine action on H1 receptors, and as Zyrtec blocks these receptors, so it does not allow histamine to further cause its effects. Among all other 2nd generation antihistamines the Zyrtec is the best choice to treat acute or chronic urticarial. Zyrtec is available as 5, 10, and 20mg tablets. When Zyrtec use is stopped after prolonged use, then patients suffer from itching. Zyrtec is well absorbed after oral administration both in tablet and syrup form. Zyrtec does not interact with many drugs because it is not metabolized by the cytochrome P450 enzyme system. Zyrtec is metabolized by chemical reactions like oxidation and conjugation. Zyrtec is eliminated from body majorly by urine and to a minor extent by the feces.


What is Benadryl?

Benadryl is the brand-name of diphenhydramine that is classified as an antihistamine. Benadryl salt is diphenhydramine hydrochloride. Benadryl is the over-the-counter medication. Benadryl is used to treat symptoms of seasonal allergies like sneezing, itchy throat, and itchy watery eyes or other allergies; it also relieves symptoms of the common old and itchy skin due to hives or insect bites. Benadryl is considered the first-choice treatment for the treatment of hives. Benadryl is used orally or topically. Benadryl is marketed without a prescription. Benadryl causes some sleepiness, and it is not recommended in children under the age of six. Benadryl gel products contain a high level of drug, and if swallowed mistakenly, the Benadryl gel products can cause the loss of consciousness or/and confusion. Benadryl tablets contain inactive ingredients like colloidal silicone dioxide, crospovidone, candelilla wax, hypromellose, polyethylene glycol, providone, talc pregelatinized starch, microcrystalline cellulose starch, , titanium dioxide, and stearic acid. Benadryl is prescribed in the dose of 25-50mg to adults and children of age 12 and above. Benadryl is prescribed in the dose of 12.5mg to 25mg in patients of age 6-12. Benadryl is prescribed in the children under the age of six after consulting a physician.12.5 mg strength is not available in the capsule form. Benadryl is sensitive to light so that it should be packed in containers which are protected from light. Benadryl is stored at a temperature of 59-77 F in a dry place. Different forms of Benadryl which are available are oral tablets, oral chewable tablets, oral liquid fill capsules, oral liquid solution, topical cream, topical gel, topical spray, and topical stick.

Key Differences

  1. Zyrtec is brand of Cetrizine hydrochloride on the other hand Benadryl is brand of the diphenhydramine hydrochloride
  2. Zyrtec is a 2nd generation antihistamine, on the other hand, Benadryl is ist generation antihistamine.
  3. Zyrtec has low tendency to induce sleep while Benadryl has a high tendency to induce sleep.
  4. Zyrtec is not a better option to treat hives; on the other hand, Benadryl is a better option to treat hives.
  5. Zyrtec has a duration of action of 12 -24 hrs while Benadryl has a duration of action of 12 hrs.
  6. Zyrtec is available as the tablet, quick-dissolving tablet, and liquid, on the other hand, Benadryl is available as a tablet, quick-dissolving tablet, liquid, and capsule.
  7. Zyrtec single dose of adults is 5-10mg while Benadryl single dose of adults is 25-50mg.
  8. Zyrtec causes less tiredness as compared to Benadryl; on the other hand, Benadryl causes more tiredness as compared to Zyrtec.


The main conclusion of the above discussion is that both Zyrtec and Benadryl are antihistamines and are effectively used to treat allergies.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White