- Zyrtec provides long-lasting relief with less drowsiness and is suitable for consistent use.
- Benadryl offers a faster onset of action for allergic reactions, motion sickness, and insomnia but can cause sedation.
- While both Zyrtec and Benadryl are effective OTC antihistamines, some individuals may find them insufficient or unsuitable due to side effects such as drowsiness.
When allergic rhinitis strikes, many people reach for an antihistamine to find relief from the discomfort of sneezing, congestion, and itchy eyes. Among the most common options are Zyrtec and Benadryl — two over-the-counter antihistamines.
If you're wondering which one is the right choice for you, you're not alone. In this article, we'll provide clarity on their key differences. We'll learn about each medication, including their indications, onset of action, duration of effect, and potential side effects.
Additionally, we'll suggest an alternative that is more tailored to your specific needs for managing your allergy symptoms.
Related: What to Do When Allergy Medicine Doesn't Work?
What is Zyrtec?
Zyrtec is an over-the-counter second-generation oral antihistamine commonly used to relieve allergy symptoms such as sneezing, runny nose, itchy or watery eyes, and nasal congestion.
Its active ingredient, cetirizine (a second-generation antihistamine), works by blocking the effects of histamine, which is a substance produced by the body during allergic reactions. Cetirizine works by binding to histamine receptors in the body to prevent histamine from exerting its effects [*].
Zyrtec is known for providing fast relief, as it usually begins to work within 20 minutes to 1 hour, and it is less likely to cause drowsiness compared to some other antihistamines. Zyrtec is available in various forms, including tablets, chewables, and syrup (for kids).
Related: Zyrtec vs. Claritin: Differences and Alternatives
What is Benadryl?
Benadryl is an over-the-counter antihistamine commonly used to treat symptoms of allergies, such as sneezing, runny nose, itchy eyes, itchy throat, and skin rashes.
Diphenhydramine, its active ingredient, is a first-generation antihistamine. These medications work by blocking H1 histamine receptors in the body, which prevents histamine from binding to these receptors. Diphenhydramine can cross the blood-brain barrier, meaning it affects the central nervous system (CNS). This is why it often causes sedation and drowsiness as a side effect [*].
In addition to allergy relief, Benadryl is also used to treat motion sickness, insomnia, and symptoms of the common cold. Benadryl is available in various forms, including tablets, liquid gels, chewables (for kids), and creams.
Related: Benadryl vs. Claritin: Differences and Alternatives
Zyrtec vs. Benadryl
To help you compare these two antihistamines at a glance, we’ve prepared a table summarizing their key differences, including their generic names, indications, side effects, duration of action, and more.
| Zyrtec | Benadryl | |
| Drug Class | Antihistamine (second-generation) | Antihistamine (First-generation) |
| Generic Name | Cetirizine | Diphenhydramine |
| Indications | Temporarily relieves common allergy symptoms caused by hay fever, seasonal allergies, or other respiratory allergies. These symptoms include a runny nose, sneezing, itchy or watery eyes, and itching in the nose or throat. | Relieve symptoms of allergies, such as sneezing, runny nose, itchy or watery eyes, and itching in the throat or nose. It is also used to treat hay fever, allergic reactions to insect stings or bites, and rashes caused by allergies. Benadryl can help with motion sickness, nausea, and insomnia. |
| Side Effects | Common side effects of Zyrtec include headache, dizziness, nausea, and dry mouth. Less drowsy than first-gen antihistamines but may still cause headache, dry mouth, dizziness, or fatigue. | Drowsiness, dizziness, dry mouth, blurred vision, constipation, or upset stomach. |
| Duration/Course | Relieves symptoms for a full 24 hours | 4 to 6 hours |
| Onset | Starts working at 1 hour | 15 to 30 minutes |
| Drug Interaction | May interact with CNS depressants (e.g., alcohol, sedatives) or certain seizure and antidepressant medications. | Potentiates sedative effects with alcohol or other CNS depressants. Can interact with medications like MAOIs. |
| Warnings/Precautions | Avoid if allergic to cetirizine or related compounds. Consult a doctor if pregnant, breastfeeding, or if you have liver/kidney issues. | Use cautiously in people with asthma, glaucoma, or enlarged prostate. Consult a doctor during pregnancy or breastfeeding. |
What’s the Best Alternative for Zyrtec and Benadryl for Nasal Allergies?
Unlike traditional antihistamines, which provide a one-size-fits-all approach, Allermi offers a customized treatment designed to address the root cause of nasal allergies.
Some individuals may find Zyrtec or Benadryl insufficient or unsuitable due to side effects like drowsiness or limited efficacy for their specific symptoms.
Allermi addresses these concerns by delivering a personalized nasal spray that combines multiple active ingredients (including an antihistamine, decongestant, anticholinergic, and anti-inflammatory) to target various aspects of nasal allergies.
Because of Allermi’s custom approach, many users report noticeable symptom improvement within 10-15 minutes of use. Over 3-4 weeks, the spray can deliver significant and lasting relief.
Whether you’re dissatisfied with the side effects of Zyrtec or Benadryl or need a solution that does more, Allermi’s customizable nasal spray is worth considering.
Related: How Long Does It Take for Allergy Medicine to Work?
The Bottom Line
Choosing the right treatment is an important step in managing your allergy symptoms. While Zyrtec and Benadryl are popular over-the-counter options with proven benefits, they cater to different needs and situations.
Zyrtec is ideal for those seeking 24-hour relief with minimal drowsiness, while Benadryl may be better suited for short-term use or additional conditions like motion sickness and insomnia.
If you find these options lacking for your nasal allergies, choose Allermi as an alternative. Learn the science behind Allermi here.
References:
- Zhang, L., Cheng, L., & Hong, J. (2013). The Clinical Use of Cetirizine in the Treatment of Allergic Rhinitis. Pharmacology, 92(1–2), 14–25. https://doi.org/10.1159/000351843
- Simon, F. E. R., & Simons, K. J. (2008). H1 Antihistamines: Current Status and Future Directions. World Allergy Organization Journal, 1(9), 145–155. https://doi.org/10.1186/1939-4551-1-9-145
