Written & medically reviewed by Dr. Andrew C. Engler, MD
Medical Director, The Allergy Clinic
Published: · Medically reviewed:
The table below compares common over-the-counter allergy medication classes. Individual response varies — read each product’s Drug Facts label and ask a clinician if you have other medical conditions or take other medicines.
| Medication class | Brand examples | Onset of action | Duration | Sedating? | Best for |
|---|---|---|---|---|---|
| Second-generation oral antihistamine | Zyrtec (cetirizine), Claritin (loratadine), Allegra (fexofenadine), Xyzal (levocetirizine) | About 1 hour | Up to 24 hours | Generally no; cetirizine may cause drowsiness in some people | Daytime sneezing, itchy or watery eyes, and runny nose |
| First-generation oral antihistamine | Benadryl (diphenhydramine) | About 15–30 minutes | About 4–6 hours | Yes | Short-term relief; often used at night because of drowsiness. Not intended for everyday long-term use |
| Nasal steroid spray | Flonase (fluticasone), Nasacort (triamcinolone), Rhinocort (budesonide) | Several hours; fullest effect after several days of daily use | About 24 hours with daily use | No | Nasal congestion, inflammation, and seasonal or year-round allergic rhinitis |
| Nasal antihistamine spray | Astepro (azelastine) | About 15–30 minutes | About 12–24 hours | Can cause drowsiness in some people | Itchy or runny nose and sneezing when faster nasal relief is needed |
| Oral or nasal decongestant | Sudafed (pseudoephedrine); Afrin (oxymetazoline) | Minutes to about 30 minutes | Oral: about 4–12 hours depending on the formula; nasal spray: up to 12 hours | No; can cause jitteriness or raise blood pressure | Stuffy nose only. Do not use decongestant nasal sprays longer than 3 days — longer use can cause rebound congestion |
| Mast cell stabilizer | NasalCrom (cromolyn sodium) | Delayed; works best with regular use | About 4–6 hours (used several times a day) | No | Prevention of nasal allergy symptoms, especially if started before allergen exposure |
Decongestant nasal sprays such as oxymetazoline (Afrin) should not be used for more than 3 days. Longer use can lead to rebound congestion, in which stuffiness returns or worsens when the spray is stopped.
Antihistamines are a cornerstone of allergy treatment. They block the effects of histamine, a chemical your body releases during an allergic reaction. By doing so, antihistamines help relieve sneezing, a runny nose, watery eyes, and an itchy throat. Popular OTC antihistamines include cetirizine (Zyrtec), fexofenadine (Allegra), and loratadine (Claritin). These “second-generation” antihistamines are less likely to cause drowsiness than older medications like diphenhydramine (Benadryl). The choice between these often depends on how quickly you need symptom relief, how long you want it to last, and your tolerance to possible side effects. Most oral antihistamines are taken once daily. Always follow package instructions, as some products may differ in dosing, especially for children or older adults.
For more on antihistamine options, see Allergy Antihistamines & Medication.
Decongestants temporarily relieve nasal stuffiness by shrinking swollen blood vessels in your nasal passages. Common oral decongestants include pseudoephedrine and phenylephrine. Nasal decongestant sprays (like oxymetazoline) deliver fast relief directly to the nasal tissues. However, using them for more than three consecutive days can lead to rebound congestion, making nasal allergy symptoms worse. Always use these sprays according to the package directions.
Learn more about nasal spray options and their benefits at our allergic rhinitis page.
Yes. Cetirizine (Zyrtec) and fluticasone nasal spray (Flonase) work in different ways — one blocks histamine, the other reduces nasal inflammation. Many people use both when a single product does not control symptoms. Read each product’s Drug Facts label, and ask a clinician if you have other medical conditions or take other medicines.
Diphenhydramine (Benadryl) is intended for short-term relief, not everyday long-term use. It commonly causes drowsiness and can impair driving or work, so first-generation antihistamines are generally not preferred for daily allergy control. A non-drowsy second-generation antihistamine or a nasal steroid spray is usually a better option for ongoing symptoms — check with a clinician before using Benadryl regularly.
All three are second-generation oral antihistamines used for sneezing, itchy or watery eyes, and runny nose. Cetirizine (Zyrtec) often starts working in about an hour and may cause drowsiness in some people; loratadine (Claritin) and fexofenadine (Allegra) are typically less sedating. Which one works best varies by person — if one does not help after several days of correct use, another in this class may.
Do not use oxymetazoline (Afrin) or similar decongestant nasal sprays for more than 3 days. Longer use can cause rebound congestion, in which stuffiness returns or worsens when the spray is stopped. For longer-lasting nasal relief, a corticosteroid nasal spray used daily is typically a better choice.
See an allergist if symptoms persist despite correct use of OTC medicine, if they interfere with sleep or daily life, if you need medicine most days of the year, or if you have asthma, recurrent sinus infections, or reactions that suggest more than simple hay fever. An allergist can identify triggers and discuss options such as prescription therapy or allergen immunotherapy.
For more information or to book a consultation, visit the Allergy & Asthma Clinic or explore telehealth options.
While OTC allergy medicines can provide significant relief, not all symptoms respond equally to non-prescription options. At our clinic, you’ll find specialized information, support, and a commitment to helping you breathe easier year-round. Whether you’re struggling with seasonal allergies, indoor triggers like dust or pets, or food sensitivities, the Allergy & Asthma Clinic offers up-to-date resources and expert insights to help you take control of your health with allergy immunotherapy, nasal corticosteroids, and other treatments.
Choosing the over-the-counter allergy medicine comes down to matching the right product to your specific symptoms and medical needs. With various effective options available, relief is within reach for most allergy sufferers. For persistent or severe allergic rhinitis or guidance tailored to your unique situation, trusted resources like the Allergy & Asthma Clinic are always ready to help with allergy shots and other advanced treatments.
About the Author
Dr. Engler received his Bachelor of Art degree, with distinction, from Stanford University in 1978. He was elected to the Phi Beta Kappa society when he was still a junior in college. After two years as a medical student at Yale, he returned to Stanford, where he received his M.D. degree in 1982. He went on to complete his internship and residency at Stanford University Hospital and is Board Certified in Internal Medicine. Dr. Engler then received several years of additional training in Allergy, Asthma, and Immunology. He founded The Allergy Clinic in San Mateo in 1987.
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First and foremost let me start by saying that these people did one hell of a job figuring out my sinus problems. When I first arrived there, I explained what was going on with me having excessive inflammation in the sinus…after they tested me, I found out that I was being exposed to dust mites which gave me a strong reaction. I followed the doctors guides lines in terms of cleaning my room and ever since, my sinus inflammation went away for good and now I have a healthy sinus. Thank you for everything.
My 10 year old son also has allergies and asthma and the staff makes sure that he feels well taken care of and comfortable, despite his having Autism and ADHD. He actually looks forward to going there with me, whether it be for my allergy shots or even when he needed allergy skin testing. When you’re a patient at the Allergy and Asthma clinic, you are treated as if you are the only patient they have, even when the waiting room is full. Dr. Engler has hired truly excellent staff, from the front desk people to the nurses and medical assistants. If you have allergies and/or asthma and you live on the Peninsula or even in the city, I highly recommend that you visit the Allergy and Asthma Clinic. They are truly amazing and will make you feel so much better.
