Dr. M.J. Bazos MD, Patient Handout

Antihistamines

What are antihistamines?

Antihistamines are medicines that help stop the symptoms caused by allergies. Itchy eyes, sneezing and runny noses may be helped by an antihistamine. Sometimes, itchy rashes (especially hives) may also be helped by an antihistamine.

Why did my doctor give me a prescription when I can buy it "over-the-counter"?

Most antihistamines that you need a prescription for are the non-sedating type. That means they won't make you sleepy. If you've used an over-the-counter antihistamine, it probably made you sleepy. Non-sedating medicines are better for children during school hours and people who work with machinery or drive cars.

Can I take my prescription antihistamine with other medicines?

You shouldn't take prescription antihistamines and certain other prescription drugs--such as erythromycin, itraconazole (brand name: Sporanox) or ketoconazole (brand name: Nizoral)--at the same time. When your doctor gives you a prescription, always ask if it's safe to use with the other medicines you're taking. Your pharmacist can tell you the medicines you shouldn't take with a prescription antihistamine. If you aren't sure, ask the pharmacist or your doctor before taking another medicine.

Can I share my prescription antihistamines with friends who have allergies?

No. You should never share a prescription medicine with another person. Your doctor has examined you and has picked a medicine that is right for your problem. Some antihistamines can cause serious side effects if they are given to people who are taking another medicine, or who should not take antihistamines for another reason.