The white oval pill with the imprint 4H2 has been identified as Cetirizine Hydrochloride 10 mg supplied by Perrigo Company. Cetirizine is used to temporarily relieve the symptoms of hay fever (allergy to pollen, dust, or other substances in the air) and allergy to other substances (such as dust mites, animal dander, cockroaches, and molds). These symptoms include sneezing; runny nose; itchy, red, watery eyes; and itchy nose or throat. Cetirizine is also used to treat itching and redness caused by hives.
However, cetirizine does not prevent hives or other allergic skin reactions. Cetirizine is in a class of medications called antihistamines. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms. 4H2 pill is not a controlled substance under the Controlled Substances Act (CSA).
How should 4H2 pill be used?
Take 4H2 pill at around the same time every day. Follow the directions on your package label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take 4H2 pill exactly as directed. Do not take more or less of it or take it more often than directed on the package label or as recommended by your doctor.
Do not use 4H2 pill to treat hives that are bruised or blistered, that are an unusual color, or that do not itch. Call your doctor if you have these types of hives. Stop taking 4H2 pill and call your doctor if your hives do not improve during the first 3 days of your treatment or if your hives last longer than 6 weeks. If you do not know the cause of your hives, call your doctor.
If you are taking 4H2 pill to treat hives, and you develop any of the following symptoms, get emergency medical help right away: difficulty swallowing, speaking, or breathing; swelling in and around the mouth or swelling of the tongue; wheezing; drooling; dizziness; or loss of consciousness. These may be symptoms of a life-threatening allergic reaction called anaphylaxis. If your doctor suspects that you may experience anaphylaxis with your hives, he may prescribe an epinephrine injector (EpiPen). Do not use cetirizine in place of the epinephrine injector.
What side effects can 4H2 pill cause?
4H2 pill may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- drowsiness
- excessive tiredness
- dry mouth
- stomach pain
- diarrhea
- vomiting
Some side effects can be serious. The following symptom is uncommon, but if you experience it, call your doctor immediately:
- difficulty breathing or swallowing
Cetirizine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
What special precautions should I follow?
Before taking cetirizine,
- tell your doctor and pharmacist if you are allergic to cetirizine, hydroxyzine (Vistaril), or any other medications.
- tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: antidepressants, medications for anxiety, medications for mental illness, medications for seizures, other medications for cold and allergy, sedatives, sleeping pills, tranquilizers, and theophylline (Theo-24, Theolair). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor if you have or have ever had kidney or liver disease.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking cetirizine, call your doctor.
- you should know that cetirizine may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
- remember that alcohol can add to the drowsiness caused by this medication. Avoid drinking alcoholic beverages while taking this medication.
