Penicillins Health Article

Side effects

The most common side effects are mild diarrhea, headache, vaginal itching and discharge, sore mouth or tongue, or white patches in the mouth or on the tongue. These problems usually go away as the body adjusts to the drug and do not require medical treatment unless they continue or they are bothersome.

More serious side effects are not common, but may occur. If any of the following side effects occur, get emergency medical help immediately:

• breathing problems, such as shortness of breath or fast or irregular breathing
• fever
• sudden lightheadedness or faintness
• joint pain
• skin rash, hives, itching, or red, scaly skin
• swelling or puffiness in the face

Other rare side effects may occur. Anyone who has unusual symptoms after taking penicillin should get in touch with his or her physician.

Interactions

Birth control pills may not work properly when taken at the same time as penicillin. To prevent pregnancy, use additional methods of birth control while taking penicillin, such as latex condoms or spermicide.

Penicillins may interact with many other medicines. When this happens, the effects of one or both of the drugs may change or the risk of side effects may be greater. Anyone who takes penicillin should let the physician know all other medicines he or she is taking. Among the drugs that may interact with penicillins are:

• Acetaminophen (Tylenol) and other medicines that relieve pain and inflammation
• medicine for overactive thyroid
• male hormones (androgens)
• female hormones (estrogens)
• other antibiotics
• blood thinners
• disulfiram (Antabuse), used to treat alcohol abuse
• antiseizure medicines such as Depakote and Depakene
• blood pressure drugs such as Capoten, Monopril, and Lotensin

The list above does not include every drug that may interact with penicillins. Be sure to check with a physician or pharmacist before combining penicillins with any other prescription or nonprescription (over-the-counter) medicine.

Nancy Ross-Flanigan

KEY TERMS

Enzyme—A type of protein that brings about or speeds up chemical reactions.

Microorganism—An organism that is too small to be seen with the naked eye.

Mononucleosis—An infectious disease with symptoms that include severe fatigue, fever, sore throat, and swollen lymph nodes in the neck and armpits. Also called "mono."