Detailed Drug Information:

DRUG CLASS AND MECHANISM: Most infections are caused by bacteria that invade and grow in the human body. Medications that control or eradicate these bacteria are called antibiotics. Erythromycin is an antibiotic that prevents bacteria from producing proteins, which interferes with bacterial growth and multiplication, while not affecting human cells.

PREPARATIONS: Tablets: usually 250mg and 500mg. Liquid,capsules, and topical solutions also available.

STORAGE: Erythromycin should be stored at temperatures below 86 degrees F.

PRESCRIBED FOR: Erythromycin can be used to treat Streptococcal infections of the throat (strep throat) and the skin. It can also be used in treating lung infections (pneumonias) caused by streptococcal pneumoniae, mycoplasma pneumoniae, and legionella pneumophila (Legionnaires disease). Erythromycin is used in patients who are allergic to penicillin for the prevention of recurrent rheumatic fever, and heart valve infections (endocarditis) in patients with heart valve abnormalities before undergoing dental treatments. For further information, please read the Mitral Valve Prolapse, and Aortic Stenosis articles. Erythromycin is also used for the treatment of staphylococcal infections of the skin, and as an alternative drug for syphilis, gonorrhea, and Chlamydia.

DOSING: Erythromycin may be taken with or without food. Erythromycin is metabolized mainly by the liver and caution should be used in patients with abnormal liver function.

DRUG INTERACTIONS: Erythromycin administered together with theophylline can lead to elevated blood levels of theophylline. Theophylline is used to open airways in the treatment of asthma. Forfurther reading, please read the Asthma article. Toxic levels of theophylline can lead to seizures and disturbances in heart rhythm. Therefore, the dose of theophylline should be reduced in patients also taking erythromycin. Likewise, erythromycin can raise the blood levels of digoxin and warfarin (Coumadin). Elevated digoxin levels can cause disturbances in heart rhythm. Enhanced action of Coumadin (an anticoagulant) can increase risk of bleeding. Serious heart rhythm disturbances (even cardiac arrest) have been observed when erythromycin and terfenadine (Seldane) are used together. Erythromycin can interact with lovastatin (Mevacor) to cause muscle inflammation. Erythromycin can also elevate blood levels of certain anti-seizure medications such as phenytoin (Dilantin), and carbamazepine (Tegretol). The doses of these medications may need to be reduced when given together with erythromycin.

SIDE EFFECTS: The most frequent side effects of erythromycin are nausea, vomiting, loss of appetite, diarrhea, and abdominal pain. These gastrointestinal side effects are usually dose related (side effects are more pronounced with higher doses of the medication). Allergic reactions such as hives, rash, or anaphylaxis (a severe allergic reaction which can lead to shock) have been rarely reported. Abnormal liver tests or liver dysfunction can also occur with erythromycin.