Do NOT use Erythromycin if:

• you are allergic to any ingredient in Erythromycin
• you are taking astemizole, cisapride, conivaptan, diltiazem, dofetilide, an ergot alkaloid (eg, dihydroergotamine, ergotamine), everolimus, an HIV protease inhibitor (eg, ritonavir), an imidazole (eg, ketoconazole), nilotinib, pimozide, a QT-prolonging agent (eg, quinidine, sotalol), a quinolone (eg, ciprofloxacin), a streptogramin (eg, quinupristin/dalfopristin), terfenadine, or verapamil.

Contact your doctor or health care provider right away if any of these apply to you.

Some medical conditions may interact with Erythromycin. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

• if you are pregnant, planning to become pregnant, or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you have diarrhea or a stomach or intestinal infection
• if you have a history of kidney or liver disease, heart problems, a fast or irregular heartbeat, myasthenia gravis, or the blood disease porphyria.

Some medicines may interact with Erythromycin. Tell your health care provider if you are taking any other medicines, especially any of the following:

• Astemizole, cisapride, diltiazem, dofetilide, an HIV protease inhibitor (eg, ritonavir), imidazoles (eg, ketoconazole), nilotinib, pimozide, a QT-prolonging agent (eg, quinidine, sotalol), a quinolone (eg, ciprofloxacin), a streptogramin (eg, quinupristin/dalfopristin), terfenadine, or verapamil because side effects, such as heart toxicity or irregular heartbeat, may occur. Check with your doctor if you have questions about which medicines may affect your heartbeat.
• Conivaptan, ergot alkaloids (eg, dihydroergotamine, ergotamine), or everolimus because the risk of their side effects may be increased by Erythromycin
• Many prescription and nonprescription medicines (eg, used for aches and pains, allergies, blood thinning, breathing problems, cancer, diabetes, erection problems, gout, heart problems, high blood calcium levels, high blood pressure, high cholesterol, HIV infection, inflammation, infections, low blood sodium levels, migraine, mood or mental problems, overactive bladder, Parkinson disease, prevention of organ transplant rejection, seizures, stomach problems, trouble sleeping), multivitamin products, and herbal or dietary supplements (eg, herbal teas, coenzyme Q10, garlic, ginseng, ginkgo, St. John's wort) may also interact with Erythromycin. Ask your doctor or pharmacist if you are unsure if any of your medicines might interfere with Erythromycin.

This may not be a complete list of all interactions that may occur. Ask your health care provider if Erythromycin may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

Important safety information:

• Mild diarrhea is common with antibiotic use. However, a more serious form of diarrhea (pseudomembranous colitis) may rarely occur. This may develop while you use the antibiotic or within several months after you stop using it. Contact your doctor right away if stomach pain or cramps, severe diarrhea, or bloody stools occur. Do not treat diarrhea without first checking with your doctor.
• Erythromycin only works against bacteria; it does not treat viral infections (eg, the common cold).
• Be sure to use Erythromycin for the full course of treatment. If you do not, the medicine may not clear up your infection completely. The bacteria could also become less sensitive to this or other medicines. This could make the infection harder to treat in the future.
• Long-term or repeated use of Erythromycin may cause a second infection. Tell your doctor if signs of a second infection occur. Your medicine may need to be changed to treat this.
• Tell your doctor or dentist that you take Erythromycin before you receive any medical or dental care, emergency care, or surgery.
• Rarely, patients taking Erythromycin have developed reversible hearing loss. The risk is greater if you have kidney problems or you take high doses of Erythromycin. Contact your doctor if you develop decreased hearing or hearing loss.
• Erythromycin may interfere with certain lab tests. Be sure your doctor and lab personnel know you are taking Erythromycin.
• Lab tests, including liver function, kidney function, and complete blood cell counts, may be performed while you use Erythromycin. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
• Pregnancy and breast-feeding: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Erythromycin while you are pregnant. Erythromycin is found in breast milk. If you are or will be breast-feeding while you use Erythromycin, check with your doctor. Discuss any possible risks to your baby.

All medicines may cause side effects, but many people have no, or minor, side effects.

Check with your doctor if any of these most common side effects persist or become bothersome:

Diarrhea; loss of appetite; nausea; stomach pain; vomiting.

Seek medical attention right away if any of these severe side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); bloody stools; decreased hearing or hearing loss; irregular heartbeat; muscle weakness; red, swollen, blistered, or peeling skin; seizures; severe diarrhea; severe stomach pain or cramps; symptoms of liver problems (eg, yellowing of the skin or eyes, pale stools, severe or persistent nausea, vomiting, loss of appetite, or dark urine).

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider.