Brand Name - Erythromycin Base

  • Type of Drug: Macrolide antibiotic.
  • Prescribed for: Infections of virtually any part of the body: upper and lower respiratory tract infections; some sexually transmitted diseases; urinary tract infections; infections of the mouth, gums, and teeth; and infections of the nose, ears, and sinuses. It is prescribed for acne and may be used for mild to moderate skin infections, but is not considered the antibiotic of choice, Erythromycin is effective against diphtheria as well as amoeba infections in the intestinal tract, which cause dysentery. It is also prescribed for Legionnaires’ disease, rheumatic fever, bacterial endocarditis, and a variety of other infections.

General Information

Erythromycin is a member of the group of antibiotics known as macrolides. This group of medicines, which also includes Azithromycin and Clarithromycin, are either bacteriocidal (they kill the bacteria directly) or bacteriostatic (they slow the bacteria’s growth so that the body’s natural protective mechanisms can kill them). Whether these drugs are bacteriostatic or bacteriocidal depends on the organism in question and the amount of antibiotic present in the blood or other body fluid. They are effective against all varieties of organisms, with each of the macrolide antibiotics working against a somewhat different profile of bacteria.

Erythromycin is absorbed from the gastrointestinal tract, but it is deactivated by the acid content of the stomach. Because of this, the tablet form of this drug is formulated to bypass the stomach and dissolve in the intestine.

Since the action of this antibiotic depends on its concentration within the invading bacteria, it is imperative that you follow the doctor’s directions regarding the spacing of the doses as well as the number of days you should continue taking Erythromycin. The effectiveness of this antibiotic can be severely reduced if these instructions are not followed.

Cautions and Warnings

Do not take Erythromycin if you are allergic to ft or to any of the macrolide antibiotics.
Erythromycin is excreted primarily through the liver. People with liver disease or damage should exercise caution and consult their doctors. Those on long-term therapy with Erythromycin are advised to have periodic blood tests.

Erythromycin is available in a variety of types and formulations. Erythromycin Estolate has occasionally produced liver difficulties, including fatigue, nausea, vomiting, abdominal cramps, and fever. If you are susceptible to stomach problems, Erythromycin may cause mild to moderate stomach upset. Discontinuing the drug will reverse this condition. If you restart Erythromycin after having experienced liver damage, it is likely that symptoms will recur within 48 hours.

A form of colitis (bowel inflammation) can be associated with all antibiotics, including Erythromycin. Diarrhea associated with the antibiotic may be an indication of this problem.

Possible Side Effects

  • Most common: nausea, vomiting, stomach cramps, and diarrhea. Colitis may develop after taking Erythromycin.
  • Less common: hairy tongue, itching, and irritation of the anal and/or vaginal region. If any of these symptoms appear, consult your physician immediately.
  • Rare: hearing loss (which reverses itself after the drug is “stopped and occurs most often in people with liver and kidney problems) and abnormal heart rhythms.

Erythromycin should not be given to people with known sensitivity to this antibiotic. It may cause yellowing of the skin and eyes. If this occurs, discontinue the drug and notify your doctor immediately.

Drug Interactions

• Erythromycin may slow the breakdown of Carbamazepine (for seizures) and Theophylline (for asthma), people taking these medicines should not use Erythromycin.
• Erythromycin may neutralize Penicillin and the antibiotics Lincomycin and Clindamycin; avoid these combinations.
• Erythromycin interferes; with the elimination of Theophylline from the body, which may cause toxic effects of Theophylline, overdose. It can also increase the effects of Caffeine, which is chemically related to Theophylline, on your body.
• Erythromycin may increase blood levels of Astemizole and Terfenadine, two nonsedating antihistamines broken down in the liver. This drug interaction may lead to serious cardiac toxicity and should be avoided.
• Erythromycin may increase blood levels of Alfentanil (an injectable pain reliever), Bromocriptine, Digoxin, Disopyramide, Ergotamine, Cyclosporine, Methylprednisolone (a corticosteroid), and Triazolam, resulting in an increase in drug effects as well as toxicities.
• Erythromycin Estolate may increase the toxic side effects of other drugs that can affect the liver.
• Erythromycin may increase the anticoagulant (blood-thinning) effects of Warfarin in people who take it regularly, especially older adults. People taking anticoagulant drugs who must also take Erythromycin may need their anticoagulant dose adjusted.

Food Interactions

Food in the stomach will decrease the absorption rate of Erythromycin Base and Erythromycin Stearate products. They are best taken on an empty stomach or 1 hour before or 2 hours after meals, but may be taken with food if they cause stomach upset. Other forms of Erythromycin can be taken without regard to food or meals. Check with your pharmacist for specific directions.

Usual Dose


  • Adult: 250 to 500 mg every 6 hours.
  • Child: 50 to 200 mg per pound of body weight per day in divided doses, depending upon age, weight, and severity of infection.

Eye Ointment

1/2-inch ribbon, 2 to 3 times per day.

Topical Solution

Apply morning and night.

Doses of Erythromycin Ethylsuccinate and Wyamycin are 60 percent higher due to differences in chemical composition.


Erythromycin overdose may result in exaggerated side effects, especially nausea, vomiting, stomach cramps, and diarrhea. Mild hearing loss, ringing or buzzing in the ears, or fainting may also occur. Call your local poison control center or hospital emergency room for more information.

Special Information

Erythromycin is a relatively safe antibiotic. It is used instead of Penicillin for mild to moderate infections in people who are allergic to the Penicillin class of antibiotics. Erythromycin is not the antibiotic of choice for severe infections.

Erythromycin products should be stored at room temperature, except for oral liquids and topical liquids, which should be kept in the refrigerator.

Take each dose of Erythromycin with 6 to 8 ounces of water. Call your doctor if you develop any of the following: nausea; vomiting; diarrhea; stomach cramps; severe abdominal pain; skin rash, itching or redness; dark or amber-colored urine; yellowing of the skin or eyes; or other severe or persistent side effects.

If you forget a dose of oral Erythromycin, take it as soon as you remember. If it is almost time for your next dose, space the next 2 doses over 4 to 6 hours, then go back to your regular schedule.

Remember to complete the full course of therapy prescribed by your doctor, even if you feel perfectly well after only a few days of antibiotic.

Special Populations

Erythromycin passes into the circulation of the developing fetus. Erythromycin Estolate has caused mild liver inflammation in about 10 percent of pregnant women and should not be used if you are, or may become, pregnant. Other forms of Erythromycin have been used safely without difficulty, Erythromycin passes into breast milk. Nursing mothers who are taking the drug should watch for side effects in their nursing infants, although this happens only rarely.

Older adults, except those with liver disease, may generally use this product without restriction.