Benzamycin is a combination of erythromycin and benzoyl peroxide and is used for the topical treatment of acne (pimples). Erythromycin is an antibiotic. The exact mechanism by which topical erythromycin reduces pimples is unknown. Erythromycin probably reduces pimples by penetrating into the skin and killing bacteria that contribute to the formation of pimples. Benzoyl peroxide works through several mechanisms. It kills the bacteria and promotes the growth of new skin cells. It also dries the skin. Increased cell growth leads to replacement of the pimples with new skin. Combining erythromycin and benzoyl peroxide is more convenient than using them separately. The FDA approved Benzamycin in November 2000.

Benzamycin

GENERIC AVAILABLE: Yes

Yes

The most common side effects are:

• skin irritation,
• redness,
• peeling,
• dryness, and
• itching.

Most of these side effects lessen with continued use. If they are bothersome, decreasing the frequency of application could be helpful. Skin discoloration and tenderness also may occur. Benzamycin may increase sensitivity to the sun leading to sunburn. Excessive sun exposure should be avoided, and sunscreen should be used over treated areas if sun exposure cannot be avoided. Benzamycin should not be applied to sunburned skin, cuts, eyes, nose or lips. Benzamycin may bleach hair or colored fabric.

The affected areas are washed and dried, and a thin layer of gel is applied twice daily (morning and evening) or as directed by a physician. The eyes, lips and nose should be avoided. Results should be seen within 4 to 6 weeks. This product is for external use only.

Excessive skin irritation may occur if Benzamycin is used with other acne medications.

Safety of Benzamycin when used during pregnancy has not been established; however, the risk of side effects on the fetus is low because very little drug is absorbed through the skin.

The possibility that infants will experience adverse effects due to the use of Benzamycin by a woman who is breastfeeding is very low since little drug is absorbed through the skin.

What preparations of erythromycin and benzoyl peroxide are available?

Benzamycin is dispensed in amounts of 46.6 gm containing 1.6 grams of erythromycin powder and 40 grams of benzoyl peroxide gel. The erythromycin powder is mixed with 6 ml of ethyl alcohol and then added to the benzoyl peroxide gel before it is dispensed to the patient. Benzamycin also is available as Benzamycin Pak, 60 individual-use packets containing both erythromycin and benzoyl peroxide as gels in separate compartment within the packet. Just prior to use, the packet is opened, and the gels are mixed.

How should I keep erythromycin and benzoyl peroxide stored?

Prior to mixing the erythromycin and benzoyl peroxide together, Benzamycin should be stored at room temperature, 15 C - 30 C (59 F - 86 F). After mixing, Benzamycin should be stored in the refrigerator between 2 C - 8 C (36 F – 46 F) and discarded after 3 months.