Antibiotics Used to Treat Acne

Antibiotics are frequently used to treat acne since they help decrease the number of bacteria in and around the pilosebaceous unit, consisting of a hair follicle, sebaceous gland, and a hair. Acne is caused by the effects of hormones on this unit.

Specifically, the follicle becomes obstructed and an overgrowth of normal skin bacteria, Propionibacterium acnes, causes the destruction of the lining of the follicle. This process allows the follicular material to enter the dermis, causing an inflammatory response.

Antibiotics work by several mechanisms. The most important mechanism is the decrease in the number of bacteria in and around the follicle. Antibiotics also work by reducing the irritating chemicals produced by white blood cells. Finally, antibiotics reduce the concentration of free fatty acids in the sebum, also reducing the inflammatory response.

The most frequently used antibiotics for acne are summarized here.

Tetracycline is the most widely prescribed antibiotic for acne. The usual starting dose is 500 milligrams (mg) twice a day continued until a significant decrease in acne lesions is seen. The dose can then be decreased to 250 mg twice a day or discontinued.

Tetracycline should not be given to pregnant women or children under 9 years of age.

Erythromycin is a very commonly used antibiotic for acne. It has anti-inflammatory properties that help reduce redness in lesions in addition to killing bacteria.

The dosage of erythromycin varies with the type used, but it is typically prescribed as 250 - 500 mg twice a day.

Erythromycin is preferred over tetracycline for pregnant women and children under age 8.

Erythromycin is sold under the names: Ilotycin, Ery-Ped, Ery-tab, Staticin, Erythra-Derm, Akne-mycin, Pce, Eryc, Ery, Eryped, T-Stat, Erygel, and E.E.S.

Minocin (minocycline) is a tetracycline derivative that has been used effectively for decades as a treatment for acne. It is especially useful for pustular type acne. (A pustule is a pus-containing vesicle such as a whitehead surrounded by redness.)

While the absorption of minocycline is decreased with food, it is not as significant as the decrease seen with tetracycline. The usual starting dose is 50 to 100 mg twice a day.

Minocycline (and theoretically any tetracycline derivative) should be avoided in those who are using Accutane (isotretinoin) as the combination of these may result in a condition in which there is increased pressure within the skull (pseudotumor cerebri).

Doxycycline is often used for people who do not respond to or cannot tolerate erythromycin or tetracycline, or for those who will likely have difficulty with the "no food" guidelines of tetracycline (such as teenage boys.)

The dosage of doxycycline is started at 50 to 100 mg twice a day. It should be taken with food; otherwise, it can cause significant nausea.

There are other acne medications which may cause photosensitivity as well, such as benzoyl peroxide, alpha-hydroxy acids, and topical retinoids.

Doxycycline is available under these brand names: Doryx, Oracea, Monodox, Atridox, Morgidox, Vibra-Tabs, Alodox, Ocudox, Doxy, Acticlate, and Vibramycin.

Septra or Bactrim (sulfamethoxazole/trimethoprim) and Zithromax (azithromycin) a macrolide, have often been used to treat moderate to severe inflammatory acne.

Recent studies do not seem to favor one antibiotic over another with this condition, but treatment appears to work much better when combined with topical therapy.

Clindamycin is very useful as an oral antibiotic for acne, but it is most widely prescribed as a topical antibiotic. The starting dose is 75 to 150 mg twice a day.

The major side effect of clindamycin therapy is a serious intestinal infection called pseudomembranous colitis caused by the bacteria, Clostridium difficile. A Clostridium difficile infection is much more common with oral clindamycin but has been reported with the topical product as well.

Topical clindamycin is available as Cleocin-T, Clinda-Derm, Clindagel, Clindets, C/T/S, and Evoclin.

All antibiotics can cause vaginal yeast infections in women. Tetracycline seems to be the antibiotic that most frequently has this side effect.

All oral antibiotics can also lessen the effectiveness of birth control pills, so those who are taking these antibiotics should use a backup birth control method.

Nausea is fairly common with erythromycin and doxycycline.

In recent years we have been seeing increasing resistance of the bacteria Propionibacterium acnes against the oral antibiotics used.

Current strategies to reduce resistance (and hence, the lack of an effect of the antibiotics upon acne) recommend using antibiotics in combination with topical treatments and limiting the duration of use when possible.

Antibiotics can be very helpful for some people with acne and work by a combination of mechanisms.

Some antibiotics work better for particular types of acne and your dermatologist can make the best choice by understanding your history of acne as well as your lifestyle. As with any medications, side effects may occur. Fortunately, there are several different choices available if one of the above is not helpful.

Antibiotics are usually used in combination with topical treatments and good daily skin care for acne-prone skin.