Patients with severe acne benefit from most from oral drugs combined with topical medication, and doctors prescribe these drugs for some moderate cases of acne as well. Oral antibiotics are a standard acne therapy, according to the American Academy of Dermatology, and tetracycline antibiotics are often prescribed for this purpose. Periostat is brand name for a certain type of tetracycline antibiotic.
Antibiotics for Acne
Acne typically results from a combination of excessively oily skin, clogged pores and bacteria known as Propionibacterium acnes. Oral antibiotics decrease the P. acnes population, which then reduces inflammation. Tetracycline and two derivatives of this drug called doxycycline and minocycline are common acne treatments. The AAD notes that doxycycline is especially effective for treating inflammatory acne. Periostat is a brand name for a low-dose form of doxycycline.
Dosage
Doxycycline is used for treating other bacterial infections besides acne, such as urinary tract infections and Lyme disease. The recommended dose for most bacterial infections in adults is 100 mg to 200 mg per day, according to eMedTV. For acne, the usual dosage is 50 mg to 100 mg twice daily, according to Dr. Jan V. Hirschmann, writing in "Journal Watch Dermatology." Acne treatment sometimes begins with the higher dosage, which is then gradually reduced as the acne resolves. Periostat, at 20 mg per tablet or capsule, is a lower dose than other forms of doxycycline.
Effects
Low-dose doxycycline was originally developed for treating chronic periodontitis, or severe gum disease, in adults. Research has not shown that the 20 mg of doxycycline in Periostat decreases bacteria, according to DailyMed. Instead, it seems to work by reducing inflammation, explains an article by Dr. Seth T. Miller published in the "Journal of Family Practice" in August 2003. The low dosage taken twice a day does not appear to lead to bacterial resistance, a common problem with antibiotic therapy for acne.
Effectiveness
In the "Journal of Family Practice" article, the authors review a study led by R. Skidmore and published in "Archives of Dermatology" in April 2003. This study investigated whether low-dose doxycycline taken twice daily would be effective against moderate acne. Forty participants took either 20 mg doxycycline or a placebo twice daily for six months. The doxycycline group experienced a gradual reduction of inflammatory lesions, reaching about 50 percent fewer after six months, while the placebo group experienced about a 30 percent decrease. Comedones, or whiteheads and blackheads, were 53.6 fewer in the treatment group and 10.6 percent fewer in the placebo group. The "Journal of Family Practice" article notes that the placebo group had about twice as many men as the treatment group did, which could skew the results because male hormones have a significant role in acne.
Side Effects
Periostat side effects may include nausea, heartburn, diarrhea, joint pain and a rash. Tetracycline antibiotics, including Periostat, can cause photosensitivity, or heightened sensitivity to ultraviolet light, according to DailyMed. This can increase the risk of severe sunburn. As with any antibiotics, Periostat use can result in an overgrowth of existing fungi, such as Candida albicans, which may lead to a yeast infection. Pregnant women should not take doxycycline because it can cause fetal harm.
