DOXYCYCLINE IS EFFECTIVE (strength of recommendation [SOR]: B, randomized controlled trial) and the antibiotic of choice (SOR: C, expert opinion) for moderate to severe inflammatory acne requiring oral treatment. Limiting side effects include photosensitivity and gastrointestinal (GI) disturbance.
Other members of the tetracycline family are considered second-line agents because of their side-effect profile and are contraindicated in pregnancy and for children younger than 12 years (SOR: A, meta-analysis, and C, expert opinion). For these patients, erythromycin is effective and better studied than azithromycin (SOR: C, expert opinion). Otherwise, emerging resistance and GI disturbances make erythromycin a third-line treatment.
The use of oral antibiotics should be limited to moderate to severe inflammatory acne unresponsive to topical therapies, including retinoids and antibiotics (SOR: C, expert opinion). Oral antibiotics should be used for at least 6 to 8 weeks and discontinued after 12 to 18 weeks of therapy (SOR: C, expert opinion).
Acne vulgaris is an extremely common disorder affecting up to 95% of adolescents.1 Doxycycline improves inflammatory lesions and has a tolerable side-effect profile.
Doxycycline: Fewer lesions, few side effects
A 2003 randomized, double-blind, controlled trial of 51 patients demonstrated that a subantimicrobial dose of doxycycline (20 mg orally twice a day) reduced comedonal lesions by 53.2% (from 31 to 16; P=.04) and inflammatory lesions by 50.1% (from 55 to 25; P<.01), whereas placebo decreased comedonal lesions by 10.6% (from 51 to 46; P=.4) and inflammatory lesions by 30.2% (from 27 to 19; P<.01).2
The most commonly reported adverse effects of doxycycline are GI disturbance and sensitivity to ultraviolet radiation (sunlight). A recent systematic review found an adverse event rate of 13 per 1 million prescriptions written.3
Minocycline: Probably effective, but not the first choice
A 2003 Cochrane review examined 27 randomized trials that compared oral minocycline with placebo or other active treatments, including topical and systemic antibiotics, in a total of 3031 patients with acne vulgaris on the face or upper trunk.4 The review determined that minocycline is probably an effective treatment for moderate acne vulgaris. However, no reliable evidence from randomized controlled trials (RCTs) justifies its use as a first-line agent, especially given its higher cost relative to other treatments.
Drug resistance weakens macrolides’ “punch”
Macrolide antibiotics, primarily erythromycin, were at one time considered first-line treatment for acne, but have fallen out of favor because of emerging drug resistance. Nevertheless, erythromycin’s price and safety in pregnant women and young children has maintained its standing in acne therapy. A 1986 RCT that compared erythromycin with tetracycline found comparable efficacy: a 65% reduction in papules, from 21 to 12 lesions, for erythromycin and a 62% reduction, from 17 to 10 lesions, for tetracycline (P<.0001).5 The main side effect of macrolide antibiotics is GI disturbance.