Efficacy of tetracyclines in the treatment of acne vulgaris: a review

Background Oral tetracyclines are routinely used for the management of inflammatory acne. However, there is a lack of evidence-based data on their relative effectiveness and appropriate dosages. Objectives To assess the relative effectiveness and the optimal dosage of tetracyclines for the treatment of inflammatory acne. Methods We designed a systematic review of the clinical trials (1962-2006) investigating oral tetracyclines for the treatment of inflammatory acne. We obtained data from MEDLINE, PubMed, Current Contents, reference lists and specialist textbooks. Results There was substantial heterogeneity in the design of the trials. We identified only seven randomized trials which were set up to compare the efficacy of tetracyclines in reducing acne lesion counts. These showed no evidence of superiority of one tetracycline over another. Overall, there was also no significant difference between the available tetracyclines in terms of improvement in inflammatory (32 trials, P = 0.898) and noninflammatory (23 trials, P = 0.429) lesions. In the range of investigated dosages, the antibiotic dosage had no impact on efficacy in inflammatory (P = 0.609) and noninflammatory (P = 0.654) lesions. There was no decrease in efficacy during the study period. Conclusions There is insufficient evidence to support one tetracycline rather than another in terms of efficacy. In the range of investigated dosages, the antibiotic dosage seems to have no impact on efficacy. Despite increased resistance to antibiotics, oral tetracycline formulations displayed no change in efficacy during the study period. Further studies are, however, required to determine if the anti-inflammatory properties of tetracyclines are sufficient in managing acne.