Lymecycline and minocycline in inflammatory acne: a randomized, double-blind intent-to-treat study on clinical and in vivo antibacterial efficacy.

BACKGROUND: Some antibiotics represent a mainstay in acne treatment. However, studies comparing their efficacies are rare. AIM: To evaluate the clinical and in vivo antibacterial effect of lymecycline and minocycline at different dosages. METHOD: Eighty-six patients with moderate to severe acne were enrolled in a randomized, double-blind, intent-to-treat study comparing in three parallel groups the effect of (1) lymecycline 300 mg daily for 12 weeks, (2) minocycline 50 mg daily for 12 weeks and (3) minocycline 100 mg daily for 4 weeks followed by 50 mg daily for 8 weeks. Evaluations were made at the screening visit and at five on-treatment visits. They consisted of clinical counts of acne lesions and evaluations of bacterial viability using dual flow cytometry performed on microorganisms collected from sebaceous infundibula by cyanoacrylate strippings. RESULTS: Patients receiving minocycline 100/50 mg had the best clinical outcome, particularly in the reduction of the number of papules. By the end of the trial, the microbial response to minocycline 100/ 50 mg was also superior to either of the other two treatments. There were less live and more dead bacteria. CONCLUSION: In this trial, minocycline 100/50 mg was superior for the treatment of inflammatory acne when compared to lymecycline 300 mg and minocycline 50 mg.