Based on mean inhibitory concentration testing with C. acnes, some evidence has shown MCN to have the lowest resistance susceptibility and lowest cross resistance,44-47 as well as the largest log reductions in C. acnes, when compared to doxycycline and multiple other antibiotics.40,48 Although oral MCN has a low propensity for antibiotic resistance,49 which has contributed to its longevity, resistance following antibiotic use is always a concern. Therefore, good antibiotic stewardship and judicious use is important to preserve an antibiotic’s utility.19
Because of its lipophilicity, MCN more easily crosses the blood brain barrier, and vestibular adverse events (AEs) are the most common side effects seen with MCN. These types of AEs are minimized when weight-based dosing and an extended release formulation (MCN ER) are employed.50 There is negligible phototoxicity seen with MCN.22 Hyperpigmentation can occur in patients taking higher doses of MCN for longer periods of time, but has rarely been seen with extended-release formulations, presumably because cumulative doses are so low. Serious idiosyncratic hypersensitivity or autoimmune reaction AEs have been reported but are rare, on the order of 1 in a million. Overall, MCN generally has a good safety record.51
