Dermatologists must be aware of the adverse effects of
antimicrobial agents as well as various drug interactions that may influence the choice of
drug as well as specific
drug schedules. The development of modern antibacterials has improved the treatment of cutaneous
bacterial infections.
Macrolide antibacterials continue to be an important therapeutic class of drugs with established efficacy in a variety of skin
infections. All
macrolides inhibit
protein synthesis by reversibly binding to the
23S ribosomal RNA in the 50S-subunit.
Erythromycin, the prototype of
macrolide antibacterials, was isolated from the metabolic products of a strain of Streptomyces erytherus in 1952. Originally,
erythromycin was introduced as an alternative to
penicillin because of its activity against the Gram-positive organisms. Numerous studies have demonstrated the efficacy and safety of
erythromycin for various
infectious diseases. Unfortunately,
erythromycin is associated with a number of drawbacks including a narrow spectrum of activity, unfavorable pharmacokinetic properties, poor gastrointestinal tolerability, and a significant number of
drug-drug interactions. Newer
macrolides have been developed to address these limitations. The pharmacokinetics of
azithromycin and
clarithromycin allow for shorter dosing schedules because of prolonged tissue levels. The efficacy of
azithromycin for the treatment of skin and
soft tissue infections in adults and children is well established. The unique pharmakinetics of
azithromycin makes it a suitable agent for the treatment of
acne.
Clarithromycin represents a clear advance in the
macrolide management of patients with
leprosy and skin
infections with atypical mycobacteria.
Dirithromycin and
roxithromycin display no clinical or bacteriological adcantage over
erythromycin despite a superior pharmacokinetic profile. An area of concern is the increasing
macrolide resistance that is being reported with some of the common pathogens which may limit the clinical usefulness of this class of
antimicrobial agents in future.