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Bacterial resistance to antibiotics is an ongoing concern among clinicians. Inappropriate use of antibiotics has resulted in a dramatic drop in their effectiveness against several pathogensso much so that some companies have actually begun education programs to discourage the use of their products. As a result, antimicrobial agents with a history of less frequent usage are being reexamined and employed more often as alternative treatments. One such agent is clindamycin.
Clindamycin is a semisynthetic derivative of lincomycin with activity against many anaerobes as well as aerobic gram-positive cocci. Unlike penicillin, clindamycin retains its activity throughout the growth cycle of the bacteria.
Orally, clindamycin is used in the treatment of serious respiratory tract infections, skin infections, or septicemia from Staphylococcus aureus, Streptococcus pneumoniae, or other non-Enterococcal infections. Because of the concern over resistance or the development of superinfections by Clostridium difficile, clindamycin should not be used for minor skin or dental infections or for nonbacterial upper respiratory tract infections. Clindamycin is an alternative treatment for acute otitis media, pharyngitis, and tonsillitis in cases of penicillin or macrolide resistance or allergy.
Clindamycin also may be used in conjunction with oral quinine in the treatment of uncomplicated, chloroquine-resistant malaria. It is not effective, however, when used alone against Plasmodium falciparum
Clindamycin is an alternative oral agent in the prevention of bacterial endocarditis in penicillin-allergic patients with congenital heart disease, valvular heart dysfunction, surgically constructed pulmonary shunts, mitral valve prolapse, or previous episodes of bacterial endocarditis. Treatment with clindamycin also is recommended during dental or upper respiratory procedures that are likely to cause transient bacteremia with an increased risk of endocarditis.
One report discusses the postantibiotic effect of clindamycin persisting for a period of 4 to 6 hours after the antibiotic is removed.
Administration and Dosing
The dose of clindamycin can fluctuate with the severity of the infection but usually ranges from 150 to 450 mg every 6 hours. Pharyngitis and tonsillitis require a 10-day regimen. Adjunctive treatment for malaria requires treatment for at least a week.
For the prevention of bacterial endocarditis, the American Heart Association and the American Dental Association recommend that adults receive a single 600- mg dose of clindamycin 1 hour before upper respiratory or dental procedures.
To prevent esophageal irritation, oral clindamycin should be administered with a full glass of water. Food does not affect its absorption.
Safety Profile and Drug Interactions
The greatest concern about the use of clindamycin stems from its effectiveness. With the elimination of so much of the naturally occurring intestinal flora, superinfections by C difficile become possible. Clostridia in the colon create toxins that result in pseudomembranous enterocolitis, a potentially fatal condition. In addition, neutropenia from clindamycin therapy is rare but possible, related to direct toxicity from the antibiotic or from its metabolites.
With the emergence of penicillin-, sulfa-, and even quinolone-resistant strains of bacteria over the past decade, many clinicians will by necessity turn to alternative antibiotics to treat their patients. Although it carries restrictions of its own, clindamycin is gaining increased attention as other options become less effective.
Clindamycin is available in 150-and 300-mg capsules from Watson Pharmaceuticals Inc and Ranbaxy Pharmaceuticals Inc.
Mr. Middleton is an instructor of pharmacology for Kellogg Community College in Battle Creek, Mich.