Pharmacology Of Clindamycin

Indication For the treatment of serious infections caused by susceptible anaerobic bacteria, including Bacteroides spp., Peptostreptococcus, anaerobic streptococci, Clostridium spp., and microaerophilic streptococci. May be useful in polymicrobic infections such as intra-abdominal or pelvic infections, osteomyelitis, diabetic foot ulcers, aspiration pneumonia and dental infections. May also be used to treat MSSA and respiratory infections caused by S. pneumoniae and S. pyogenes in patients who are intolerant to other indicated antibiotics or who are infected with resistant organism. May be used vaginally to treat vaginosis caused by Gardnerella vaginosa. Clindamycin reduces the toxin producing effects of S. aureus and S. pyogenes and as such, may be particularly useful for treating necrotizing fasciitis. May be used topically to treat acne.
Pharmacodynamics Clindamycin is an antibiotic, similar to and a derivative of lincomycin. Clindamycin can be used in topical or systemic treatment. It is effective as an anti-anaerobic antibiotic and antiprotozoal.
Mechanism of action Systemic/vaginal clindamycin inhibits protein synthesis of bacteria by binding to the 50S ribosomal subunits of the bacteria. Specifically, it binds primarily to the 23s RNA subunit. Topical clindamycin reduces free fatty acid concentrations on the skin and suppresses the growth of Propionibacterium acnes (Corynebacterium acnes) , an anaerobe found in sebaceous glands and follicles.
Absorption Rapidly absorbed after oral administration with peak serum concentrations observed after about 45 minutes. Absorption of an oral dose is virtually complete (90%) and the concomitant intake of food does not appreciably modify the serum concentrations; serum levels have been uniform and predictable from person to person and dose to dose. Clindamycin does not penetrate the blood brain barrier.
Volume of distribution Not Available
Protein binding 92-94%
Metabolism Hepatic
Route of elimination Approximately 10% of the bioactivity is excreted in the urine and 3.6% in the feces; the remainder is excreted as bioinactive metabolites.
Half life 2.4 hours
Clearance Not Available
Toxicity Adverse effects include nausea (may be dose-limiting), diarrhea, pseudomembranous colitis, allergic reactions, hepatoxicity, transient neutropenia and eosinophilia and agranulocytosis. Pseudomembranous colitis occurs in 0.01 - 10% of patients and occurs more commonly than with other antibiotics. Use of the topical formulation of clindamycin results in absorption of the antibiotic from the skin surface. Diarrhea, bloody diarrhea, and colitis (including pseudomembranous colitis) have been reported with the use of topical and systemic clindamycin.