Clindamycin

Clindamycin is an antibiotic used to treat a number of bacterial infections, including bone or joint infections, pelvic inflammatory disease, strep throat, pneumonia, otitis media, and endocarditis. It can also be used to treat acne, and some cases of methicillin-resistant Staphylococcus aureus (MRSA). In combination with quinine, it can be used for malaria. It is available by mouth, by injection into a vein, and as a cream to apply to the skin or vagina.

Pharmacodynamics

Clindamycin has a primarily bacteriostatic effect. However, in higher concentrations it may also be bactericidal. It is a bacterial protein synthesis inhibitor by inhibiting ribosomal translocation, similar to the group of macrolide antibiotics. It does this by binding to the 50S rRNA of the large bacterial ribosomal subunit. The binding is reversible.

Pharmacokinetics

Oral bioavailability is very high at approximately 90%, and maximum serum concentrations (Cmax) are reached after approximately 0.75 hours (Tmax). Protein binding of clindamycin is concentration dependent and ranges from 60-94 %. Clindamycin undergoes hepatic metabolism mediated mainly by CYP3A4 and to a lesser extent by CYP3A5. Clindamycin and its metabolites are largely excreted by the kidneys. The half-life is 12-17 hours.

Drug Interactions

Clindamycin may prolong the effects of neuromuscular blocking drugs, such as succinylcholine and vecuronium. Because of its similarity to the mechanism of action of macrolides and chloramphenicol, these should not be given concomitantly, as this leads to antagonism and possible cross-resistance. In addition, when taking multiple drugs, care should be taken to see if any of the drugs also interact with the CYP3A4 and CYP3A5 enzymes. This may increase (more side effects) or decrease the effects.

Side effects

Common side effects are nausea, diarrhea, rash, and pain at the injection site. It increases the risk of hospital-acquired Clostridium difficile colitis fourfold and is therefore only recommended if other antibiotics are not suitable. Alternative antibiotics may therefore be recommended.

In rare cases, less than 0.1% of patients, clindamycin therapy has been associated with anaphylaxis, blood dyscrasias, polyarthritis, jaundice, elevated liver enzyme levels, renal dysfunction, cardiac arrest, and/or hepatotoxicity.

Use in pregnancy is possible and considered safe.

Toxicological Data

LD50 (rat, oral): 1832 mg-kg-1