Lincosamides

The lincosamide class of antibiotic, mainly that of lincomycin and its derivative clindamycin, are principally bacteriostatic, but can act as bactericidal depending on concentration and organism sensitivity. The lincosamides exert action by inhibiting protein synthesis in sensitive bacteria. Spectrum and pharmacologic properties are similar to that of erythromycin but differ somewhat in chemical structure.

Lincosamides show a fairly broad spectrum of antibacterial activity against anaerobes and some limited spectrum against aerobic organisms. Most Gram-positive cocci are inhibited, but resistance is seen with some Gram-negative bacteria and strains of Clostridium difficile. It also shows some resistant to strains of Mycoplasma.

Rapidly absorbed in the gut, lincosamides distribute widely into most tissues and body fluids with the exception of cerebrospinal fluid. Minimal concentrations are found in the central nervous system in the presence of inflamed meninges. These drugs cross the placenta and are distributed in breast milk.

Lincosamides have been used to successfully treat bone and joint infections, wound infections (e.g., MRSA), abscesses, oral infections, and those respiratory infections where the organism is susceptible.

In studies clindamycin, when compared to lincomycin, shows better antibacterial activity as well as offers more complete and predictable absorption from the gastrointestinal tract, which is thought to reduce the chance of diarrhea by its use.
While lincosamides have the potential for causing fatal clostridial enterotoxemia in some species, and should avoid being administered to rabbits, hamsters, guinea pigs, horses, chinchillas or ruminating animals, the rat has shown to be very tolerant of clindamycin. However, it is strongly recommended when treating the rat to include the administration of a probiotic concurrently with clindamycin, and to continue the probiotic for two to three weeks following completion of treatment. *Note: because clindamycin is distributed in breast milk it is not recommended that it be given to animals that are nursing young due to the potential for GI effects.

Although clindamycin has been shown to cross the placenta it revealed no evidence of impaired fertility, or harm to the fetus in rats or rabbits during reproductive toxicity studies, except at doses high enough to cause maternal toxicity.¹

Finally since metabolism of lincosamides occurs in the liver, their half-life may be prolonged in the presence of hepatic disease. Caution should be used when dosing rats with known liver disorder.

References

1. Gray, J., Weaver, R., Bollert, J. and Feenstra, E., 1972. The oral toxicity of clindamycin in laboratory animals. Toxicology and Applied Pharmacology, 21(4), pp.516-531.