Marcrolides

The Macrolides are closely related antibiotics. They are different from one another in their chemical substitutions on structures of various carbon atoms and the amino and neutral sugars (see the Rat Medication Guide Index on specific drugs).

They are bacteriostatic and interfere by inhibiting protein synthesis, but in high concentrations can act as bactericidal.

Macrolides are effective against Gram-positive cocci such as streptococci, staphylococci, as well as mycobacterium, mycoplasma, chlamydia, rickettsia, and some strains of Gram-negative bacteria such as nisseria, and haemophilus. These drugs are most useful when there are allergies to the penicillins.

They are absorbed well by the GI tract, and diffuse readily through most of the bodies tissues, concentrating in lungs, spleen, liver and kidneys, but not to the cerebral spinal fluid. GI disturbances, hypersensitivity reaction, and hepatotoxicity can occur, although this is not common.

The Macrolides are concentrated in the liver and excreted in the urine and bile unchanged.