Absorption

Quinolones are commonly administered PO, although forms of enrofloxacn and ciprofloxacin are available for IV, IM, and SC administration. Absorption into the blood after IM or SC delivery is rapid;

Distribution                                                                              .

The quinolones penetrate all tissues well and quickly. Particularly high concentrations are found in the kidneys, liver, and bile, but concentrations found in prostatic endometrium, and CSF are also quite notable. Most quinolones also cross the placental barrier.

Biotransformation

Some quinolones are eliminated unchanged (eg, ofloxacin), some are partially metabolized (eg cinoxacin, ciprofloxacin, enrofloxacin), Metabolites are sometimes active; enrofloxacn is de-ethylated to form ciprofloxacin.

Excretion                                                                        

Renal excretion is the major route of elimination for most quinolones. Urine concentration are often high for 24 hr after administration.

Quinolones appear in the milk of lactating animals, often at high concentrations that persist for some time.

Interactions

Antacids probably interfere with the Gl absorption of the quinolones. It also seems that nitrofurantoin impairs the efficacy of quinolones if used concurrently for urinary tract infections.