Dymetrazole Mechanism of Action

Pharmacology: Actions: Specific bactericidal activity against important obligate anaerobes.
Pharmacokinetics: Metronidazole is readily and most completely absorbed after oral doses. Peak plasma concentrations of about 6 and 12 micrograms/mL are achieved, usually within 1 to 2 hours, after single doses of 250 and 500 mg respectively. Some accumulation occurs and consequently there are higher concentrations when multiple doses are given. Absorption may be delayed but is not reduced overall by food. Metronidazole benzoate given by mouth is hydrolyzed in the gastrointestinal tract to release metronidazole which in turn is then absorbed.
Metronidazole is widely distributed. It appears in most body tissues and fluids including bile, bone, breast milk, cerebral abscesses, CSF, liver and liver abscesses, saliva, seminal fluids, and vaginal secretions, and achieves concentration similar to those in plasma. It also crosses the placenta and rapidly enters the fetal circulations. No more than 20% is bound to plasma proteins.
The elimination half-life of metronidazole is about 8 hours; that of the hydroxy metabolite is slightly longer. The half-life of metronidazole is reported to be longer in neonates and in patients with severe hepatic impairment; that of the hydroxy metabolite is prolonged in patients with substantial renal impairment. The majority of a dose of metronidazole is excreted in the urine, mainly as metabolites; a small amount appears in the feces.