ronidazole

Ronidazole is a nitroimidazole antimicrobial agent used primarily in veterinary medicine to treat protozoal infections. It is closely related to metronidazole but differs in spectrum and regulatory status. In cats, ronidazole has been used to treat Tritrichomonas foetus–associated colitis, a cause of chronic diarrhea; laboratory studies have shown activity against other protozoa such as Giardia and Entamoeba, but clinical results in humans are limited.

Ronidazole's mechanism involves reduction to active metabolites in anaerobic organisms, causing DNA damage and parasite death. It is generally administered orally, with absorption and distribution described for several species, followed by hepatic metabolism and renal excretion.

Safety considerations limit its use. Adverse effects include neurotoxicity (ataxia, tremors, seizures) in some animals, particularly with longer courses or higher doses, and possible hepatotoxicity. Because of these risks, ronidazole is used with caution and under veterinary supervision; it is not approved for routine human use in many jurisdictions and may be restricted for food-producing animals due to residue concerns.

Regulatory status varies by country. When available, it is dispensed by veterinarians, with monitoring for adverse effects and dose adjustments based on species and condition. See also nitroimidazole class and metronidazole.