Ronidazoles

Ronidazoles are a group of nitroimidazole antimicrobial agents that share a common chemical core and are active against anaerobic bacteria and protozoa. The term most often refers to ronidazole itself, but the broader class includes related compounds such as metronidazole, tinidazole, ornidazole, and secnidazole, which belong to the same chemical family. Ronidazoles are used in both human and veterinary medicine, with the latter having particular prominence in some jurisdictions where ronidazole is employed to treat protozoal infections in animals.

Mechanism of action involves the selective reduction of the nitro group within anaerobic organisms, producing reactive nitro radical anions and other metabolites that damage DNA and other essential macromolecules. This interference with nucleic acid synthesis ultimately leads to inhibition of growth or death of susceptible organisms.

In humans, nitroimidazoles are used to treat a range of infections, including amoebiasis, giardiasis, trichomoniasis, and anaerobic bacterial infections such as intra-abdominal and gynecological infections. Ronidazole itself is primarily a veterinary drug and is used to treat protozoal infections such as Tritrichomonas foetus in cats and cattle; however, it carries a notable risk of neurotoxicity in cats, including ataxia and seizures, and its use is restricted in many places.

Adverse effects common to this class include gastrointestinal upset, a metallic taste, and potential neurological symptoms with higher doses or prolonged use. Alcohol interaction can produce disulfiram-like effects. Resistance can emerge in certain anaerobes and protozoa, sometimes limiting efficacy and prompting regulatory controls on veterinary use and withdrawal times for foods animals.

Overall, ronidazoles are important but tightly regulated agents, balancing broad antimicrobial activity with safety considerations.