Metronidazole is a versatile medication, used as an antidiarrheal and an antibiotic. As an antibiotic, it's especially powerful, able to penetrate bone and the blood-brain barrier, making it useful for treating oral and central nervous system infections. It does carry some risk of side effects, and since it may cause birth defects, pregnant cats should steer clear of it.
Bacteria that are able to live without oxygen are referred to as anaerobic. Not just any drug can combat this kind of bacteria, however metronidazole is one of the tools in your vet's arsenal when he needs a special antibiotic. Metronidazole is more than an antibiotic; it also works as an anti-inflammatory in the large intestine. Given its versatility, it's little wonder this medicine can be used for a variety of conditions. Whether it takes on protozoal infections such as giardia, is part of a cancer treatment plan or helps your cat through a bout of colitis, it's widely used by vets. There are risks of side effects, particularly if a cat takes an especially high dose, including drooling, gagging, vomiting, decreased appetite, diarrhea, lethargy, bloody or dark urine and regurgitation. Generally, cats who are taking metronidazole as an antidiarrheal don't experience side effects. Occasionally neurological side effects are seen, including head tilting, seizures, unusual eye movement and dilated pupils. It should never be given to pregnant cats, as this medicine can cause birth defects. While it's often used with other antibiotics, metronidazole may react with other drugs, including certain sedatives, anticoagulants and phenobarbital.