Tinidazole

Tinidazole is a nitroimidazole antiprotozoal and antibacterial drug with activity related to that of metronidazole. Veterinary use is extra-label and includes selected Giardia and anaerobic infections. Much of the clinical experience comes from small studies or extrapolation, and effectiveness differs among protozoal species and treatment regimens.

Group

Nitroimidazole antiprotozoal

Mechanism of Action

Tinidazole enters susceptible organisms and undergoes reductive activation in low-redox intracellular environments. Reactive nitro intermediates damage DNA and other essential cellular targets, impairing replication and survival. Dependence on this activation pathway accounts for activity against selected protozoa and anaerobic bacteria.

Dose Rates

Dogs

Use / stage	Dose	Route	Schedule	Instructions
Giardiasis	15 mg/kg	PO	Every 12 h	Up to 5 days
Susceptible anaerobic infection	15 mg/kg	PO	Every 12 h
Stomatitis or anaerobic infection	15–25 mg/kg	PO	Every 12 h	Up to 7 days
Giardiasis alternative	44 mg/kg	PO	Every 24 h	Up to 6 days; Separate higher reported course; monitor neurological tolerance.

Cats

Use / stage	Dose	Route	Schedule	Instructions
Giardiasis	15 mg/kg	PO	Every 24 h	Up to 5 days
Susceptible anaerobic infection	15 mg/kg	PO	Every 24 h	Some anaerobic conditions require more than 5 days; no universal duration supplied.
Stomatitis or anaerobic infection	15 mg/kg	PO	Every 24 h	Up to 7 days

Horses

Use / stage	Dose	Route	Schedule	Instructions
Reported protozoal or anaerobic infection	10–15 mg/kg	PO	Every 12 h

Indications

Extra-label treatment of selected Giardia infections in dogs and cats, with limited regimen-specific clinical evidence.
Treatment of selected susceptible anaerobic infections, including some oral or soft-tissue infections in small animals.

Contraindications

Pregnancy
Seizure susceptibility
Known metronidazole sensitivity

Interactions

Can potentiate warfarin and cyclosporine by inhibiting metabolism.

Adverse effects

Nausea, vomiting, anorexia; high exposure may cause ataxia, tremor, nystagmus or seizures.

Toxicity

Neurological toxicity resembles metronidazole toxicity; benzodiazepines have been used for associated CNS signs. Animal overdose evidence is limited; manage neurologic and other clinical effects supportively. Human dialysis data are not a validated animal protocol.

Preparations

Preparation	Form	Strength	Route
Tinidazole 250 mg	Tablet	250 mg / tablet	PO
Tinidazole 500 mg	Tablet	500 mg / tablet	PO

Monitoring and Administration

Give with food to limit nausea and bitterness; observe neurological function. Flavored tablet suspensions have reported stability of 7 days.