Am Fam Physician. 2009;79(2):102-105
Author disclosure: Nothing to disclose.
Tinidazole (Tindamax), a second-generation nitroimidazole, is an antiprotozoal and antibacterial agent similar to metronidazole (Flagyl). It has a longer half-life than metronidazole (12 to 14 hours versus eight hours), allowing for a shorter course of therapy.1,2 Tinidazole has been available outside the United States for more than 25 years. In addition to being labeled for the treatment of trichomoniasis and bacterial vaginosis, it is also indicated for the treatment of giardiasis and amebiasis.
| Name | Dosage | Dose form | Cost* |
|---|---|---|---|
| Tinidazole (Tindamax) | Trichomoniasis: single 2-g oral dose | 250- and 500-mg tablets | Trichomoniasis: $18 to $31 |
| Bacterial vaginosis: 2-g oral dose once daily for two days or 1-g oral dose once daily for five days | Bacterial vaginosis: $36 to $61 (2-g dose); $46 to $76 (1-g dose) |
SAFETY
Serious adverse effects rarely reported with metronidazole and tinidazole are seizures and transient peripheral neuropathy. Like metronidazole, tinidazole can cause transient leukopenia and neutropenia. Tinidazole should not be used in patients with hypersensitivity to metronidazole. Tinidazole is U.S. Food and Drug Administration pregnancy category C (metronidazole is category B).1–3 It has not been studied in pregnant women and is contraindicated during the first trimester.1
TOLERABILITY
Adverse effects are similar to those with metronidazole, the most common of which are weakness and gastrointestinal adverse effects (e.g., metallic/bitter taste, nausea, dyspepsia, vomiting, anorexia).1,2 Nausea occurs more often with the two-day regimen.4 As with metronidazole, alcohol should be avoided during treatment with tinidazole, but for a longer period of time following the last dose (72 hours versus 24 hours). Drug interaction studies with tinidazole have not been completed; however, the same drug interactions that occur with metronidazole (e.g., increasing the activity of warfarin [Coumadin] and lithium) are likely to occur with tinidazole.1
EFFECTIVENESS
Tinidazole is as effective as metronidazole for the treatment of trichomoniasis, with both achieving high cure rates.5 In addition, in vitro studies and a few small case reports suggest that tinidazole is effective for metronidazole-resistant trichomoniasis.6–8 However, metronidazole-resistant trichomoniasis is uncommon (2 to 5 percent).3,4 Although both tinidazole regimens are more effective than placebo for the treatment of bacterial vaginosis, no research has directly compared tinidazole with metronidazole at recommended doses.4 Tinidazole has not been studied for effectiveness in treating symptoms or preventing preterm delivery in pregnant women.
PRICE
The cost of tinidazole ranges from $18 to $31 for single-dose treatment of trichomoniasis. For the treatment of bacterial vaginosis, tinidazole costs $36 to $61 for the two-day regimen and $46 to $76 for the five-day regimen. The cost of generic metronidazole ranges from $3 to $10 for the treatment of trichomoniasis (four 500-mg tablets once) and $10 to $40 for the treatment of bacterial vaginosis (one 500-mg tablet twice daily for seven days). The cost of a 70-g tube of generic metronidazole vaginal gel is $36 to $143.
SIMPLICITY
Tinidazole, like metronidazole, is prescribed as a single 2-g oral dose for the treatment of trichomoniasis. For bacterial vaginosis, the tinidazole dose is 2 g once daily for two days or 1 g once daily for five days, which is a less frequent and shorter regimen than metronidazole 500 mg twice daily for seven days. Patients should take tinidazole with food to minimize the gastrointestinal adverse effects.
Bottom Line
Tinidazole is generally an expensive alternative to metronidazole for the treatment of trichomoniasis and bacterial vaginosis. It offers little, if any, advantage with regard to safety, tolerability, and effectiveness; however, its once-daily dosing and shorter course of therapy may be useful for some patients.