Tinidazole is a second-generation 5-nitroimidazole antimicrobial agent with potent activity against anaerobic bacteria and protozoa. It is structurally and functionally similar to metronidazole but offers a longer half-life, allowing for simpler, shorter-duration dosing regimens. It is widely used in India for the treatment of amoebiasis, giardiasis, trichomoniasis, and anaerobic bacterial infections.
Adult: **Amoebiasis:** Intestinal: 2g once daily for 3 days. Hepatic (abscess): 2g once daily for 3-5 days. **Giardiasis:** 2g single dose. **Trichomoniasis:** 2g single dose (or 500mg BD for 7 days). **Anaerobic Infections:** 2g loading dose on day 1, then 1g once daily for 5-6 days.
Note: Take orally with or after food to minimize gastrointestinal upset. Tablets should be swallowed whole with a full glass of water. For single 2g dose, four 500mg tablets are taken together.
Tinidazole is a prodrug. Its nitro group is reduced intracellularly by low-redox potential electron transport proteins (ferredoxin, flavodoxin) found in anaerobic microorganisms. This reduction generates cytotoxic intermediates (short-lived nitro radical anions and nitroso derivatives) that cause DNA strand breaks, inhibition of nucleic acid synthesis, and ultimately cell death.
Pregnancy: **Category C (US FDA).** Contraindicated in first trimester. Avoid in second/third trimester unless potential benefit justifies potential fetal risk. Crosses placenta.
Driving: May cause dizziness, vertigo, ataxia, or confusion. Patients should be cautioned about operating machinery or driving until they are certain the drug does not affect them adversely.
| Alcohol (Ethanol) | Disulfiram-like reaction: severe nausea, vomiting, flushing, tachycardia, hypotension. | Major |
| Warfarin & other Coumarin Anticoagulants | Tinidazole may inhibit metabolism, potentiating anticoagulant effect and increasing INR/bleeding risk. | Major |
| Phenobarbital, Phenytoin | May induce metabolism of tinidazole, reducing its plasma concentration and efficacy. | Moderate |
| Lithium | Potential for increased lithium levels and toxicity; monitor serum lithium. | Moderate |
| Cyclosporine, Tacrolimus | Tinidazole may increase levels of these calcineurin inhibitors, increasing risk of nephrotoxicity. | Moderate |
| Fluorouracil (5-FU) | Tinidazole may reduce clearance of 5-FU, increasing toxicity. | Moderate |