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Pharmacologic class: Antiprotozoal
Therapeutic class: Anti-infective
Pregnancy risk category C
FDA Box Warning
Prolonged use of metronidazole (a structurally related drug with similar biologic effects) has caused cancer in mice and rats. Reserve tinidazole for conditions listed under "Indications and dosages."
Free nitro radical (generated from tinidazole reduction by Trichomonas cell extracts) may explain activity against Trichomonas species; activity against Giardia and Entamoeba species is unknown.
Tablets: 250 mg, 500 mg
⊘Indications and dosages
➣ Trichomoniasis caused by Trichomonas vaginalis
Adults: Single dose of 2 g P.O. with food, given to both sexual partners simultaneously
➣ Bacterial vaginosis in nonpregnant females
Adults: 2 g P.O. once daily with food for 2 days, or 1 g P.O. once daily with food for 5 days
➣ Giardiasis caused by Giardia duodenalis (Giardia lamblia)
Adults: Single dose of 2 g P.O. with food
Children older than age 3: Single dose of 50 mg/kg (up to 2 g) with food
➣ Amebiasis caused by Entamoeba histolytica
Adults: 2 g P.O. daily with food for 3 days
Children older than age 3: 50 mg/kg (up to 2 g) P.O. daily with food for 3 days
➣ Amebic liver abscess caused by E. histolytica
Adults: 2 g P.O. daily with food for 3 to 5 days
Children older than age 3: 50 mg/kg (up to 2 g) P.O. daily with food for 3 to 5 days
• Hemodialysis patients
• Hypersensitivity to drug, its components, or other nitroimidazole derivatives
• First trimester of pregnancy
Use cautiously in:
• CNS disease, hepatic dysfunction
• history of blood dyscrasias
• elderly patients
• pregnant or breastfeeding patients
• children (except to treat giardiasis and amebiasis in children older than age 3).
• Give with food to minimize GI discomfort.
CNS: weakness, fatigue, malaise, dizziness, vertigo, ataxia, insomnia, drowsiness, giddiness, headache, transient peripheral neuropathy, seizures
GI: nausea, vomiting, diarrhea, constipation, dyspepsia, gastric discomfort, tongue discoloration, stomatitis, anorexia
Hematologic: transient neutropenia and leukopenia
Musculoskeletal: arthralgia, myalgia, arthritis
Other: altered taste, overgrowth of susceptible organisms, hypersensitivity reactions including angioedema
Drug-drug. Cyclosporine, lithium, tacrolimus: possible increase in blood levels of these drugs
Cholestyramine: decreased oral bioavailability of tinidazole
CYP450 inducers (such as phenobarbital, rifampin): increased tinidazole elimination and decreased blood level
CYP450 inhibitors (such as cimetidine, ketoconazole): increased tinidazole blood level
Fluorouracil: decreased fluorouracil clearance
Fosphenytoin, phenytoin: prolonged half-life and reduced clearance of these drugs
Oxytetracycline: antagonism of therapeutic effects of tinidazole
Warfarin, other oral coumarin anticoagulants: increased effects of these drugs
Drug-diagnostic tests. Alanine aminotransferase, aspartate aminotransferase, hexokinase glucose, lactate dehydrogenase, triglycerides: interference with test results
Drug-behaviors. Alcohol use: disulfiram-like reaction during tinidazole therapy and for 3 days after
Closely monitor patient for neurologic abnormalities, such as seizures and peripheral neuropathy. If these occur, withdraw drug immediately.
Time/action profile (blood levels)
|PO||rapid||2 hr||24 hr|
Adverse Reactions/Side Effects
Central nervous system
- metallic/bitter taste
- transient leukopenia/neutropenia
Drug-Drug interaction↑ risk of bleeding with warfarin.Disulfiram-like reaction may occur with alcohol or propylene glycol ; disulfiram should be avoided for at least 2 weeks before tinidazole.May ↑ levels of lithium, cyclosporine, tacrolimus, fluorouracil, and fosphenytoin (observe/monitor for toxicity if administered concurrently).Drugs that induce the CYP450 liver enzyme system (phenobarbital, rifampin, phenytoin or fosphenytoin ) may ↓ levels and effectiveness.Drugs that inhibit the CYP450 liver enzyme system (cimetidine or ketoconazole ) may ↑ levels.Absorption is ↓ by cholestyramine ; separate dosing.
Availability (generic available)
- Assess patient for symptoms of infection (discharge, itching) prior to and during therapy.
- Monitor neurologic status during and after IV infusions. Inform health care professional if numbness, paresthesia, weakness, ataxia, or convulsions occur.
- Giardiasis: Monitor three stool samples taken several days apart, beginning 3–4 wk after treatment.
- Lab Test Considerations: May cause transient leukopenia and neutropenia. Monitor total and differential leukocyte counts if retreatment is necessary.
- May interfere with certain tests of serum chemistry values such as AST, ALT, LDH, triglycerides, and glucose hexokinase.
Potential Nursing DiagnosesRisk for infection (Indications)
- Symptoms of known or previously unrecognized candidiasis may become worse during therapy and require treatment with an antifungal agent.
- Oral: Administer with food to decrease GI upset. May be crushed and prepared as a suspension in cherry syrup by pharmacist for patients unable to swallow tablets. Shake well before administering.
- Instruct patient to take medication as directed, even if feeling better. Do not skip doses or double up on missed doses. If a dose is missed, take as soon as remembered if not almost time for next dose.
- Advise patients treated for trichomoniasis that sexual partners may be asymptomatic sources of reinfection and should be treated concurrently. Patient should also refrain from intercourse or use a condom to prevent reinfection.
- Caution patient to avoid intake of alcoholic beverages or preparations containing alcohol during and for at least 3 days after treatment with tinidazole. May cause a disulfiram-like reaction (flushing, nausea, vomiting, headache, abdominal cramps).
- May cause dizziness or drowsiness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
- Inform patient that medication may cause an unpleasant metallic taste.
- Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
- Advise patient to inform health care professional if pregnancy is suspected or if breastfeeding before taking this medication.
- Resolution of signs and symptoms of infection.