Classifications: azole antibiotic; antiprotozoal; amebicide;
Therapeutic: azole antibiotic
; antiprotozoal; amebicide
Prototype: Metronidazole
Pregnancy Category: D first trimester; C second and third trimester


250 mg, 500 mg tablets


Made from cell extracts of Trichomonas. Tinidazole is effective against dividing and nondividing cells of targeted bacteria and protozoa. It inhibits formation of their DNa helix and thus inhibits DNA synthesis of these organisms. This leads to bacterial and protozoal cell death.

Therapeutic Effect

Demonstrates activity against infections caused by protozoa and anaerobic bacteria.


Treatment of trichomoniasis, giardiasis, amebiasis, bacterial vaginosis, and amebic liver abscess.


First trimester of pregnancy (category D), second and third trimesters pregnancy (category C); known hypersensitivity to tinidazole or other azole antibiotics (e.g., metronidazole); lactation within 72 h of tinidazole use; children <3 y.

Cautious Use

CNS diseases, liver dysfunction, alcoholism, ethanol intoxication; hematologic disease; neurologic disease; bone marrow depression; dialysis; candidiasis.

Route & Dosage

Adult: PO 2 g as single dose
Child (≥ 3 y): PO 50 mg/kg (up to 2 g) as single dose

Intestinal Amebiasis
Adult: PO 2 g once daily for 3 d
Child (≥ 3 y): PO 50 mg/kg/d (up to 2 g/d) once daily for 3 d

Amebic Liver Abscess
Adult: PO 2 g once daily for 3–5 d
Child (≥3 y): PO 50 mg/kg/d (up to 2 g/d) once daily for 3–5 d

Adult: PO 2 g as single dose

Bacterial Vaginosis
Adult: PO 2 g q.d. x 2 d OR 1 g q.d. x 5 d

Hemodialysis: If dose given on dialysis day, give supplemental dose (? regular dose) post-dialysis


  • Give with food to minimize GI distress; may be crushed in artificial cherry syrup if tablets cannot be swallowed whole.
  • If given on a dialysis day, add a 50% dose of tinidazole at the end of hemodialysis.
  • Separate the dosing of cholestyramine and tinidazole by 2–4 h when used concurrently.
  • Do not give within 2 wk of the last dose of disulfiram.
  • Store at 15°–30° C (59°–86° F). Protect from light.

Adverse Effects (≥1%)

Body as a Whole: Weakness, fatigue, malaise. CNS: Dizziness, headache. GI: Metallic/bitter taste, nausea, anorexia, dyspepsia, cramps, epigastric discomfort, vomiting, constipation.


Drug: May increase INR with warfarin; alcohol may cause disulfiram-like reaction; may increase the half-life of fosphenytoin, phenytoin; may increase levels and toxicity of lithium, fluorouracil, cyclosporine, tacrolimus; cholestyramine may decrease absorption of tinidazole; cimetidine or ketoconazole may increase levels.


Peak: 2 h. Distribution: Crosses blood–brain barrier and placenta and is excreted in breast milk. Metabolism: In the liver by CYP3A4. Elimination: Primarily in urine. Half-Life: 12–14 h.

Nursing Implications

Assessment & Drug Effects

  • Withhold drug and notify physician for S&S of CNS dysfunction (e.g., seizures, numbness or paresthesia of extremities). Drug should be discontinued if abnormal neurological signs appear.
  • Lab tests: baseline LTFs; CBC with differential, if retreatment is required.
  • Monitor INR/PT frequently with concomitant oral anticoagulants. Continue monitoring for at least 8 d after discontinuation of tinidazole.
  • Monitor serum lithium levels with concurrent use.
  • Monitor for phenytoin toxicity with concurrent IV phenytoin.

Patient & Family Education

  • Stop taking the drug and report promptly: convulsions, numbness, tingling, pain, or weakness in the hands or feet; dizziness or unsteadiness; fever.
  • Harmless urine discoloration may occur while taking this drug.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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