tinidazole

Contraindicated in:

Hypersensitivity; cross-sensitivity with other imidazoles may occur;
Cockayne syndrome (↑ risk of hepatotoxicity and death);
Lactation: Lactation.

Use Cautiously in:

CNS pathology;
History of blood dyscrasias;
Hemodialysis (removes significant amount of tinidazole; supplement postdialysis with additional 50% of dose);
Hepatic impairment;
Unrecognized candidiasis (requires concurrent antifungal therapy);
OB: Use during pregnancy only if potential maternal benefit justifies potential fetal risk;
Pedi: Children <3 yr (safety and effectiveness not established).

Adv. Reactions/Side Effects ⬆ ⬇

GI: constipation, dyspepsia, metallic/bitter taste, vomiting

GU: ↓fertility (males)

Hemat: transient leukopenia/neutropenia

Neuro: dizziness, headache, malaise

Interactions ⬆ ⬇

Drug-drug:

↑risk of bleeding with warfarin.
Disulfiram-like reaction may occur with alcohol or propylene glycol; disulfiram should be avoided for ≥2 wk before tinidazole; alcohol should be avoided during therapy and for 3 days after therapy completed.
May ↑ levels of lithium, cyclosporine, tacrolimus, fluorouracil, and fosphenytoin (observe/monitor for toxicity if administered concurrently).
CYP3A4 inhibitors, including cimetidine or ketoconazole, may ↑ levels and risk of toxicity.
CYP3A4 inducers, including phenobarbital, rifampin, phenytoin, and fosphenytoin, may ↓ levels and effectiveness.
Absorption is ↓ by cholestyramine; separate dosing.

Availability ⬆ ⬇

(Generic available)

Tablets: 250 mg; 500 mg

Route/Dosage ⬆ ⬇

Bacterial Vaginosis

PO (Adults ): 1 g once daily for 5 days or 2 g once daily for 2 days.

Trichomoniasis

PO (Adults ): 2 g as a single dose.

Giardiasis

PO (Adults ): 2 g as a single dose.
PO (Children ≥3 yr): 50 mg/kg (up to 2 g) as a single dose;

Intestinal Amebiasis

PO (Adults ): 2 g once daily for 3 days.
PO (Children ≥3 yr): 50 mg/kg once daily for 3 days.

Amebic Liver Disease

PO (Adults ): 2 g once daily for 3–5 days.
PO (Children ≥3 yr): 50 mg/kg once daily for 3–5 days.

US Brand Names ⬆ ⬇

Action ⬆ ⬇

Interaction with protozoa results in release of a free nitro radical that has antiprotozoal activity.

Therapeutic effects:

Resolution of protozoal infections.

Spectrum:

Active against Bacteroides spp., Entamoeba histolytica, Gardnerella vaginalis, Giardia duodenalis (also known as Giardia lamblia), Prevotella spp., and Trichomonas vaginalis.

Classifications ⬆ ⬇

Therapeutic Classification: antiprotozoals

Pharmacologic Classification: imidazoles

Pharmacokinetics ⬆ ⬇

Absorption: Rapidly and completely absorbed following oral administration.

Distribution: Extensively distributed.

Metabolism/Excretion: Primarily metabolized by the liver via the CYP3A4 isoenzyme; 20–25% excreted unchanged in urine, 12% excreted in feces.

Half-Life: 12–14 hr.

Time/Action Profile ⬆ ⬇

(plasma concentrations)

ROUTE	ONSET	PEAK	DURATION
PO	rapid	2 hr	24 hr

Patient/Family Teaching ⬆ ⬇

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.
Rep: Advise females of reproductive potential to inform health care professional if pregnancy is planned or suspected and to avoid breastfeeding during and for 72 hr after taking tinidazole. May impair fertility in males.

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Indications ⬇

Contraind./Precautions ⬆ ⬇