Tinidazole

INTRODUCTION

Indications

Bacterial vaginosis; Trichomoniasis; Giardiasis; Amebiasis.

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 Trichomonas vaginalis, Giardia duodenalis (also known as G. lamblia), and Entamoeba histolytica.

Adverse Reactions/Side Effects

CNS: dizziness, headache, malaise. GI: constipation, dyspepsia, metallic/bitter taste, vomiting. Hemat: transient leukopenia/neutropenia.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Assess dizziness that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician, and caution the patient and family/caregivers to guard against falls and trauma.

• Monitor signs of leukopenia/neutropenia, including fever, sore throat, and signs of infection. Notify physician if these signs do not improve spontaneously.

Interventions

• Always wash hands thoroughly and disinfect equipment (whirlpools, electrotherapeutic devices, treatment tables, and so forth) to help prevent the spread of infection. Use universal precautions or isolation procedures as indicated for specific patients.

Patient/Client-Related Instruction

• Advise patient to report bothersome side effects such as severe or prolonged headache or GI reactions (nausea, vomiting, constipation, indigestion, altered taste).

Pharmacokinetics

Absorption: Rapidly and completely absorbed following oral administration.

Distribution: Extensively distributed; crosses placenta and blood-brain barrier, enters breast milk.

Metabolism and Excretion: Mostly metabolized (CYP3A4 enzyme system); 20–25% excreted unchanged in urine, 12% excreted in feces.

Half-life: 12–14 hr.

Contraindications/Precautions

Contraindicated in: Hypersensitivity; cross sensitivity with other imidazoles may occur; 1st trimester of pregnancy; Lactation.

Use Cautiously in: CNS pathology; History of blood dyscrasia; Hemodialysis (removes significant amount of tinidazole; supplement postdialysis with additional 50% of dose); Hepatic impairment; Unrecognized candidiasis (requires concurrent antifungal therapy); Children younger than 3 yr (safety not established).

Interactions

Drug-Drug: ↑ risk of bleeding with warfarin. Disulfiram-like reaction may occur with alcohol or propylene glycol; disulfiram should be avoided for at least 2 wk before tinidazole. May ↑ level of lithium, cyclosporine, tacrolimus, fluorouracil, and intravenous fosphenytoin (observe/monitor for toxicity if administered concurrently). Drugs that induce to CYP450 liver enzyme system (phenobarbital, rifampin, phenytoin, or fosphenytoin) may ↓ levels and effectiveness. Drugs that inhibit to CYP450 liver enzyme system (cimetidine or ketoconazole) may ↑ levels. Oxytetracycline may ↓ effectiveness. Absorption is ↓ by cholestyramine; separate dosing.