TINICURE 500MG TABLETS

Indications

• Trichomoniasis
• Giardiasis
• Amebiasis

Dosage

Children: Refer to the BNF for Children for specific paediatric dosing guidelines.

Adults: The usual recommended dose for adults is 2 grams orally as a single dose for trichomoniasis. For giardiasis, the recommended dose is 2 grams orally as a single dose. For amebiasis, the usual dose is 1.5 grams orally once daily for 3 days.

Mechanism of action

Tinidazole is a prodrug that is reduced by a ferredoxin-mediated electron transport system in Trichomonas. This reduction generates a free nitro radical, which is responsible for its antiprotozoal activity. The toxic free radicals are believed to covalently bind to DNA, causing DNA damage and ultimately leading to cell death. Although the specific mechanism against Giardia and Entamoeba species is not fully understood, it is presumed to be similar to that against Trichomonas.

Pharmacodynamics

Tinidazole exhibits activity against various protozoa, including Trichomonas vaginalis, Giardia duodenalis, and Entamoeba histolytica, both in vitro and in clinical settings. It does not demonstrate significant activity against most strains of vaginal lactobacilli, indicating a specific targeting of pathogenic protozoa.

Pharmacokinetics

Tinidazole is rapidly absorbed after oral administration, reaching peak plasma concentrations within 2 to 3 hours. It is extensively metabolized in the liver, primarily through oxidation and conjugation, with a half-life of approximately 12 to 14 hours. The drug is excreted mainly in urine, both as unchanged drug and metabolites.

Contra-indications

• Hypersensitivity to tinidazole or any component of the formulation
• History of blood dyscrasias
• Severe liver impairment

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• Dizziness
• Headache
• Metallic taste
• Dry mouth
• Peripheral neuropathy

Interactions

• Alcohol: Disulfiram-like reaction may occur, leading to flushing, tachycardia, and nausea
• Warfarin: May enhance the anticoagulant effect of warfarin
• Lithium: Increased lithium levels may occur

Precautions

• Use with caution in patients with hepatic impairment
• Monitor for signs of peripheral neuropathy, especially with prolonged use
• Avoid alcohol during treatment and for at least 48 hours after
• Assess for potential interactions with other medications

Pregnancy

Tinidazole should be avoided during pregnancy unless clearly needed. Animal studies have shown teratogenic effects.

Breast-feeding

Tinidazole is excreted in breast milk. Caution should be exercised when administering to nursing mothers.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Formulations

• Tablets: 500 mg
• Oral suspension: 100 mg/5 mL

Mechanism of action

Tinidazole is a prodrug and antiprotozoal agent. The nitro group of tinidazole is reduced in <i>Trichomonas</i> by a ferredoxin-mediated electron transport system. The free nitro radical generated as a result of this reduction is believed to be responsible for the antiprotozoal activity. It is suggested that the toxic free radicals covalently bind to DNA, causing DNA damage and leading to cell death. The mechanism by which tinidazole exhibits activity against <i>Giardia</i> and <i>Entamoeba</i> species is not known, though it is probably similar. The nitro group of tinidazole is reduced by cell extracts of Trichomonas. As a result of this reduction a free nitro radical is generated which may be responsible for the antiprotozoal activity. The mechanism by which tinidazole exhibits activity against Giardia and Entamoeba species is not known.

Pharmacodynamics

Tinidazole is a synthetic antiprotozoal agent. Tinidazole demonstrates activity both in vitro and in clinical infections against the following protozoa: <i>Trichomonas vaginalis</i>, <i>Giardia duodenalis</i> (also termed <i>G. lamblia</i>), and <i>Entamoeba histolytica</i>. Tinidazole does not appear to have activity against most strains of vaginal lactobacilli.