TINI

Indications

• Intestinal amoebiasis
• Urogenital trichomoniasis
• Giardiasis

Dosage

Children: For children aged 1 month to 11 years, the dosage is 50–75 mg/kg once, with a maximum of 2 g per dose. For children aged 12 to 17 years, the dosage is 2 g for a single dose, which may be repeated once if necessary.

Adults: The usual adult dosage is 2 g taken orally as a single dose for urogenital trichomoniasis or giardiasis, and 1.5 g to 2 g once daily for 3 to 6 days for intestinal amoebiasis.

Mechanism of action

Tinidazole acts as a prodrug and antiprotozoal agent. Its nitro group is reduced in Trichomonas by a ferredoxin-mediated electron transport system, generating free nitro radicals that covalently bind to DNA, causing DNA damage and cell death. The exact mechanism of action against Giardia and Entamoeba species is not fully understood but is believed to be similar to that of Trichomonas.

Pharmacodynamics

Tinidazole demonstrates in vitro and clinical activity against Trichomonas vaginalis, Giardia duodenalis (also known as G. lamblia), and Entamoeba histolytica. It does not exhibit significant activity against most strains of vaginal lactobacilli, which are beneficial bacteria in the vaginal flora.

Pharmacokinetics

Tinidazole is well absorbed following oral administration, with peak plasma concentrations occurring within 0.5 to 3 hours. It is extensively distributed throughout body tissues and fluids. The drug undergoes hepatic metabolism and is eliminated primarily through the urine, with a half-life of approximately 12 to 14 hours. Clinical and laboratory monitoring is advised if treatment extends beyond 10 days.

Adverse effects

• Abdominal pain
• Decreased appetite
• Diarrhoea
• Headache
• Nausea
• Skin reactions
• Vertigo
• Vomiting

Precautions

• Clinical and laboratory monitoring is advised if treatment exceeds 10 days

Pregnancy

Manufacturer advises avoiding use in the first trimester.

Breast-feeding

Present in milk; the manufacturer advises avoiding breastfeeding during and for 3 days after stopping treatment.

Storage

Store below 25°C, protect from moisture.

Formulations

• Tinidazole 500 mg tablets
• Tinidazole oral suspension

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.