Ornidazole

Indications

Ornidazole is used for: Amoebiasis, Hereditary angioedema, Trichomoniasis, Anaerobic bacterial infections, Amoebic dysentery, Surgical Prophylaxis,

Adult Dose

Oral Amoebiasis Adult: 0.5 g bid for 5-10 days. Amoebic dysentery Adult: 1.5 g as a single daily dose for 3 days. Alternatively for patients >60 kg: 1 g bid for 3 days. Giardiasis Adult: 1-1.5 g as a single daily dose for 1-2 days. Trichomoniasis Adult: 1.5 g as a single daily dose or 0.5 g bid for 5 days. Treat sexual partners concomitantly. Hepatic impairment: Severe: Double the interval between doses.

Child Dose

Oral Amoebiasis Child: 25 mg/kg as a single daily dose for 5-10 days. Amoebic dysentery Child: 40 mg/kg daily. Giardiasis Child: 30-40 mg/kg daily. Trichomoniasis Child: 25 mg/kg as a single dose.

Renal Dose

Renal impairment: Haemodialysis patients: Give a supplemental dose (50% of the usual dose) before dialysis.

Administration

Should be taken with food.

Contra Indications

Hypersensitivity to ornidazole or to other nitroimidazole derivatives.

Precautions

Renal and hepatic impairment. CNS diseases e.g. epilepsy or multiple sclerosis. May impair ability to drive or operate machinery. Pregnancy and lactation.

Pregnancy-Lactation

Interactions

May decrease absorption of oral fat-soluble vitamins, amiodarone, propafenone. May decrease plasma levels of ciclosporin. May alter the effects of warfarin (monitor INR). May elevate plasma levels of pravastatin.

Adverse Effects

Side effects of Ornidazole : Somnolence, headache, nausea, vomiting, dizziness, tremor, rigidity, poor coordination, seizures, tiredness, vertigo, temporary loss of consciousness and signs of sensory or mixed peripheral neuropathy, taste disturbances, abnormal LFTs, skin reactions.

Mechanism of Action

Ornidazole is a 5-nitroimidazole derivative active against protozoa and anaerobic bacteria. It is converted to reduction products that interact with DNA to cause destruction of helical DNA structure and strand leading to a protein synthesis inhibition and cell death in susceptible organisms.