Ornidazole

Oral
Amoebic dysentery

Oral
Giardiasis

Oral
Prophylaxis of postoperative anaerobic bacterial infections

Oral
Amoebiasis

Oral
Trichomoniasis

Patients receiving haemodialysis: Give an additional dose of 500 mg (if the daily dose is 2 g daily) or 250 mg (if the daily dose is 1 g daily) before each dialysis.

Severe: Double the interval between doses.

Should be taken with food.

Hypersensitivity.

Patient with CNS disease (e.g. multiple sclerosis, epilepsy). Patient undergoing haemodialysis. Hepatic impairment. Children. Pregnancy and lactation.

Blood and lymphatic system disorders: Rarely, leucopenia.
Ear and labyrinth disorders: Very rarely, vertigo.
Gastrointestinal disorders: Nausea, vomiting, diarrhoea, epigastric discomfort, dry mouth. Rarely, impaired sense of taste.
General disorders and administration site conditions: Fatigue.
Hepatobiliary disorders: Jaundice.
Investigations: Abnormal LFT.
Metabolism and nutrition disorders: Loss of appetite.
Nervous system disorders: Very rarely, somnolence, headache, dizziness, tremor, rigidity, coordination impairments, seizures, temporary loss of consciousness, sensory or mixed peripheral neuropathy.
Skin and subcutaneous tissue disorders: Rarely, pruritus and skin reactions.

This drug may cause somnolence, dizziness, or temporary loss of consciousness, if affected, do not drive or operate machinery.

Potentiates the effect of coumarin-type oral anticoagulants. Prolongs the muscle relaxant effect of vecuronium bromide.

Disulfiram-like reaction (e.g. flushing, tachycardia) may occur when taken concomitantly with alcohol.

Description: Ornidazole, a 5-nitroimidazole derivative, acts via a mechanism that involves preactivation by reduction of the nitro group and production of toxic derivatives and radicals. It is effective against protozoa, such as Trichomonas vaginalis, Entamoeba histolytica and Giardia lamblia (Giardia intestinalis), and certain anaerobic bacteria, such as Bacteroides and Clostridium spp., Fusobacterium spp., and anaerobic cocci.
Pharmacokinetics:
Absorption: Rapidly absorbed. Time to peak plasma concentration: Within 3 hours.
Distribution: Widely distributed in body fluids and tissues, including the CSF. Plasma protein binding: Approx 13%.
Metabolism: Metabolised in the liver.
Excretion: Via urine (4% as unchanged drug). Elimination half-life: Approx 13 hours.

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 28061, Ornidazole. https://pubchem.ncbi.nlm.nih.gov/compound/Ornidazole. Accessed May 26, 2022.

Store at ≤30°C. Protect from light.

Antiamoebics / Other Antibiotics

J01XD03 - ornidazole ; Belongs to the class of imidazole derivative antibacterials. Used in the systemic treatment of infections.
P01AB03 - ornidazole ; Belongs to the class of nitroimidazole derivatives antiprotozoals. Used in the treatment amoebiasis and other protozoal diseases.

Marcus Y, Tal N, Ronen M et al. The Drug Ornidazole Inhibits Photosynthesis in a Different Mechanism Described for Protozoa and Anaerobic Bacteria. Biochem J. 2016 Dec;473(23):4413-4426. doi: 10.1042/BCJ20160433. Accessed 11/03/2022. PMID: 27647935

Anon. Ornidazole. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 09/03/2022.

Buckingham R (ed). Ornidazole. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 09/03/2022.

Preston CL (ed). Ornidazole Drug Interactions. Stockley’s Drug Interactions [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 11/03/2022.

Teva Pharma (New Zealand) Limited. Arrow - Ornidazole, 500 mg, Film Coated Tablet data sheet 18 October 2018. Medsafe. http://www.medsafe.govt.nz. Accessed 09/03/2022.