Consumer medicine information

1 Name of Medicine

Metronidazole benzoate.

2 Qualitative and Quantitative Composition

Flagyl S suspension 6.4% w/v (metronidazole 200 mg/5 mL) contains 320 mg of metronidazole benzoate, equivalent to 200 mg of metronidazole, per 5 mL.
Metronidazole benzoate is 1-(2-benzoyloxyethyl)-2-methyl-5-nitroimidazole.
List of excipients with known effect. Hydroxybenzoates, sugars.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

A white or cream suspension with a slight yellow tinge, and with an odour of orange and lemon.

4 Clinical Particulars

4.9 Overdose

Symptoms. Overdosage with metronidazole appears to be associated with very few abnormal signs or symptoms. Disorientation, ataxia and vomiting may occur, especially after ingestion of large amounts. In case of suspected massive overdosages, a symptomatic and supportive treatment should be instituted.
Single oral doses of metronidazole, up to 12 g, have been reported in suicide attempts and accidental overdoses.
Treatment. There is no specific antidote for metronidazole overdosage. In cases of suspected overdosage, a symptomatic and supportive treatment should be instituted.
For information on the management of overdose, contact the Poison Information Centre on 131126 (Australia) or the National Poisons Centre, 0800 POISON or 0800 764 766 (New Zealand).

5 Pharmacological Properties

Metronidazole benzoate itself is not systemically available following oral administration. It is hydrolysed before or during absorption through the gut wall so that only metronidazole can be detected in the circulation.

5.3 Preclinical Safety Data

Genotoxicity. In studies on the mutagenic potential of metronidazole, the Ames test was positive while several nonbacterial tests in animals were negative. In the patients with Crohn's disease, metronidazole increased the chromosome abnormalities in circulating lymphocytes. The use of metronidazole for longer treatment than usually required should be carefully weighed (see Section 4.4 Special Warnings and Precautions for Use) and the benefit/ risks should, therefore, be carefully assessed in each case particularly in relation to the severity of the disease and the age of the patient.
Carcinogenicity. Metronidazole been shown to be tumorigenic and carcinogenic in rodents.

6 Pharmaceutical Particulars

6.7 Physicochemical Properties

Chemical structure.
https://stagingapi.mims.com/au/public/v2/images/fullchemgif/CSMETBEN.gif CAS number. 13182-89-3.
Slightly yellow crystalline powder with a melting point of 99 to 102°C. Solubility at 25°C (g/100 mL solvent): 12.2 x 10^-3 in water, 2 in ethanol, 5 in methanol and 25.6 in acetone. The pH of metronidazole benzoate suspensions in water is 5 to 6.5.

7 Medicine Schedule (Poisons Standard)

Schedule 4. Prescription Only Medicine.

Summary Table of Changes

https://stagingapi.mims.com/au/public/v2/images/fulltablegif/FLAGYSST.gif