Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.
Amaryl (Aventis)
1 mg, 2 mg and 4 mg tablets
Approved indication: type 2 diabetes
Australian Medicines Handbook Section 10.1.2
When non-insulin dependent diabetics fail to respond to weight loss and dietary modification, oral antidiabetic drugs can be added to their management. Glimepiride adds to the choice of sulfonylurea drugs for these patients. It was approved in 1996 but has only recently been marketed.
The dose of glimepiride must be titrated for each patient, depending on blood glucose measurements. Treatment begins with 1 mg daily and is increased by1 mg every 1-2 weeks. Most patients will be controlled with a dose of 4 mg or less. If higher doses are needed, there may be a benefit in dividing the dose. The maximum dose is 8 mg daily.
Usually glimepiride will be taken before breakfast. It is completely absorbed and reaches a maximum concentration within three hours. Glimepiride is completely metabolised and has a half-life of 5-8 hours. The main metabolite also has some antidiabetic effect, so, overall, the hypoglycaemic action of a single dose lasts for 24 hours. Most of the metabolites are excreted in the urine, so the drug is contraindicated in patients with severe impairment of renal or hepatic function.
Like other sulfonylureas, glimepiride releases insulin from the pancreas. This can cause hypoglycaemia, particularly in the first month of treatment. Patients and their carers should be informed about the risks of hypoglycaemia as part of their diabetes education. The most common adverse reactions, occurring in 1-2% of patients, are gastrointestinal. Many drugs may affect the hypoglycaemic action of glimepiride.
Although less is known about its long-term safety, glimepiride is probably as effective as glibenclamide when a long-acting sulfonylurea is indicated.
