Metformin dosage

Individualize dosage on the basis of efficacy and tolerance, while not exceeding the maximum recommended daily dose of metformin IR 2,550 mg in adults and 2,000 mg in children (10 to 16 years of age) the maximum recommended daily dose of metformin ER in adults is 2,000 mg (2,500 mg with Fortamet). Give metformin IR in divided doses with meals and give metformin ER once daily with the evening meal. Start at a low dose, with gradual dose escalation, to reduce Gl side effects and... 

Conversion from metformin IR to ER-A randomized trial s results suggest that patients receiving metformin IR may be safely switched to metformin ER once daily at the same total daily dose, up to 2,000 mg once/day. Following a switch, closely monitor glycemic control and make dosage adjustments accordingly. 

Children The usual starting dose of metformin IR is 500 mg twice a day, given with meals. Make dosage increases in increments of 500 mg/week up to a maximum of 2,000 mg/day given in divided doses. 

Special patient populations Initial and maintenance dosing should be conservative in patients with advanced age because of the potential for decreased renal function. Base any dosage adjustment on a careful assessment of renal function. Generally, do not titrate elderly, debilitated, or malnourished patients to the maximum dose. Do not initiate metformin IR and ER treatment in patients 80 years of age and older unless measurement of Ccr demonstrates that renal function is not reduced. 

Eideriy Because aging is associated with reduced renal function, use metformin with caution as age increases. Generally, do not titrate elderly patients to the maximum dose of metformin (see Administration and Dosage). 

Renal impairment - Metformin is contraindicated in patients with renal impairment. Therefore, concomitant administration of rosiglitazone and metformin is contraindicated in these patients. However, no dosage adjustment is necessary when rosiglitazone is used as monotherapy in patients with renal impairment. 

Diabetes mellitus, combination therapy PO With insulin Initially, 15-30 mg once a day. Initially, continue current insulin dosage then decrease insulin dosage by 10% to 25% if hypoglycemia occurs or plasma glucose level decreases to less than 100 mg/dl. Maximum 45 mg/day. With sulfonylureas Initially, 15-30 mg/day. Decrease sulfonylurea dosage if hypoglycemia occurs. With metformin Initially, 15-30 mg/day. As monotherapy Monotherapy is not to be used if patient is well controlled with diet and exercise alone. Initially, 15-30 mg/day. May increase dosage in increments until 45 mg/day is reached. 

Metformin Recommended starting dosage is 500 mg BID with meals... 

A 65-year-old man with a creatinine clearance of 67 ml/minute taking metformin 850 mg bd developed lactic acidosis (lactate 25 mmol/1, pH 7.13, bicarbonate 5 mmol/1) (48). Despite the relatively small dosage of metformin, he had unexplained very high metformin concentrations (61 ig/ml). 

A 52-year-old woman took glipizide and enalapril and then, because of persistent hyperglycemia, metformin 1000 mg/day (103). Her liver enzymes were normal, and after 2 weeks the dosage of metformin was increased to 2000 mg/day. Two weeks later she became icteric and her bilirubin and liver enzymes were increased. Serological studies were negative. All drugs were withdrawn. A liver biopsy was consistent with... 

Modified-release formulations of metformin allow once daily dosage. In a double-blind, parallel-group comparison of an immediate-release and an extended-release formulation in 191 patients for 24 weeks adverse events did not differ between the groups (125). 

Gregorio F, Ambrosi F, Manfrini S, Velussi M, Carle F, Testa R, Merante D, Filipponi P. Poorly controlled elderly Type 2 diabetic patients the effects of increasing sulpho-nylurea dosages or adding metformin. Diabet Med 1999 16(12) 1016-24. 

The fed state, and the known ability to retain solid oral dose forms in this state, has been exploited using a relatively traditional approach of swelling tablets [32]. These dosage forms, based on the swelling of hydrocolloids such as hydroxypropylcellulose, are retained in the stomach for several hours and are capable of releasing ciprofloxacin or metformin over an extended period of time whereas the dosage forms are retained in the fed stomach [33]. 

Examples of some drugs whose activity is increased in liver disease include oral anticoagulants, metformin, chloramphenicol, NSAIDs and sulphonylureas. It is well known that drugs such as opioids should be used in reduced dosage in patients with hepatic dysfunction doses need to be titrated, Therefore, if adverse drug interactions with opioids occur in patients with liver dysfunction, the consequences such as respiratory depression could be life-threatening,... 

A reverse-phase HPLC procedure was proposed as a suitable method for the simultaneous determination of metformin and glibenclamide in a combined dosage form. The chromatographic conditions were adjusted to provide adequate retention and resolution of metformin and glibenclamide. A mixture of buffer and acetonitrile, in... 

The described isocratic HPLC method is validated and shown to be precise and accurate. This method can be used in quality control departments for the simultaneous determination of metformin and glibenclamide in the combined dosage form. 

Vasudevan, M. Ravi, J. Ravisankar, S. Suresh, B g Ion-pair liquid chromatography technique for the estima- tion of metformin in its multicomponent dosage forms. J. Pharm. Biomed. Anal. 2001, 25, 77-84. 

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