Metformin dosing

AMILORIDE METFORMIN T metformin levels and risk of lactic acidosis Metformin is not metabolized in humans and is not protein-bound. Competition for renal tubular excretion is the basis for t activity or retention of metformin Theoretical possibility. Requires reduction of metformin dose to be considered, or the avoidance of co-administration... 

H2 RECEPTOR BLOCKERS METFORMIN t level of metformin and risk of lactic acidosis. The onset of lactic acidosis is often subtle with symptoms of malaise, myalgia, respiratory distress and t non-specific abdominal distress. There may be hypothermia and resistant bradyarrhythmias Metformin is not metabolized in humans and is not protein bound. Competition for renal tubular excretion is the basis for t activity or retention of metformin. Cimetidine competes for excretory pathway Theoretical possibility. Requires 1 metformin dose to be considered or to avoid co-administration. Warn patients about hypoglycaemia >- For signs and symptoms of hypoglycaemia, see Clinical Features of Some Adverse Drug Interactions, Hypoglycaemia... 

BIGUANIDES. The nurse gives metformin two or three times a day with meals. If the patient has not experienced a response in 4 weeks using the maximum dose of metformin, the primary care giver may add an oral sulfonylurea while continuing metformin at the maximum dose. Glucophage XR (metformin extended release) is administered once daily with the evening meal. 

Primary side effects associated with metformin therapy are gastrointestinal in nature, including decreased appetite, nausea, and diarrhea. These side effects can be minimized through slow titration of the dose and often subside within 2 weeks. Discontinuation because of side effects occurs in only 3% to 5% of patients. 

Metformin immediate-release is usually initiated at 500 mg twice daily with the largest meals and increased by 500 mg weekly until glycemic goals or 2,000 mg/day is achieved. Metformin 850 mg can be dosed once daily and then increased every 1 to 2 weeks to a maximum of 850 mg three times daily (2,550 mg/day). 

Patient management Monitor long-term efficacy by measurement of HbA- c levels approximately every 3 months. When hypoglycemia occurs in patients taking a combination of repaglinide and a thiazolidinedione or repaglinide and metformin, reduce the dose of repaglinide. 

Monotherapy and combination with metformin or a thiazolidinedioneiThe recommended starting and maintenance dose of nateglinide, alone or in combination with metformin, is 120 mg 3 times/day before meals. 

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. 

If patients have not satisfactorily responded to 1 to 3 months of concomitant therapy with the maximum doses of metformin and an oral sulfonylurea, consider institution of insulin therapy and discontinuation of these oral agents. 

Concomitant metformin IR or ER and insulin therapy in ac/w/fs.Continue the current insulin dose upon initiation of metformin IR or ER therapy. Initiate metformin IR or ER therapy at 500 mg once/day in patients on insulin therapy. For patients not responding adequately, increase the dose of metformin IR or ER by 500 mg after approximately 1 week and by 500 mg every week thereafter until adequate glycemic control is achieved. The maximum recommended daily dose is 2,500 mg for metformin IR and 2,000 mg for metformin ER (2,500 mg with Fortamef). It is recommended that the insulin dose be decreased 10% to 25% when FPG concentrations decrease to less than 120 mg/dL in patients receiving concomitant insulin and metformin IR or ER. Individualize further adjustment based on glucose-lowering response. 

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. 

The extent of metformin absorption from metformin ER at 2,000 mg once-daily dose is similar to the same total daily dose administered as metformin IR 1,000 mg twice daily. 

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). 

Chiidren Safety and efficacy of metformin IR for the treatment of type 2 diabetes have been established in children 10 to 16 years of age who demonstrated a similar response in glycemic control to that seen in adults. Adverse effects were similar to those described in adults. A maximum daily dose of 2,000 mg is recommended. Safety and efficacy of metformin ER in children have not been established. 

Combination therapy - When rosiglitazone is added to existing therapy, the current dose of sulfonylurea, insulin, or metformin can be continued upon initiation of rosiglitazone therapy. 

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