Monograph Details

Endocrine System > Diabetes
FORTAMET
Manufacturer
Sciele Pharma, Inc.
Legal Classification
Rx
Pharmacological Class
Biguanide.
Generic Name
Metformin HCl 500mg, 1000mg; ext-rel tabs.
Indications
Adjunct to diet and exercise in type 2 diabetes as monotherapy, or with a sulfonylurea or insulin.
Children
≤17yrs: not recommended.
Adults
Swallow whole. Take with evening meal. ≥17yrs: Monotherapy: Initially 1000mg once daily; may increase by 500mg/day at 1-week intervals; max 2.5g once daily. Adding to insulin: Initially 500mg once daily; may increase by 500mg/day at 1-week intervals; max 2.5g/day. Reduce insulin dose by 10–25% as needed. Concomitant sulfonylureas: see literature.
Contraindications
Renal disease or dysfunction. Metabolic acidosis, ketoacidosis. Concomitant intravascular iodinated contrast agents (suspend during and for 48 hours after use).
Precautions
Confirm normal renal function before starting and monitor (esp. in patients ≥80 years). Avoid if clinical or lab evidence of hepatic disease. Discontinue if lactic acidosis, ketoacidosis, renal impairment, shock, acute MI, sepsis, acute CHF, or hypoxemia occurs. Suspend therapy if dehydration occurs or before surgery. Monitor hematology (esp. serum Vit. B12 in susceptible patients). Secondary failure. Elderly, debilitated, uncompensated strenuous exercise, stress, malnourished or deficient caloric intake, adrenal or pituitary insufficiency, or alcohol intoxication: increased risk of hypoglycemia. Pregnancy (Cat.B), nursing mothers: not recommended; consider using insulin instead.
Interactions
Cationic drugs eliminated by renal tubular secretion (eg, amiloride, digoxin, morphine, procainamide, quinidine, quinine, ranitidine, triamterene, trimethoprim, vancomycin), furosemide, nifedipine: may increase metformin levels. Avoid excessive alcohol intake (potentiates effects of metformin on lactate). Diuretics, steroids, phenothiazines, phenytoin, niacin, sympathomimetics, calcium channel blockers, isoniazid, others that may cause hyperglycemia. Increased risk of hypoglycemia with alcohol, sulfonylureas, insulin. β-blockers may mask hypoglycemia.
Adverse Reactions
GI disturbances, lactic acidosis (rare, half of the cases are fatal).
How Supplied
Tabs—60
Additional Resources
Related Prescribing Note