Metformin interactions

T Pancreatic insulin release Metformin Peripheral insulin sensitivity hepatic glucose output/production i intestinal glucose absorption Dose Ist-line (naive pts), 1.25/250 mg PO daily-bid 2nd-line, 2.5/500 mg or 5/500 mg bid (max 20/2000 mg) take w/ meals, slowly T dose hold before 48 h after ionic contrast media Caution [C, -] Contra SCr >1.4 mg/dL in females or >1.5 mg/dL in males hypoxemic conditions (sepsis, recent MI) alcoholism metabolic acidosis liver Dz Disp Tabs SE HA, hypoglycemia, lactic acidosis, anorexia, N/V, rash Additional Interactions T Effects W/ amiloride, ciprofloxacin cimetidine, digoxin, miconazole, morphine, nifedipine, procainamide, quinidine, quinine, ranitidine, triamterene,... 

Drug interactions can precipitate metformin-induced lactic acidosis, as has been reported after the addition of indometacin (144). 

A possible interaction of orlistat with metformin has been reported. 

Jayasagar G, Krishna Kumar M, Chandrasekhar K, Madhusudan Rao C, Madhusudan Rao Y. Effect of cephalexin on the pharmacokinetics of metformin in healthy human volunteers. Drag Metabol Drag Interact 2002 19(l) 41-8. 

TOPIRAMATE ANTIDIABETIC DRUGS-METFORMIN T metformin levels Unknown mechanism Watch for and warn patients about hypoglycaemia - For signs and symptoms of hypoglycaemia, see Clinical Features of Some Adverse Drug Interactions, Hypoglycaemia... 

METFORMIN H2 RECEPTOR BLOCKERS -CIMETIDINE, RANITIDINE 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 nonspecific 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 the excretory pathway A theoretical possibility. Need to consider l dose of metformin or avoidance of co-administration. Warn patients about hypoglycaemia - For signs and symptoms of hypoglycaemia, see Clinical Features of Some Adverse Drug Interactions, Hypoglycaemia... 

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