Drugs Affecting Glucose Metabolism
A number of medications affect glucose metabolism and may require AMARYL dose adjustment and particularly close monitoring for hypoglycemia or worsening glycemic control.
The following are examples of medications that may increase the glucose-lowering effect of sulfonylureas including AMARYL, increasing the susceptibility to and/or intensity of hypoglycemia: oral anti-diabetic medications, pramlintide acetate, insulin, angiotensin converting enzyme (ACE) inhibitors, H2 receptor antagonists, fibrates, propoxyphene, pentoxifylline, somatostatin analogs, anabolic steroids and androgens, cyclophosphamide, phenyramidol, guanethidine, fluconazole, sulfinpyrazone, tetracyclines, clarithromycin, disopyramide, quinolones, and those drugs that are highly protein-bound, such as fluoxetine, nonsteroidal anti-inflammatory drugs, salicylates, sulfonamides, chloramphenicol, coumarins, probenecid and monoamine oxidase inhibitors. When these medications are administered to a patient receiving AMARYL, monitor the patient closely for hypoglycemia. When these medications are withdrawn from a patient receiving AMARYL, monitor the patient closely for worsening glycemic control.
The following are examples of medications that may reduce the glucose-lowering effect of sulfonylureas including AMARYL, leading to worsening glycemic control: danazol, glucagon, somatropin, protease inhibitors, atypical antipsychotic medications (e.g., olanzapine and clozapine), barbiturates, diazoxide, laxatives, rifampin, thiazides and other diuretics, corticosteroids, phenothiazines, thyroid hormones, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics (e.g., epinephrine, albuterol, terbutaline), and isoniazid. When these medications are administered to a patient receiving AMARYL, monitor the patient closely for worsening glycemic control. When these medications are withdrawn from a patient receiving AMARYL, monitor the patient closely for hypoglycemia.
Beta-blockers, clonidine, and reserpine may lead to either potentiation or weakening of AMARYL's glucose-lowering effect.
Both acute and chronic alcohol intake may potentiate or weaken the glucose-lowering action of AMARYL in an unpredictable fashion.
The signs of hypoglycemia may be reduced or absent in patients taking sympatholytic drugs such as beta-blockers, clonidine, guanethidine, and reserpine.
A potential interaction between oral miconazole and sulfonylureas leading to severe hypoglycemia has been reported. Whether this interaction also occurs with other dosage forms of miconazole is not known.
Cytochrome P450 2C9 Interactions
There may be an interaction between glimepiride and inhibitors (e.g., fluconazole) and inducers (e.g., rifampin) of cytochrome P450 2C9. Fluconazole may inhibit the metabolism of glimepiride, causing increased plasma concentrations of glimepiride which may lead to hypoglycemia. Rifampin may induce the metabolism of glimepiride, causing decreased plasma concentrations of glimepiride which may lead to worsening glycemic control.
Concomitant Administration of Colesevelam
Colesevelam can reduce the maximum plasma concentration and total exposure of glimepiride when the two are coadministered. However, absorption is not reduced when glimepiride is administered 4 hours prior to colesevelam. Therefore, AMARYL should be administered at least 4 hours prior to colesevelam.