Sitavia Drug Interactions

Drugs Metabolized by Hepatic Microsomal Enzymes: Sitagliptin is metabolized to a limited extent by cytochrome P-450 (CYP) isoenzymes 3A4 and 2C8 to inactive metabolites. Sitagliptin does not inhibit CYP isoenzymes 1A2, 2B6, 2C8, 2C9, 2C19, 2D6, or 3A4 in vitro or induce CYP3A4. Pharmacokinetic interactions with drugs metabolized by these isoenzymes are unlikely.
Drug Secreted by Renal Tubular Cationic Transport: Sitagliptin is a substrate of the organic anion transport system; pharmacokinetic interactions are unlikely with substrates of the organic cationic transport system.
Inhibitors of P-glycoprotein Transport System: Sitagliptin is a substrate of the P-glycoprotein transport system. There is a potential pharmacokinetic interaction (increased absorption and renal clearance of sitagliptin) with P-glycoprotein inhibitors.
Protein-bound Drugs: Pharmacokinetic interactions between sitagliptin and protein-bound drugs are unlikely.
Cyclosporine: Concomitant administration of cyclosporine and sitagliptin may increase absorption and plasma concentrations of sitagliptin. However, this interaction is not considered clinically important.
Digoxin: Concomitant administration of sitagliptin (100 mg daily for 10 days) with digoxin resulted in a slight increase in plasma concentrations and area under the concentration-time curve (AUC) of digoxin (18 and 11%, respectively). While these increases are not considered clinically important, patients receiving digoxin should be monitored appropriately; however, no digoxin or sitagliptin dosage adjustment is needed.
Hormonal Contraceptives, Oral: Sitagliptin has no clinically important effect on the pharmacokinetics of norethindrone or ethinyl estradiol.
Metformin: Sitagliptin and metformin have a potential additive effect on active glucagon-like peptide (GLP-1) concentrations. Pharmacokinetic interactions are unlikely.
The relevance of these effects to glycemic control in patients with type 2 diabetes mellitus is unclear.
Simvastatin: Pharmacokinetic interactions between sitagliptin and simvastatin are unlikely.
Sulfonylureas or Insulin: Clinically important pharmacokinetic interactions between sitagliptin and sulfonylureas (e.g. glimepiride, glipizide, glyburide, tolbutamide) are unlikely.
Thiazolidinediones: Pharmacokinetic interactions between sitagliptin and thiazolidinediones are unlikely.
Warfarin: Pharmacokinetic interactions between sitagliptin and warfarin are unlikely.