Pharmacokinetic drug interaction studies with Steglujan have not been performed; however, such studies have been conducted with ertugliflozin and sitagliptin, the individual active substances of Steglujan.
Ertugliflozin: Pharmacodynamic interactions: Diuretics: Ertugliflozin may add to the diuretic effect of diuretics and may increase the risk of dehydration and hypotension (see Precautions).
Insulin and insulin secretagogues: Insulin and insulin secretagogues, such as sulphonylureas, cause hypoglycaemia. Ertugliflozin may increase the risk of hypoglycaemia when used in combination with insulin and/or an insulin secretagogue. Therefore, a lower dose of insulin or an insulin secretagogue may be required to reduce the risk of hypoglycaemia when used in combination with Steglujan (see Dosage & Administration, Precautions, and Adverse Reactions).
Pharmacokinetic interactions: Effects of other medicinal products on the pharmacokinetics of ertugliflozin: Metabolism by UGT1A9 and UGT2B7 is the primary clearance mechanism for ertugliflozin.
Interaction studies conducted in healthy subjects, using a single dose design, suggest that the pharmacokinetics of ertugliflozin are not altered by sitagliptin, metformin, glimepiride, or simvastatin.
Multiple-dose administration of rifampin (a UGT and CYP inducer) decreases ertugliflozin AUC and Cmax by 39% and 15%, respectively. This decrease in exposure is not considered clinically relevant and therefore, no dose adjustment is recommended. A clinically relevant effect with other inducers (e.g., carbamazepine, phenytoin, phenobarbital) is not expected.
The impact of UGT inhibitors on the pharmacokinetics of ertugliflozin has not been studied clinically, but potential increase in ertugliflozin exposure due to UGT inhibition is not considered to be clinically relevant.
Effects of ertugliflozin on the pharmacokinetics of other medicinal products: Interaction studies conducted in healthy volunteers suggest that ertugliflozin had no clinically relevant effect on the pharmacokinetics of sitagliptin, metformin, and glimepiride.
Coadministration of simvastatin with ertugliflozin resulted in a 24% and 19% increase in AUC and Cmax of simvastatin, respectively, and 30% and 16% increase in AUC and Cmax of simvastatin acid, respectively. The mechanism for the small increases in simvastatin and simvastatin acid is unknown and is not perpetrated through OATP inhibition by ertugliflozin. These increases are not considered to be clinically meaningful.
Sitagliptin: Pharmacokinetic interactions: Effects of other medicinal products on sitagliptin: Sitagliptin is primarily eliminated unchanged in urine, and metabolism is a minor pathway. In vitro studies indicate that the primary enzyme responsible for the limited metabolism of sitagliptin is CYP3A4, with contribution from CYP2C8.
Metabolism may play a more significant role in the elimination of sitagliptin in the setting of severe renal impairment or end-stage renal disease (ESRD). For this reason, it is possible that potent CYP3A4 inhibitors (i.e., ketoconazole, itraconazole, ritonavir, clarithromycin) could alter the pharmacokinetics of sitagliptin in patients with severe renal impairment or ESRD.
Interaction studies conducted in patients with type 2 diabetes or healthy volunteers suggest that metformin and ciclosporin had no clinically relevant effect on the pharmacokinetics of sitagliptin.
Effects of sitagliptin on other medicinal products: In drug interaction studies, sitagliptin did not have clinically meaningful effects on the pharmacokinetics of the following: metformin, rosiglitazone, glyburide, simvastatin, warfarin, and oral contraceptives.
Digoxin: Sitagliptin had a small effect on plasma digoxin concentrations. Following administration of 0.25 mg digoxin concomitantly with 100 mg of sitagliptin daily for 10 days, the plasma AUC of digoxin was increased on average by 11% and the plasma Cmax on average by 18%. No dose adjustment of digoxin is recommended. However, patients at risk of digoxin toxicity should be monitored for this when sitagliptin and digoxin are administered concomitantly.