Sitagliptin: During controlled clinical trials in healthy subjects, single doses of up to sitagliptin 800 mg were administered. Maximal mean increases in QTc of 8 msec were observed in 1 study at a dose of sitagliptin 800 mg, a mean effect that is not considered clinically important (see Pharmacology under Actions). There is no experience with doses >800 mg in clinical studies. In phase I multiple-dose studies, there were no dose-related clinical adverse reactions observed with sitagliptin with doses of up to 400 mg/day for periods of up to 28 days.
In the event of an overdose, it is reasonable to employ the usual supportive measures eg, remove unabsorbed material from the gastrointestinal tract, employ clinical monitoring (including obtaining an electrocardiogram) and institute supportive therapy as indicated by the patient's clinical status.
Sitagliptin is modestly dialyzable. In clinical studies, approximately 13.5% of the dose was removed over a 3- to 4-hr hemodialysis session. Prolonged hemodialysis may be considered if clinically appropriate. It is not known if sitagliptin is dialyzable by peritoneal dialysis.
Metformin HCl: Overdose of metformin HCl has occurred, including ingestion of amounts >50 g. Hypoglycemia was reported in approximately 10% of cases, but no causal association with metformin HCl has been established. Lactic acidosis has been reported in approximately 32% of metformin overdose cases (see Precautions). Metformin is dialyzable with a clearance of up to 170 mL/min under good hemodynamic conditions. Therefore, hemodialysis may be useful for removal of accumulated drug from patients in whom metformin overdosage is suspected.