Symptoms: Sitagliptin Phosphate: During controlled clinical trials in healthy subjects, single doses of up to sitagliptin 800 mg were generally well tolerated. Minimal increases in QTc, not considered to be clinically relevant, were observed in 1 study at a dose of sitagliptin 800 mg (see Pharmacology under Actions). There is no experience with doses above 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 600 mg/day for 10 days and 400 mg/day for periods of up to 28 days.
Metformin hydrochloride: Overdosage of metformin hydrochloride has occurred, including ingestion of amounts >50 g. Hypoglycemia was reported in approximately 10% of cases, but no causal association with metformin hydrochloride has been established. Lactic acidosis has been reported in approximately 32% of metformin overdose cases (see Precautions).
Treatment: Sitagliptin Phosphate: In the event of an overdosage, 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 if required.
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 hydrochloride: 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.