Single doses of up to 800 mg sitagliptin were generally well tolerated. There is no experience with doses above 800 mg in clinical studies.
A large overdose of metformin (or co-existing risks of lactic acidosis) may lead to lactic acidosis which is a medical emergency and must be treated in hospital. The most effective method to remove lactate and metformin is haemodialysis.
In the event of an overdose, it is reasonable to employ the usual supportive measures, e.g., remove unabsorbed material from the gastro-intestinal tract, employ clinical monitoring (including obtaining an electrocardiogram), and institute supportive therapy if required.