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Impaired hepatic function. Impaired hepatic function has been associated with some cases of lactic acidosis. In general, sitagliptin/metformin should be avoided in patients with evidence of hepatic disease.

Assessment of renal function. Generic Metformin and sitagliptin are substantially excreted by the kidney. The risk of met formin accumulation and lactic acidosis increases with the degree of impairment of renal function. Thus, patients with serum creatinine levels above the ULN for their age should not receive sitagliptin/metformin. In the elderly, careful titration is needed to establish the minimum dose for adequate glycemic effect, because aging can be associated with reduced renal function.

Before therapy is initiated and at least annually thereafter, renal function should be assessed and verified as normal. If renal dysfunction is anticipated, particularly in elderly patients, renal function should be assessed more frequently and the tablets should be discontinued if renal impairment is evident.

Vitamin B₁₂ Levels. In controlled clinical trials of metformin of 29 weeks’ duration, 7% of patients experienced a decrease to subnormal levels of previously normal serum vitamin B₁₂ levels without clinical manifestations. Such a decrease, possibly caused by interference with vitamin B₁₂ absorption from the B₁₂ intrinsic factor complex, however, is rarely associated with anemia, and it appears to be rapidly reversible when metformin medication is discontinued or if vitamin B₁₂ supplementation is provided.

Annual measurements of hematological parameters are advised in patients taking sitagliptin/metformin. Any apparent abnormalities should be appropriately investigated and managed. Patients with inadequate vitamin B₁₂ or calcium intake or absorption tend to experience subnormal vitamin B₁₂ levels. Routine serum vitamin B₁₂ measurements at two- to three-year intervals may be useful for these patients.

Alcohol intake. Because alcohol potentiates the effect of metformin on lactate metabolism, patients should be warned against excessive alcohol intake while taking sitagliptin/met-formin HCl tablets.

Surgical procedures. Sitagliptin/metformin HCl therapy should be temporarily suspended before surgery except for minor procedures that are not associated with restricted intake of food and fluids. The tablets should not be restarted until the patient’s oral intake has resumed and renal function is judged to be normal.

Change in clinical status of patients with previously controlled type-2 diabetes. If patients whose type-2 diabetes has been well controlled with sitagliptin/metformin HCl therapy exhibit laboratory abnormalities or clinical illness (especially vague and poorly defined illness), they should be evaluated promptly for evidence of ketoacidosis or lactic acidosis. Serum electrolytes and ketones, blood glucose and, if indicated, blood pH, lactate, pyruvate, and metformin levels should be determined. If either ketoacidosis or lactic acidosis occurs, the tablets must be stopped immediately and other corrective measures initiated.

Use of Janumet with medications known to cause hypoglycemia:

Sitagliptin. In clinical trials of sitagliptin as monotherapy and with sitagliptin as part of combination therapy with drug metformin or pioglitazone (Generic Actos, Takeda/Lilly), rates of hypoglycemia reported with sitagliptin were similar to rates in patients taking placebo. The use of sitagliptin in combination with medications known to cause hypoglycemia, such as the sulfonylureas or insulin, has not been adequately studied.