Alogliptin inhibits dipeptidyl peptidase 4 (DPP-4), which normally degrades the incretins glucose-dependent insulinotropic polypeptide (GIP) and glucagon like peptide 1 ( GLP-1). The inhibition of DPP-4 increases the amount of active plasma incretins which helps with glycemic control. GIP and GLP-1 stimulate glucose dependent secretion of insulin in pancreatic beta cells. GLP-1 has the additional effects of suppressing glucose dependent glucagon secretion, inducing satiety, reducing food intake, and reducing gastric emptying.
Peak inhibition of DPP-4 occurs within 2-3 hours after a single-dose administration to healthy subjects. The peak inhibition of DPP-4 exceeded 93% across doses of 12.5 mg to 800 mg. Inhibition of DPP-4 remained above 80% at 24 hours for doses greater than or equal to 25 mg. Alogliptin also demonstrated decreases in postprandial glucagon while increasing postprandial active GLP-1 levels compared to placebo over an 8-hour period following a standardized meal. Alogliptin does not affect the QTc interval.
Alogliptin does not undergo extensive metabolism. Two minor metabolites that were detected are N-demethylated alogliptin (<1% of parent compound) and N-acetylated alogliptin (<6% of parent compound). The N-demethylated metabolite is active and an inhibitor of DPP-4. The N-acetylated metabolite is inactive. Cytochrome enzymes that are involved with the metabolism of alogliptin are CYP2D6 and CYP3A4 but the extent to which this occurs is minimal. Approximately 10-20% of the dose is hepatically metabolized by cytochrome enzymes.
Common adverse reactions (reported in ≥4% of patients treated with alogliptin 25 mg and more frequently than in patients who received placebo) are: nasopharyngitis, headache, and upper respiratory tract infection.