Sitagliptin is an FDA-approved drug and is marketed under the trade name Januvia for treatment of diabetes mellitus type 2. According to WebMD, type 2 diabetes is the most common and affects up to 95 percent of Americans with diabetes. Unlike type 1 diabetes, type 2 diabetes makes insulin but not enough. Known as insulin resistance, not enough insulin is able to get into the body, and a build-up of glucose in the blood is caused. Over time, this can damage heart, kidney and eye vessels, cause dehydration and even a diabetic coma.
Specifically, sitagliptin inhibits the DPP-4 enzyme and enhances GLP-1 and GIP activation to increase the secretion of insulin. As a result, the blood glucose levels are able to stabilize and reach normal levels. Once the blood glucose levels stabilize, the released insulin subsides. Often, sitagliptin is used in combination with another drug known as metformin. Anyone can get type 2 diabetes, but risk factors include obesity, sedentary lifestyle, genetics and those over 45 years of age.
Clinical Studies of Sitagliptin
Two placebo-controlled monotherapy studies were done with administering Januvia 200 milligrams daily and 100 milligrams daily over an 18-week period and 24-week period. In these clinical trials, adverse reactions occurred in less than 5 percent of patients, and blood glucose levels were stabilized. In other controlled clinical studies, the use of sitagliptin and metformin had a low incidence of adverse reactions, and blood glucose levels were stabilized.
The administration of stitagliptin has been proven to inhibit the DPP-4 enzyme for 24 hours. After eating and taking the medication, this drug has resulted in a three-fold increase level of active GIP and GLP-1, higher C-peptide concentrations and decreased glucagon concentrations. The result of increased insulin is directly related to the oral glucose load and eating.
Pharmacokinetics of Sitagliptin
The pharmacokinetics of sitagliptin is the same in both healthy subjects as in those with type 2 diabetes. The absorption rate is about 87 percent with or without food. Its distribution rate is 198 liters following a single 100 milligram intraveneous dosage. About 79 percent of it is excreted in the urine. The recommended dosage of sitagliptin is 100 milligrams per day. No dosage adjustment is based just on age, and it’s important to note that the pharmacokinetics of sitagliptin has not been studied in pediatric patients with type 2 diabetes. There is also no dosage adjustment required for those with moderate hepatic insufficiency.