REMEVIA-100

Indications

• Type 2 diabetes mellitus as monotherapy (if metformin is inappropriate)
• Type 2 diabetes mellitus in combination with other antidiabetic drugs (including insulin) when metformin alone or in combination fails to achieve adequate glycemic control

Dosage

Adults: 100 mg once daily, or 50 mg twice daily when used in combination with a sulfonylurea or insulin. Dose adjustments may be required based on renal function.

Mechanism of action

Sitagliptin inhibits the enzyme dipeptidyl peptidase-4 (DPP-4), which is responsible for the degradation of incretin hormones. This inhibition results in prolonged active incretin levels, which enhances insulin secretion from pancreatic beta cells and decreases glucagon secretion from alpha cells in the pancreas, leading to lowered blood glucose levels.

Pharmacodynamics

Sitagliptin's pharmacodynamic effects include improved glycemic control, characterized by reduced fasting and postprandial blood glucose levels. The drug is effective in lowering HbA1c levels and is associated with a low risk of hypoglycemia. It has a beneficial effect on weight management, as it typically does not promote weight gain.

Pharmacokinetics

Sitagliptin is absorbed rapidly after oral administration, with peak plasma concentrations occurring within 1-4 hours. Its bioavailability is approximately 87%. The drug is predominantly eliminated via renal excretion, with about 80% of the dose excreted unchanged in the urine. The elimination half-life is approximately 12.4 hours. Renal impairment may necessitate dose adjustments, as clearance is significantly reduced in patients with decreased renal function.

Contra-indications

• History of pancreatitis
• Severe heart failure

Adverse effects

• Headache
• Constipation
• Dizziness
• Skin reactions
• Angioedema
• Back pain
• Cutaneous vasculitis
• Joint disorders
• Myalgia
• Acute pancreatitis
• Acute renal impairment
• Stevens-Johnson syndrome
• Vomiting

Interactions

• Concomitant use with sulfonylureas or insulin may require dose adjustments
• Moderate interaction with vemurafenib (increases exposure)

Precautions

• Monitor renal function before treatment and periodically thereafter
• Discontinue if symptoms of acute pancreatitis occur, such as persistent severe abdominal pain

Pregnancy

Avoid-toxicity observed in animal studies.

Breast-feeding

Avoid-present in milk in animal studies.

Storage

Store at room temperature, away from moisture and heat.

Formulations

• Tablets: 50 mg, 100 mg

Mechanism of action

Inhibition of DPP-4 by sitagliptin slows DPP-4 mediated inactivation of incretins like GLP-1 and GIP. Incretins are released throughout the day and upregulated in response to meals as part of glucose homeostasis. Reduced inhibition of incretins increase insulin synthesis and decrease glucagon release in a manner dependant on glucose concentrations. These effects lead to an overall increase in blood glucose control which is demonstrated by reduced glycosylated hemoglobin (HbA1c). Januvia is a member of a class of oral anti-hyperglycemic agents called dipeptidyl peptidase 4 (DPP-4) inhibitors. The improvement in glycemic control observed with this medicinal product may be mediated by enhancing the levels of active incretin hormones. Incretin hormones, including glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), are released by the intestine throughout the day, and levels are increased in response to a meal. The incretins are part of an endogenous system involved in the physiologic regulation of glucose homeostasis. When blood glucose concentrations are normal or elevated, GLP-1 and GIP increase insulin synthesis and release from pancreatic beta cells by intracellular signaling pathways involving cyclic AMP. Treatment with GLP-1 or with DPP-4 inhibitors in animal models of type 2 diabetes has been demonstrated to improve beta cell responsiveness to glucose and stimulate insulin biosynthesis and release. With higher insulin levels, tissue glucose uptake is enhanced. In addition, GLP-1 lowers glucagon secretion from pancreatic alpha cells. Decreased glucagon concentrations, along with higher insulin levels, lead to reduced hepatic glucose production, resulting in a decrease in blood glucose levels. The effects of GLP-1 and GIP are glucose-dependent such that when blood glucose concentrations are low, stimulation of insulin release and suppression of glucagon secretion by GLP-1 are not observed. For both GLP-1 and GIP, stimulation of insulin release is enhanced as glucose rises above normal concentrations. Further, GLP-1 does not impair the normal glucagon response to hypoglycemia. The activity of GLP-1 and GIP is limited by the DPP-4 enzyme, which rapidly hydrolyzes the incretin hormones to produce inactive products. Sitagliptin prevents the hydrolysis of incretin hormones by DPP-4, thereby increasing plasma concentrations of the active forms of GLP-1 and GIP. By enhancing active incretin levels, sitagliptin increases insulin release and decreases glucagon levels in a glucose-dependent manner. In patients with type 2 diabetes with hyperglycemia, these changes in insulin and glucagon levels lead to lower hemoglobin A1c (HbA1c) and lower fasting and postprandial glucose concentrations. The glucose-dependent mechanism of sitagliptin is distinct from the mechanism of sulfonylureas, which increase insulin secretion even when glucose levels are low and can lead to hypoglycemia in patients with type 2 diabetes and in normal subjects. Sitagliptin is a potent and highly selective inhibitor of the enzyme DPP-4 and does not inhibit the closely-related enzymes DPP-8 or DPP-9 at therapeutic concentrations. Sitagliptin is a DPP-4 inhibitor, which is believed to exert its actions in patients with type 2 diabetes by slowing the inactivation of incretin hormones. Concentrations of the active intact hormones are increased by Januvia, thereby increasing and prolonging the action of these hormones. Incretin hormones, including glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), are released by the intestine throughout the day, and levels are increased in response to a meal. These hormones are rapidly inactivated by the enzyme, DPP-4. The incretins are part of an endogenous system involved in the physiologic regulation of glucose homeostasis. When blood glucose concentrations are normal or elevated, GLP-1 and GIP increase insulin synthesis and release from pancreatic beta cells by

Pharmacodynamics

Sitagliptin inhibits DPP-4 which leads to increased levels of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide(GIP), decreased levels of glucagon, and a stronger insulin response to glucose.