Home Drug Guide Sitagliptin and Metformin Hydrochloride

Drug Guide

Generic Name

Sitagliptin and Metformin Hydrochloride

Brand Names Janumet

Classification

Therapeutic: Antidiabetic agent

Pharmacological: Combination of dipeptidyl peptidase-4 inhibitor and biguanide

FDA Approved Indications

Type 2 diabetes mellitus as an adjunct to diet and exercise to improve glycemic control

Mechanism of Action

Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor that increases levels of incretin hormones, enhancing insulin release and decreasing glucagon levels. Metformin decreases hepatic glucose production, increases insulin sensitivity, and enhances peripheral glucose uptake.

Dosage and Administration

Adult: Adults: The typical dose is one tablet twice daily with meals. Dosage adjustment based on renal function.

Pediatric: Not approved for pediatric use.

Geriatric: Adjust dose based on renal function; increased caution in elderly due to renal impairment.

Renal Impairment: Dose adjustment required based on the severity of impairment; contraindicated in severe renal impairment.

Hepatic Impairment: Use with caution; no specific dose adjustment necessary.

Pharmacokinetics

Absorption: Rapidly absorbed, peak plasma concentration in 1-4 hours.

Distribution: Sitagliptin: Widely distributed; Metformin: Low protein binding.

Metabolism: Sitagliptin minimally metabolized; Metformin not metabolized, excreted unchanged.

Excretion: Renal excretion for both components.

Half Life: Sitagliptin: approximately 12 hours; Metformin: approximately 17.6 hours.

Contraindications

Severe renal impairment (eGFR <30 mL/min/1.73 m²)
Metabolic acidosis, including diabetic ketoacidosis

Precautions

History of pancreatitis, liver disease, risk of lactic acidosis, use with caution in elderly and renal impairment, monitor renal function regularly.

Adverse Reactions - Common

Nasopharyngitis (Common)
Headache (Common)
Diarrhea (Common)
Nausea (Common)

Adverse Reactions - Serious

Pancreatitis (Rare)
Lactic acidosis (Very rare)

Drug-Drug Interactions

Cimetidine (may increase sitagliptin levels)
Alcohol (risk of lactic acidosis through synergistic effects)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor blood glucose levels, renal function (serum creatinine, eGFR), and for signs of pancreatitis.

Diagnoses:

Ineffective therapeutic regimen management related to adverse effects or inappropriate medication use.

Implementation: Administer with meals, monitor blood glucose and renal function regularly, educate patient on signs of lactic acidosis and pancreatitis.

Evaluation: Assess glycemic control, renal function, and patient adherence.

Patient/Family Teaching

Take medication with meals to reduce gastrointestinal side effects.
Notify healthcare provider if experiencing severe stomach pain, vomiting, jaundice, or signs of infection.
Maintain a consistent diet and exercise regimen.
Report signs of hypoglycemia, although less common with this medication.

Special Considerations

Black Box Warnings:

Risk of lactic acidosis with metformin, especially in renal impairment.

Genetic Factors: Genetic variations may affect drug metabolism and response.

Lab Test Interference: May increase serum creatinine levels; monitor renal function.

Overdose Management

Signs/Symptoms: Severe hypoglycemia if used with other hypoglycemic agents, lactic acidosis with metformin overdose.

Treatment: Discontinue medication, supportive care, and in case of lactic acidosis, consider hemodialysis.

Storage and Handling

Storage: Store at room temperature, 20-25°C, away from moisture and light.

Stability: Stable under recommended storage conditions.