Home Drug Guide Metformin Hydrochloride and Sitagliptin Phosphate

Drug Guide

Generic Name

Metformin Hydrochloride and Sitagliptin Phosphate

Brand Names Jentadueto, Janumet

Classification

Therapeutic: Antidiabetic agent

Pharmacological: Combination of biguanide and DPP-4 inhibitor

FDA Approved Indications

Type 2 diabetes mellitus, to improve glycemic control

Mechanism of Action

Metformin decreases hepatic glucose production and increases insulin sensitivity; Sitagliptin inhibits DPP-4 enzyme, increasing incretin levels, which increase insulin synthesis and release, and decrease glucagon secretion.

Dosage and Administration

Adult: Typically one tablet twice daily with meals, dosage varies based on patient response

Pediatric: Not approved for pediatric use

Geriatric: Start with lower doses considering reduced renal function

Renal Impairment: Adjust dose based on renal function, contraindicated if eGFR below 30 mL/min/1.73 m²

Hepatic Impairment: Use with caution, contraindicated in severe hepatic disease

Pharmacokinetics

Absorption: Well absorbed, peak plasma levels in 1-4 hours

Distribution: Widely distributed, low protein binding

Metabolism: Metformin not metabolized; Sitagliptin minimally metabolized

Excretion: Renal excretion primarily for both drugs

Half Life: Metformin ~17.6 hours, Sitagliptin ~12.4 hours

Contraindications

Renal impairment (eGFR <30 mL/min/1.73 m²)
Severe hepatic impairment
Acute or chronic metabolic acidosis

Precautions

Use with caution in elderly, dehydration, infections, or surgery

Adverse Reactions - Common

Gastrointestinal disturbances (nausea, diarrhea) (Common)
Upper respiratory tract infection (Common)

Adverse Reactions - Serious

Lactic acidosis (Rare but serious)
Pancreatitis (Rare)

Drug-Drug Interactions

Cationic drugs that affect renal function (e.g., diuretics, NSAIDs)

Drug-Food Interactions

N/A

Drug-Herb Interactions

St. John’s Wort (may decrease efficacy)

Nursing Implications

Assessment: Monitor renal function, blood glucose levels, and signs of hypoglycemia or lactic acidosis

Diagnoses:

Risk for hypoglycemia
Risk for lactic acidosis

Implementation: Administer with meals to reduce gastrointestinal side effects

Evaluation: Assess blood sugar control and renal function periodically

Patient/Family Teaching

Take medication with meals to reduce gastrointestinal upset
Inform provider of any signs of lactic acidosis (muscle pain, abnormal fatigue, hyperventilation)
Maintain hydration

Special Considerations

Black Box Warnings:

Lactic acidosis risk

Genetic Factors: None specific

Lab Test Interference: None

Overdose Management

Signs/Symptoms: Severe hypoglycemia or lactic acidosis

Treatment: Supportive care, hemodialysis in severe cases, discontinue medication immediately

Storage and Handling

Storage: Store at room temperature, away from moisture and light

Stability: Stable under recommended storage conditions