Sitagliptin / Metformin Hydrochloride

Trade Names:
Janumet
- Tablets sitagliptin 50 mg/metformin hydrochloride 500 mg
- Tablets sitagliptin 50 mg/metformin hydrochloride 1,000 mg

Pharmacology

User Reviews & Ratings As a treatment for... Avg User Ratings [?] Diabetes, Type 2 12 reviews Rate it! 8.3 Compare with other drugs.

Slows the inactivation of incretin hormones.

Decreases hepatic glucose production, decreases intestinal absorption of glucose, and improves insulin sensitivity by increasing peripheral glucose uptake and utilization.

Indications and Usage

Adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes when treatment with both sitagliptin and metformin is appropriate.

Contraindications

Renal disease or renal function impairment; acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma; hypersensitivity to any component of the product. Temporarily discontinue treatment in patients undergoing radiologic studies involving intravascular administration of iodinated contrast materials; use of such products may alter renal function.

Dosage and Administration

Base dosage selection of sitagliptin/metformin on the patient's current dose of these agents (max, sitagliptin 100 mg/metformin 2,000 mg daily).

PO Start with sitagliptin 50 mg twice daily plus the current dose of metformin. For patients taking metformin 850 mg twice daily, the recommended starting dosage is sitagliptin 50 mg/metformin 1,000 mg twice daily.

PO Start with sitagliptin 50 mg/metformin 500 mg twice daily. Titrate patient up to sitagliptin 50 mg/metformin 1,000 mg twice daily. Patients taking sitagliptin monotherapy whose dose has been adjusted for renal function impairment should not be switched to sitagliptin plus metformin.

PO The usual starting dosage should provide sitagliptin dosed as 50 mg twice daily. In determining the starting dose of metformin, the patient's level of glycemic control and current dose, if any, of metformin should be considered. Gradual dose escalation to reduce the GI adverse reactions associated with metformin should be considered. Patients currently receiving or initiating a sulfonylurea may require lower sulfonylurea doses to reduce the risk of hypoglycemia.

PO Start with sitagliptin 50 mg/metformin 500 mg twice daily. Patients with inadequate glycemic control on this dosage can be titrated up to sitagliptin 50 mg/metformin 1,000 mg twice daily.

PO Initiate therapy with the dose of sitagliptin and metformin already being taken.

General Advice

• In general, administer twice daily with meals.

Storage/Stability

Store at 59° to 86°F.

Drug Interactions

Hypoglycemic effects and the effects of metformin on lactic acidosis may be potentiated.

May compete with metformin for renal tubular transport.

Metformin plasma levels may be increased.

Digoxin AUC and C _max may be slightly increased.

Closely monitor patient to maintain adequate glycemic control.

Metformin AUC and C _max may be increased while the AUC and C _max of furosemide may be decreased.

Glyburide AUC and C _max may be decreased.

Metformin AUC and C _max may be increased.

Risk of metformin-induced lactic acidosis may be increased. Temporarily discontinue metformin at the time of or prior to the procedure and withhold for 48 h subsequent to the procedure; reinstitute only after renal function has been reevaluated and found to be healthy.

May increase hypoglycemia.

Laboratory Test Interactions

None well documented.

Adverse Reactions

The following adverse reactions were reported with sitagliptin/metformin combination therapy.

CNS

Headache (6%).

Dermatologic

Exfoliative conditions (including Stevens-Johnson syndrome), rash, urticaria (postmarketing).

GI

Diarrhea (8%); nausea (5%); abdominal pain (3%); vomiting (2%).

Hypersensitivity

Angioedema, hypersensitivity including anaphylaxis (postmarketing).

Metabolic-Nutritional

Hypoglycemia (2%).

Respiratory

Upper respiratory tract infection (6%).

Precautions

Pregnancy

Category B .

Lactation

Metformin is excreted, but is considered compatible with breast-feeding; undetermined for sitagliptin.

Children

Safety and efficacy not established.

Elderly

Use with caution because of possible age-related reduction in renal function.

Hypersensitivity

There have been postmarketing reports of serious hypersensitivity reactions in patients treated with sitagliptin. Reactions include anaphylaxis, angioedema, and exfoliative skin conditions, including Stevens-Johnson syndrome.

Renal Function

Metformin accumulation and lactic acidosis risk increases with the degree of renal function impairment.

Hepatic Function

Avoid metformin in patients with clinical or laboratory evidence of hepatic disease.

Special Risk Patients

Debilitated, malnourished, or elderly patients, and patients with adrenal or pituitary insufficiency or alcohol intoxication are particularly susceptible to hypoglycemic effects. Hypoglycemia may be difficult to recognize in elderly patients and in people who are taking beta-blocking agents.

Changes in clinical status

Promptly evaluate patients with type 2 diabetes previously well controlled who develop laboratory abnormalities or clinical illness for ketoacidosis or lactic acidosis.

Hypoxic states

Immediately discontinue therapy in any condition characterized by hypoxemia (eg, acute CHF, MI).

Loss of blood glucose control

Patients exposed to stress (eg, fever, infection, surgery, trauma) may experience a loss in glycemic control. It may be necessary to withhold sitagliptin/metformin and temporarily administer insulin until an acute episode has been resolved.

Surgical patients

Temporarily suspend treatment for any surgical procedure, except in procedures not associated with restricted intake of food and fluids, and do not restart treatment until oral intake has resumed and renal function has been evaluated as healthy.

Vitamin B ₁₂ levels

Metformin may decrease vitamin B ₁₂ levels.

Overdosage

Symptoms

Increased QTc interval 8 msec (not considered clinically important).

Hypoglycemia, lactic acidosis.

Patient Information

• Advise patient to read the patient information leaflet before using product the first time and with each refill.
• Advise patient or caregiver to take prescribed dose with meals.
• Counsel patient against excessive alcohol intake, either acute or chronic.
• Educate patient, family, or caregiver about symptoms of lactic acidosis.
• Educate patient, family, or caregiver regarding type 2 diabetes and its management.
• Instruct patient that this drug is not a substitute for diet and exercise, and to follow prescribed regimens.
• Emphasize the importance of regular daily blood glucose monitoring and periodic HbA _1c tests.
• Review symptoms of hypoglycemia and hyperglycemia, and action plans to undertake in the event either occur.
• Instruct patients to report hypoglycemic or hyperglycemic episodes to health care provider.
• Advise patients that during periods of stress (eg, fever, infection, surgery, trauma), medication requirements may change and to seek medical advice promptly.

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