Metformin and sitagliptin

Take the missed dose as soon as you remember (be sure to take the medicine with food). Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Dose should be individualized based on patient's current regimen, effectiveness, and tolerability.
Maximum dose: Metformin 2000 mg-sitagliptin 100 mg orally daily

Metformin-sitagliptin immediate release:
-Patients not currently treated with metformin: Metformin 500 mg-sitagliptin 50 mg orally twice a day

-Patients already treated with metformin: Sitagliptin 50 mg and the dose of metformin previously prescribed (500 mg or 1000 mg) orally twice a day. Metformin 1000 mg-sitagliptin 50 mg orally twice a day is recommended for patients already taking metformin 850 mg orally twice a day.

Metformin-sitagliptin extended release:
-Patients not currently treated with metformin: Metformin 1000 mg-sitagliptin 100 mg orally once a day

-Patients already treated with metformin: Sitagliptin 100 mg and the dose of metformin previously prescribed (500 mg or 1000 mg) once a day. For patients taking metformin immediate-release 850 mg or 1000 mg twice a day, the recommended dose is two tablets of sitagliptin metformin 1000 mg-50 mg sitagliptin taken together once a day.

Patients changing between immediate-release and extended-release: Maintain the same daily dose of metformin-sitagliptin

Comments: Co-administration of metformin-sitagliptin with an insulin secretagogue (e.g., sulfonylurea) or insulin may require lower doses of insulin secretagogue or insulin to reduce the risk of hypoglycemia.

Renal impairment: Contraindicated (e.g. serum creatinine levels 1.5 mg/dL or greater in men; 1.4 mg/dL or greater in women, or abnormal CrCl)

New Metformin Renal Dosing: Obtain eGFR prior to initiating therapy:Metformin: Obtain eGFR prior to initiating therapy:
-eGFR less than 30 mL/min/1.73 m2: Use is contraindicated
-eGFR 30 to 45 mL/min/1.73 m2: Initiating therapy is not recommended
-eGFR that falls below 30 mL/min/1.73 m2 during therapy: Discontinue therapy
-eGFR that falls below 45 mL/min/1.73 m2 during therapy: Assess risks versus benefit of continued therapy
-eGFR greater than 45 mL/min/1.73 m2: No dose adjustments recommended

Sitagliptin:
Mild renal impairment (CrCl 50 mL/min or more): No adjustment recommended
Moderate renal impairment (CrCl 30 to less than 50 mL/min): 50 mg orally once a day

IODINATED CONTRAST PROCEDURE:
-For patients with eGFR between 30 and 60 mL/min/1.73 m2: Stop this drug at the time of, or before imaging procedure; re-evaluate eGFR 48 hours after procedure; restart therapy only if renal function is stable.

US BOXED WARNING: Lactic acidosis can occur due to metformin accumulation. The risk increases with conditions such as sepsis, dehydration, excess alcohol intake, hepatic insufficiency, renal impairment, and acute congestive heart failure. Symptoms include malaise, myalgias, respiratory distress, increasing somnolence, and nonspecific abdominal distress. Laboratory abnormalities include low pH, increased anion gap and elevated blood lactate. If acidosis is suspected, discontinue metformin-sitagliptin and hospitalize the patient immediately.

Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.

Administration advice:

-Take orally twice a day with meals (immediate-release metformin) OR once a day with the evening meal (extended-release (XR) metformin)
-Swallow whole, do not crush, cut, or chew
-If a dose is missed, take with food as soon as remembered, but if it is time for the next dose, skip the missed dose; do not take 2 doses as the same time.
-Occasionally, a mass resembling the original tablet (XR) may be eliminated in the feces.

General:
-Temporarily stop treatment prior to radiologic studies utilizing iodinated contrast materials and for surgical procedures when restricted food or fluid intake is expected; may resume once adequate renal function is confirmed.
-This drug is not recommended for patients with type 1 diabetes mellitus or for the treatment of diabetic ketoacidosis as it would not be effective in these settings.

Monitoring:
-Monitor glycemic control
-Renal: Assess renal function baseline and annually; in patients with serum creatinine levels at the upper limit of normal, elderly patients, and in patients at risk for developing renal impairment, more frequent monitoring is recommended.
-Hematologic: Measure hematologic parameters annually
-Monitor for signs and symptoms of pancreatitis
-Monitor for skin disorders such as blistering or ulceration

Patient advice:
-Instruct patient to report signs and symptoms of pancreatitis; if persistent, severe abdominal pain occurs, seek medical advice promptly.
-Hypoglycemia may occur, more commonly when used in combination with insulin or a sulfonylurea.
-Patients should understand the importance of adhering to dietary instructions and regular physical activity; during periods of stress such as fever, trauma, infection, or surgery, management of diabetes may change and patients should be advised to seek medical advice.
-Inform patients about the risk of lactic acidosis, conditions that might predispose them to its occurrence, and symptoms to watch for and report.
-Advise patient that this drug will need to be temporarily stopped if undergoing radiologic studies with intravascular iodinated contrast materials or surgical procedures that will limit food or fluid intake.
-Advise patients on the risks of excessive alcohol intake.
-Instruct patients to contact their health care provider if they develop severe and persistent joint pain.