LINAGLIPTIN AND METFORMIN HYDROCHLORIDE
Clinical safety rating: safe
Alcohol and contrast dye can increase risk of lactic acidosis Can cause lactic acidosis a rare but serious metabolic complication.
Linagliptin inhibits dipeptidyl peptidase-4 (DPP-4), increasing incretin levels (GLP-1, GIP) to enhance insulin secretion and suppress glucagon. Metformin reduces hepatic glucose production, decreases intestinal glucose absorption, and improves insulin sensitivity.
| Metabolism | Linagliptin: minimal metabolism, primarily excreted unchanged in feces via enterohepatic system (small contributions from CYP3A4). Metformin: not metabolized; excreted unchanged in urine. |
| Excretion | Linagliptin: ~85% fecal (biliary), ~5% renal; Metformin: 90-100% renal (unchanged). |
| Half-life | Linagliptin: 12-14 hours (terminal); Metformin: 6.2 hours (terminal). |
| Protein binding | Linagliptin: 70-80% (concentration-dependent, primarily to albumin); Metformin: negligible (0-5%). |
| Volume of Distribution | Linagliptin: 10-20 L (Vd); Metformin: 1-5 L/kg (Vd). |
| Bioavailability | Linagliptin: ~30% (oral); Metformin: 50-60% (oral, under fasting conditions). |
| Onset of Action | Linagliptin: 1-2 hours (oral, inhibition of DPP-4); Metformin: 2-3 hours (oral, reduction of hepatic glucose production). |
| Duration of Action | Linagliptin: >24 hours (once-daily dosing); Metformin: 12-24 hours (twice-daily dosing). |
Typical adult dose: one tablet containing linagliptin 2.5 mg and metformin hydrochloride 1000 mg orally twice daily with meals. Maximum daily dose: linagliptin 5 mg, metformin 2000 mg.
| Dosage form | TABLET |
| Renal impairment | Contraindicated if eGFR < 30 mL/min/1.73 m². For eGFR 30-45: reduce metformin component to 500 mg twice daily; avoid initiating therapy. If eGFR falls below 30, discontinue. For eGFR 45-60: use caution; consider reducing metformin dose in patients at risk for lactic acidosis. |
| Liver impairment | Avoid use in patients with Child-Pugh class B or C hepatic impairment due to metformin-associated lactic acidosis risk. No specific dose adjustment is required for linagliptin in mild hepatic impairment; use caution if severe hepatic impairment. |
| Pediatric use | Safety and efficacy in pediatric patients (<18 years) have not been established. Not recommended due to lack of data. |
| Geriatric use | Start with lower doses of metformin (e.g., 500 mg twice daily) in elderly patients, especially those >80 years, due to increased risk of lactic acidosis. Monitor renal function regularly; avoid if eGFR < 30 mL/min/1.73 m². No specific dose adjustment for linagliptin based on age alone, but use caution with declining renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Alcohol and contrast dye can increase risk of lactic acidosis Can cause lactic acidosis a rare but serious metabolic complication.
| FDA category | Human |
| Breastfeeding | Linagliptin: Unknown if excreted in human milk; low molecular weight suggests potential for excretion. Metformin: Excreted in breast milk in small amounts; M/P ratio approximately 0.35-0.5. Infant exposure is estimated at 1-4% of maternal weight-adjusted dose. No adverse effects reported in breastfed infants. Considered compatible with breastfeeding, but monitor infant for hypoglycemia. |
| Teratogenic Risk |
■ FDA Black Box Warning
No black box warning for this combination; however, metformin has warnings for lactic acidosis (not a boxed warning in the US, but a boxed warning in some countries).
| Common Effects | Diarrhea |
| Serious Effects |
["Renal impairment (eGFR < 30 mL/min/1.73 m²)","Acute or chronic metabolic acidosis (including diabetic ketoacidosis)","Severe infection, dehydration, or hypoperfusion","History of hypersensitivity to linagliptin or metformin"]
| Precautions | ["Lactic acidosis risk (renal impairment, hypoxia, sepsis, alcohol use, hepatic impairment); discontinue if suspected","Pancreatitis (monitor for symptoms); hypersensitivity reactions; acute kidney injury; vitamin B12 deficiency with prolonged metformin use; hypoglycemia when used with insulin or sulfonylureas"] |
Loading safety data…
| Linagliptin: Limited human data; animal studies show no teratogenicity at clinically relevant doses. Metformin: Generally considered low risk; some studies suggest possible association with preeclampsia and neonatal hypoglycemia, but not consistent malformations. In first trimester, metformin appears safe; second and third trimester risk may include increased abortion risk and potential fetal hypoglycemia. Overall, FDA category B for linagliptin and category B for metformin. |
| Fetal Monitoring | Monitor maternal renal function (serum creatinine, eGFR) at baseline and periodically due to metformin clearance. Assess glycemic control with HbA1c and blood glucose levels. During pregnancy, increased risk of lactic acidosis with metformin; monitor for symptoms (nausea, abdominal pain, hyperventilation). Fetal surveillance: growth scans for macrosomia or large-for-gestational-age, especially in diabetic pregnancies; consider serial ultrasounds. Monitor for hypoglycemia in neonate after delivery. |
| Fertility Effects | Linagliptin: No known direct effects on fertility; animal studies show no impairment. Metformin: May improve fertility in women with polycystic ovary syndrome (PCOS) by lowering insulin resistance and inducing ovulation. No negative impact on male fertility; some studies suggest improvement in PCOS-related infertility. Use during pregnancy planning may be beneficial in PCOS. |