ACTOPLUS MET
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ACTOPLUS MET (ACTOPLUS MET).
Actoplus Met combines pioglitazone, a thiazolidinedione that improves insulin sensitivity by activating peroxisome proliferator-activated receptor gamma (PPARγ), and metformin, a biguanide that decreases hepatic glucose production and improves peripheral glucose uptake.
| Metabolism | Pioglitazone: extensively metabolized via CYP2C8 and CYP3A4; metformin: excreted unchanged in urine, not metabolized by CYP450 enzymes. |
| Excretion | Pioglitazone: predominantly hepatic metabolism and biliary excretion of metabolites, with 15–30% recovered in urine (mostly metabolites) and the remainder in feces. Metformin: 90% excreted unchanged in urine via glomerular filtration and tubular secretion, with <10% in feces. |
| Half-life | Pioglitazone: terminal half-life 3–7 hours (parent drug) for elimination, with active metabolites prolonging clinical effects up to 24 hours. Metformin: 6.2 hours (plasma), prolonged to 17.6 hours in renal impairment (e.g., CrCl <60 mL/min). |
| Protein binding | Pioglitazone: >99% bound to albumin. Metformin: negligible (<5%) binding to plasma proteins. |
| Volume of Distribution | Pioglitazone: 0.25 L/kg; indicates distribution into tissues. Metformin: 1–5 L/kg; large Vd suggests extensive tissue distribution (e.g., GI tract, liver, kidney). |
| Bioavailability | Pioglitazone: 83% (oral); food slightly delays absorption. Metformin: 50–60% (immediate-release) with saturable absorption; extended-release: lower bioavailability (~40%) due to formulation. Both components are orally administered. |
| Onset of Action | Pioglitazone: 2–4 weeks for full glycemic effect; single dose: gradual onset over hours. Metformin: Immediate-release: 1–2 hours; Extended-release: 4–8 hours. |
| Duration of Action | Pioglitazone: 24 hours (dosing once daily). Metformin: Immediate-release: 6–8 hours; Extended-release: 24 hours. |
ACTOPLUS MET (pioglitazone/metformin) is available as tablets of 15 mg/500 mg, 15 mg/850 mg, and 15 mg/1000 mg. The usual starting dose is 15 mg/500 mg twice daily or 15 mg/850 mg once daily, gradually titrated based on glycemic response and tolerability. Maximum recommended dose is 45 mg pioglitazone and 2000 mg metformin per day.
| Dosage form | TABLET |
| Renal impairment | Contraindicated if eGFR < 30 mL/min/1.73 m². For eGFR 30-44 mL/min/1.73 m², reduce metformin dose by 50%, do not exceed pioglitazone 15 mg/day. For eGFR 45-59 mL/min/1.73 m², decrease metformin dose by 50% (max 1000 mg/day) and reassess renal function every 3 months. Pioglitazone may be used with caution but dose reduction is not specifically required; however, edema risk increases. |
| Liver impairment | Contraindicated in Child-Pugh class C. For Child-Pugh class A or B, avoid metformin if liver enzymes > 3 times upper limit of normal (ULN) or if active liver disease. Pioglitazone should not be used in patients with active liver disease or ALT > 2.5 times ULN. No specific dose adjustment guidelines exist for Child-Pugh; however, due to risk of hepatotoxicity, alternative agents are recommended in any hepatic impairment. |
| Pediatric use | Safety and efficacy in pediatric patients (<18 years) have not been established. Not recommended for use. |
| Geriatric use |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ACTOPLUS MET (ACTOPLUS MET).
| Breastfeeding | Metformin is excreted into breast milk in small amounts (M/P ratio approximately 0.35). Pioglitazone is detected in rat milk; human data unavailable. Caution due to potential for neonatal hypoglycemia and unknown effects. Not recommended while breastfeeding. |
| Teratogenic Risk | Pregnancy Category N (not assigned by FDA; ACTOPLUS MET contains pioglitazone and metformin. Pioglitazone is Pregnancy Category C, metformin is Pregnancy Category B. Limited human data; pioglitazone caused delayed parturition and embryotoxicity in animals at high doses. Use only if clearly needed; insulin preferred for glycemic control in pregnancy. |
■ FDA Black Box Warning
Pioglitazone may cause or exacerbate congestive heart failure. Monitor patients closely. Not recommended in patients with symptomatic heart failure. Lactic acidosis: Rare but serious metformin-associated adverse event; risk increases with renal impairment, hepatic disease, acute illness, alcohol intake, or hypoxic states.
| Serious Effects |
Severe renal impairment (eGFR <30 mL/min/1.73 m²); acute or chronic metabolic acidosis, including diabetic ketoacidosis; history of lactic acidosis; hypersensitivity to pioglitazone, metformin, or any component; symptomatic heart failure; hepatic impairment (elevated transaminases >2.5x ULN); acute illness that may predispose to lactic acidosis (e.g., severe infection, shock); excessive alcohol intake.
| Precautions | Cardiovascular: increased risk of heart failure, fluid retention; hepatic: monitoring of liver enzymes required; renal: contraindicated in severe renal impairment (eGFR <30 mL/min/1.73 m²); lactic acidosis: risk factors include renal impairment, severe infection, alcohol abuse, hepatic disease; bladder cancer: possible association with pioglitazone; thyroid: possible increased risk of thyroid cancer; hypoglycemia: when used with insulin or sulfonylureas; impaired fertility in males; possible increased risk of bone fractures in females. |
Loading safety data…
| Start with the lowest available dose (15 mg/500 mg) once daily. Assess renal function before initiation and monitor eGFR frequently. Avoid use if eGFR < 45 mL/min/1.73 m². Use with caution due to increased risk of lactic acidosis, volume depletion, and bladder cancer (pioglitazone). Titrate slowly to minimize gastrointestinal side effects. |
| Fetal Monitoring | Monitor blood glucose, HbA1c, and signs of maternal hypoglycemia or lactic acidosis. Fetal monitoring with ultrasound and nonstress test as clinically indicated for gestational diabetes. Evaluate for signs of fluid retention or heart failure (pioglitazone). |
| Fertility Effects | Metformin may improve ovulation and fertility in women with polycystic ovary syndrome (PCOS). Pioglitazone may cause ovulatory menstrual cycles. No known negative effects on fertility in animal studies. |
| Food/Dietary | Take with food to minimize GI side effects. Avoid excessive alcohol intake due to increased risk of lactic acidosis with metformin. |
| Clinical Pearls | ACTOPLUS MET combines pioglitazone and metformin. Monitor liver enzymes before and during therapy due to pioglitazone risk of hepatotoxicity. Check renal function (eGFR ≥45 mL/min/1.73m²) for metformin. Avoid in heart failure (NYHA III/IV) due to pioglitazone. Watch for lactic acidosis symptoms. Titrate slowly to GI tolerance. |
| Patient Advice | Take with meals to reduce gastrointestinal upset. · Report symptoms of liver problems (nausea, abdominal pain, dark urine, jaundice). · Monitor for signs of lactic acidosis (fatigue, weakness, muscle pain, trouble breathing). · Avoid alcohol while taking this medication. · Notify your doctor if you become pregnant or plan to become pregnant. · Do not change your dose without consulting your doctor. · Tell all healthcare providers you are taking this medication, especially before surgery or imaging with contrast dyes. |