ACTOS
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ACTOS (ACTOS).
Pioglitazone is a thiazolidinedione that selectively stimulates the peroxisome proliferator-activated receptor gamma (PPARγ). This leads to increased insulin sensitivity in adipose tissue, skeletal muscle, and liver, promoting glucose utilization and reducing hepatic gluconeogenesis.
| Metabolism | Primarily metabolized by CYP2C8 and CYP3A4 to active and inactive metabolites |
| Excretion | Primarily hepatic metabolism via CYP2C8 and CYP3A4, with biliary excretion of metabolites. Renal excretion: 15-30% unchanged as pioglitazone-related metabolites; <2% as parent drug. Fecal excretion: 55-60% as metabolites. |
| Half-life | Terminal elimination half-life: 3–7 hours for parent drug; metabolites (M-III and M-IV) have half-lives of 16–24 hours. Steady-state achieved after 7 days, allowing once-daily dosing. |
| Protein binding | >99% bound; primarily to serum albumin. Binds to other proteins with high affinity. |
| Volume of Distribution | Vd/F: 0.25 L/kg (0.63 L/kg based on weight). Indicates distribution into total body water and peripheral tissues, including adipose and muscle. |
| Bioavailability | Oral: 83% (absolute); food delays absorption but does not reduce extent. No other routes of administration clinically relevant. |
| Onset of Action | Oral: 2–4 weeks for initial reduction in fasting plasma glucose; maximal effect may require 8–12 weeks. No immediate clinical effect. |
| Duration of Action | Duration: 24 hours due to active metabolites; supports once-daily dosing. Effects on insulin sensitivity persist with continued treatment. |
15 to 30 mg orally once daily; maximum 45 mg once daily.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for renal impairment including end-stage renal disease; not removed by hemodialysis. |
| Liver impairment | Contraindicated in Child-Pugh Class C; use with caution in Child-Pugh Class B; no data for Class A. |
| Pediatric use | Not recommended; safety and efficacy not established in patients under 18 years. |
| Geriatric use | Initiate at 15 mg once daily; titrate slowly due to increased risk of edema and heart failure. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ACTOS (ACTOS).
| Breastfeeding | Pioglitazone is excreted in rat milk, but no human lactation data exist. The M/P ratio is unknown. Due to potential for adverse effects in nursing infants (e.g., hypoglycemia, weight gain), breastfeeding is generally not recommended during therapy. Consider alternative agents if breastfeeding is intended. |
| Teratogenic Risk | FDA Pregnancy Category C. In animal studies, pioglitazone caused delayed parturition, embryotoxicity, and decreased fetal weights at doses >2 times the maximum recommended human dose (MRHD). Human data are limited. Pioglitazone may cause fetal harm, particularly during the second and third trimesters, due to its effects on insulin resistance and potential for placental insufficiency. Use only if benefit outweighs risk. |
■ FDA Black Box Warning
May cause or exacerbate congestive heart failure. Not recommended in patients with symptomatic heart failure. Discontinue if deterioration in cardiac status occurs.
| Serious Effects |
["NYHA Class III or IV heart failure","Hypersensitivity to pioglitazone or any component","Active bladder cancer or history of bladder cancer"]
| Precautions | ["Fluid retention and heart failure","Hepatotoxicity (rare but serious; monitor liver enzymes)","Increased risk of fractures (especially in women)","Ovulation induction in premenopausal anovulatory women (risk of pregnancy)","Hypoglycemia when used with insulin or sulfonylureas","Macular edema (reported postmarketing)"] |
| Food/Dietary | No significant food interactions. Take with or without meals. Avoid excessive alcohol intake due to hepatotoxicity risk. |
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| Fetal Monitoring | Monitor maternal blood glucose and HbA1c throughout pregnancy. Assess fetal growth via ultrasound to detect macrosomia or intrauterine growth restriction. Monitor for maternal hypoglycemia, particularly if combined with insulin. Consider fetal echocardiography due to potential cardiac effects (limited data). Postpartum, monitor neonatal glucose levels. |
| Fertility Effects | Pioglitazone may restore ovulation in anovulatory women with polycystic ovary syndrome (PCOS) due to improved insulin sensitivity. This can increase the risk of unintended pregnancy. Conversely, no adverse effects on male or female fertility have been reported in animal studies at clinically relevant doses. |
| Clinical Pearls | Monitor liver enzymes before initiation and periodically; contraindicated in active liver disease or ALT >2.5x ULN. Use with caution in patients with edema/CHF; can cause fluid retention. May cause or exacerbate macular edema, perform eye exams if visual disturbances occur. Avoid in patients with NYHA Class III/IV heart failure. Weight gain and bone fractures (especially in women) are notable long-term effects. |
| Patient Advice | Take once daily with or without food. Swallow tablet whole; do not crush or chew. · Report any signs of liver problems: nausea, vomiting, abdominal pain, dark urine, or yellowing of skin/eyes. · Notify your doctor if you experience unusual weight gain, swelling, or shortness of breath (signs of fluid retention). · Blurred vision or vision changes require immediate medical evaluation. · This drug can cause ovulation in women with polycystic ovary syndrome; discuss contraceptive needs. · Monitor blood sugar regularly and carry glucose for treating hypoglycemia if used with insulin or sulfonylureas. · Report any bone pain or fractures; risk of fractures is increased, especially in women. · Avoid alcohol consumption due to increased risk of liver toxicity. |