Thiazolidinedione (PPAR-γ Agonist) Pregnancy: Pioglitazone should not be used in pregnancy — there are no adequate human data to determine safety, and foetal growth restriction was apparent in animal studies. It should not be administered to breast-feeding women (pioglitazone is present in the milk of lactating rats; excretion in human milk is unknown). Animal fertility studies showed no effect on copulation, impregnation or fertility index.

Pioglitazone

Brand names: Actos

Pioglitazone is a thiazolidinedione (glitazone) used in type 2 diabetes, usually as add-on therapy; it improves insulin sensitivity without causing hypoglycaemia alone.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 15 mg or 30 mg once daily at initiation; the dose may be increased in increments up to 45 mg once daily

Route: Oral

Frequency: Once daily

Max: 45 mg once daily

Administration: taken orally once daily with or without food; tablets should be swallowed with a glass of water. Combination with insulin: the current insulin dose can be continued when pioglitazone is started; if the patient reports hypoglycaemia the insulin dose should be decreased (the US labelling in the same bundle suggests decreasing insulin by 10% to 25%, and reducing the dose of an insulin secretagogue such as a sulfonylurea if hypoglycaemia occurs). Elderly: no dose adjustment is necessary, but physicians should start with the lowest available dose and increase gradually, particularly when pioglitazone is used with insulin, because of the increased risk of serious heart failure; the balance of benefit and risk (bladder cancer, fractures, heart failure) should be considered carefully before and during treatment. Hepatic impairment: pioglitazone should not be used (also a contraindication). Paediatric: safety and efficacy in children and adolescents under 18 years have not been established; no data are available. Monitoring: assess bladder cancer risk factors before initiating; monitor for signs and symptoms of heart failure, weight gain and oedema after initiation and after any dose increase. ADDITIONAL FROM US LABELLING IN THE SAME BUNDLE (not in the fetched UK SPC §4.2): limit the initial dose to 15 mg once daily in patients with NYHA Class I or II heart failure (note the UK SPC contraindicates cardiac failure or a history of cardiac failure, NYHA I to IV); and limit the maximum dose to 15 mg daily when used with gemfibrozil or other strong CYP2C8 inhibitors.

Dose adjustments

Renal

No dose adjustment is necessary in patients with impaired renal function. NOTE: the fetched SPC text reads 'creatinine clearance > 4 ml/min' — this figure appears garbled in the source and must be verified against the current SPC before publication. No information is available from dialysed patients, therefore pioglitazone should not be used in such patients.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Initiate pioglitazone tablets at 15 mg or 30 mg once daily. Limit initial dose to 15 mg once daily in patients with NYHA Class I or II heart failure. (2.1) If there is inadequate glycemic control, the dose can be increased in 15 mg increments up to a maximum of 45 mg once daily. (2.1) Obtain liver tests before starting pioglitazone tablets. If abnormal, use caution when treating with pioglitazone tablets, investigate the probable cause, treat (if possible) and follow appropriately. Monitoring liver tests while on pioglitazone tablets are not recommended in patients without liver disease. ( 5.3 ) 2.1 Recommendations for All Patients Pioglitazone tablets should be taken once daily and can be …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2025-05-17. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Cardiac failure or history of cardiac failure (NYHA stages I to IV)
Hepatic impairment
Diabetic ketoacidosis
Current bladder cancer or a history of bladder cancer
Uninvestigated macroscopic haematuria

Side effects

Oedema (very common in monotherapy)
Weight increased (common across all regimens)
Hypoglycaemia (very common in combination with sulphonylurea; common with metformin plus sulphonylurea and with insulin)
Bone fracture (common across all regimens, increased incidence in female patients)
Upper respiratory tract infection (common) and hypoaesthesia (common)
Heart failure (common in combination with insulin); bladder cancer (uncommon); visual disturbance and macular oedema

Interactions

Strong CYP2C8 inhibitors (e.g. gemfibrozil) — increase pioglitazone exposure approximately 3-fold; limit the pioglitazone dose to a maximum of 15 mg daily
CYP2C8 inducers (e.g. rifampicin) — may significantly decrease pioglitazone exposure; diabetes treatment may need changing based on clinical response, without exceeding the maximum 45 mg daily
Topiramate — decreases exposure to pioglitazone and its active metabolites; clinical relevance unknown
Insulin — concomitant use increases the risk of oedema and post-marketing cases of cardiac failure have been reported; observe for signs and symptoms of heart failure, weight gain and oedema (§4.4)
NSAIDs including selective COX-2 inhibitors — post-marketing cases of peripheral oedema and cardiac failure reported with concomitant use (§4.4)
(NOTE: eMC §4.5 was not captured in the bundle; the CYP2C8 and topiramate entries are from section 7 of the US prescribing information in the same bundle)

Clinical monograph

How it works

It activates PPAR-gamma nuclear receptors, increasing peripheral insulin sensitivity and glucose uptake.

Prescribing in practice

It causes fluid retention and can precipitate or worsen heart failure — avoid in heart failure or a history of it.
It is associated with a small increased risk of bladder cancer (avoid with active or past bladder cancer or unexplained haematuria) and with fractures.
It can cause weight gain and, rarely, hepatotoxicity; the effect builds over weeks.

Monitoring

Monitor HbA1c, weight and for signs of fluid overload/heart failure; check liver function if indicated; review the benefit periodically.

Counselling the patient

Report breathlessness, ankle swelling or rapid weight gain (fluid retention).
Report blood in the urine.
It does not usually cause low blood sugar on its own.

Evidence & guidelines

An option to intensify type 2 diabetes treatment (NICE NG28), avoided in heart failure and weighed against bladder-cancer and fracture risk.

Reference: PROACTIVE Trial (Dormandy et al, Lancet 2005); PIVENS Trial (Sanyal et al, NEJM 2010); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways