Actos (pioglitazone) Side Effects, Warnings, and Drug Interactions

Actos (pioglitazone) is in a class of anti-diabetic drugs called thiazolidinediones used to treat type 2 diabetes in adults. It is used along with a healthy diabetic diet, regular exercise, weight control, smoking reduction, and careful monitoring of blood glucose. Actos may be used alone or in combination with other drugs that also lower blood glucose.

Common side effects of Actos include:

• upper respiratory tract infection,
• headache,
• sinusitis,
• muscle aches,
• tooth disorders,
• low blood sugar (hypoglycemia),
• and sore throat.

Serious side effects of Actos include:

• anemia,
• liver injury (symptoms include nausea, vomiting, abdominal pain, fatigue, loss of appetite, dark urine),
• fluid retention (edema),
• fractures,
• bladder cancer,
• diabetic macular edema,
• and reduced red blood cells.

Drug interactions of Actos include gemfibrozil or other drugs that reduce the activity of liver enzymes that break down Actos and rifampin. 

There are no adequate studies of Actos in pregnant women. Actos may be used in pregnancy if the physician feels the potential risks are justified. It is unknown if Actos is secreted in breast milk and its effects on nursing infants are unknown. Consult your doctor before breastfeeding.

WARNING

• Actos and similar drugs can cause or worsen congestive heart failure in some patients.
• Patients should be monitored for signs and symptoms of heart failure at the beginning of treatment and after dose increases. For example:
  • excessive, rapid weight gain,
  • dyspnea,
  • and/or edema.
• Actos is not recommended for patients with symptomatic heart failure and patients with established New York Heart Association (NYHA) Class III or IV heart failure should not use Actos.

Other side effects of Actos

The most common side effects of Actos alone or in combination with sulfonylureas, metformin, or insulin are:

• Upper respiratory tract infection
• Headache
• Sinusitis
• Muscle aches
• Tooth disorders
• Hypoglycemia (low blood sugar)
• Sore throat

Possible serious side effects of Actos include:

• Anemia
• Liver injury
• Edema
• Fractures
• Bladder cancer
• Diabetic macular edema

Dose-related fluid accumulation (edema) can occur especially when combined with insulin. Fluid accumulation can worsen or lead to heart failure. Actos should not be used in patients with heart disease classified by the New York Heart Association (NYHA) as Class III and IV heart failure or symptomatic heart failure.

Fluid accumulation also may lead to macular edema, resulting in reduced vision. Actos also can reduce red blood cells.

There have been post-marketing reports of liver failure while taking Actos.

Actos has been associated with liver injury. Periodic monitoring of liver-related side effects and liver tests should be conducted in patients taking Actos.

Symptoms of liver injury are:

• Nausea
• Vomiting
• Abdominal pain
• Fatigue
• Anorexia (loss of appetite)
• Dark urine

Actos should be stopped if patients have symptoms of liver injury and liver function test results that are greater than three times the normal level. Liver blood tests are obtained before starting treatment. Monitoring liver tests during treatment is not recommended for patients without liver disease.

Actos may cause ovulation in women who have stopped ovulating if they are premenopausal and insulin resistant. This may lead to pregnancy. For women (but not men) taking Actos, there is an increased risk of bone fractures of the distal bones of the arm and leg. Patients taking Actos should maintain proper bone health.

The following serious adverse reactions are discussed elsewhere in the labeling:

• Congestive heart failure
• Edema
• Fractures

Clinical Trials Experience

• Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
• Over 8500 patients with type 2 diabetes have been treated with Actos in randomized, double-blind, controlled clinical trials, including 2605 patients with type 2 diabetes and macrovascular disease treated with Actos in the PROactive clinical trial.
• In these trials, over 6000 patients have been treated with Actos for six months or longer, over 4500 patients have been treated with Actos for one year or longer, and over 3000 patients have been treated with Actos for at least two years.
• In six pooled 16-to 26-week placebo-controlled monotherapy and 16-to 24-week add-on combination therapy trials, the incidence of withdrawals due to adverse events was 4.5% for patients treated with Actos and 5.8% for comparator-treated patients.
• The most common adverse events leading to withdrawal were related to inadequate glycemic control, although the incidence of these events was lower (1.5%) with Actos than with placebo (3.0%).
• In the PROactive trial, the incidence of withdrawals due to adverse events was 9.0% for patients treated with Actos and 7.7% for placebo-treated patients. Congestive heart failure was the most common serious adverse event leading to withdrawal occurring in 1.3% of patients treated with Actos and 0.6% of patients treated with placebo.

Common Adverse Events: 16-To 26-Week Monotherapy Trials

A summary of the incidence and type of common adverse events reported in three pooled 16to 26-week placebo-controlled monotherapy trials of Actos is provided in Table 1.

Terms that are reported represent those that occurred at an incidence of >5% and more commonly in patients treated with Actos than in patients who received placebo. None of these adverse events were related to Actos dose.

Table 1. Three Pooled 16-to 26-Week Placebo-Controlled Clinical Trials of Actos Monotherapy: Adverse Events Reported at an Incidence >5% and More Commonly in Patients Treated with Actos than in Patients Treated with Placebo

Common Adverse Events: 16-To 24-Week Add-On Combination Therapy Trials

A summary of the overall incidence and types of common adverse events reported in trials of Actos add-on to sulfonylurea is provided in Table 2. Terms that are reported represent those that occurred at an incidence of >5% and more commonly with the highest tested dose of Actos.

Table 2. 16-to 24-Week Clinical Trials of Actos Add-on to Sulfonylurea

A summary of the overall incidence and types of common adverse events reported in trials of Actos add-on to metformin is provided in Table 3. Terms that are reported represent those that occurred at an incidence of >5% and more commonly with the highest tested dose of Actos.

Table 3. 16-to 24-Week Clinical Trials of Actos Add-on to Metformin

Table 4 summarizes the incidence and types of common adverse events reported in trials of Actos add-on to insulin. Terms that are reported represent those that occurred at an incidence of >5% and more commonly with the highest tested dose of Actos.

Table 4. 16-to 24-Week Clinical Trials of Actos Add-on to Insulin

A summary of the overall incidence and types of common adverse events reported in the PROactive trial is provided in Table 5. Terms that are reported represent those that occurred at an incidence of >5% and more commonly in patients treated with Actos than in patients who received placebo.

Table 5. PROactive Trial: Incidence and Types of Adverse Events Reported in >5% of Patients Treated with Actos and More Commonly than Placebo

Congestive Heart Failure

A summary of the incidence of adverse events related to congestive heart failure is provided in Table 6 for the 16-to 24-week add-on to sulfonylurea trials, for the 16-to 24-week add-on to insulin trials, and for the 16-to 24-week add-on to metformin trials. None of the events were fatal.

Table 6. Treatment-Emergent Adverse Events of Congestive Heart Failure (CHF)

Patients with type 2 diabetes and NYHA class II or early class III congestive heart failure were randomized to receive 24 weeks of double-blind treatment with either Actos at daily doses of 30 mg to 45 mg (n=262) or glyburide at daily doses of 10 mg to 15 mg (n=256). A summary of the incidence of adverse events related to congestive heart failure reported in this study is provided in Table 7.

Table 7. Treatment-Emergent Adverse Events of Congestive Heart Failure (CHF) in Patients with NYHA Class II or III Congestive Heart Failure Treated with Actos or Glyburide

Congestive heart failure events leading to hospitalization that occurred during the PROactive trial are summarized in Table 8.

Table 8. Treatment-Emergent Adverse Events of Congestive Heart Failure (CHF) in PROactive Trial

Cardiovascular Safety

• In the PROactive trial, 5238 patients with type 2 diabetes and a history of macrovascular disease were randomized to Actos (N=2605), force-titrated up to 45 mg daily or placebo (N=2633) in addition to standard of care.
• Almost all patients (95%) were receiving cardiovascular medications (beta blockers, ACE inhibitors, angiotensin II receptor blockers, calcium channel blockers, nitrates, diuretics, aspirin, statins and fibrates).
• At baseline, patients had a mean age of 62 years, mean duration of diabetes of 9.5 years, and mean HbA1c of 8.1%.
• Mean duration of follow-up was 34.5 months.
• The primary objective of this trial was to examine the effect of Actos on mortality and macrovascular morbidity in patients with type 2 diabetes mellitus who were at high risk for macrovascular events.
• The primary efficacy variable was the time to the first occurrence of any event in a cardiovascular composite endpoint that included all-cause mortality, nonfatal myocardial infarction (MI) including silent MI, stroke, acute coronary syndrome, cardiac intervention including coronary artery bypass grafting or percutaneous intervention, major leg amputation above the ankle, and bypass surgery or revascularization in the leg.
• A total of 514 (19.7%) patients treated with Actos and 572 (21.7%) placebo-treated patients experienced at least one event from the primary composite endpoint (hazard ratio 0.90; 95% Confidence Interval: 0.80, 1.02; p=0.10).
• Although there was no statistically significant difference between Actos and placebo for the three-year incidence of a first event within this composite, there was no increase in mortality or in total macrovascular events with Actos.
• The number of first occurrences and total individual events contributing to the primary composite endpoint is shown in Table 9.

Table 9. PROactive: Number of First and Total Events for Each Component within the Cardiovascular Composite Endpoint

Weight Gain

• Dose-related weight gain occurs when Actos is used alone or in combination with other antidiabetic medications.
• The mechanism of weight gain is unclear but probably involves a combination of fluid retention and fat accumulation.
• Tables 10 and 11 summarize the changes in body weight with Actos and placebo in the 16to 26-week randomized, double-blind monotherapy and 16-to 24-week combination add-on therapy trials and in the PROactive trial.

Table 10. Weight Changes (kg) from Baseline During Randomized, Double-Blind Clinical Trials

Table 11. Median Change in Body Weight in Patients Treated with Actos Versus Patients Treated with Placebo During the Double-Blind Treatment Period in the PROactive Trial

Edema

• Edema induced from taking Actos is reversible when Actos is discontinued. The edema usually does not require hospitalization unless there is coexisting congestive heart failure.
• A summary of the frequency and types of edema adverse events occurring in clinical investigations of Actos is provided in Table 12.

Table 12. Adverse Events of Edema in Patients Treated with Actos

Table 13. Adverse Events of Edema in Patients in the PROactive Trial

Hepatic Effects

• There has been no evidence of induced hepatotoxicity with Actos in the Actos controlled clinical trial database to date.
• One randomized, double-blind 3-year trial comparing Actos to glyburide as add-on to metformin and insulin therapy was specifically designed to evaluate the incidence of serum ALT elevation to greater than three times the upper limit of the reference range, measured every eight weeks for the first 48 weeks of the trial then every 12 weeks thereafter.
• A total of 3/1051 (0.3%) patients treated with Actos and 9/1046 (0.9%) patients treated with glyburide developed ALT values greater than three times the upper limit of the reference range.
• None of the patients treated with Actos in the Actos controlled clinical trial database to date have had a serum ALT greater than three times the upper limit of the reference range and a corresponding total bilirubin greater than two times the upper limit of the reference range, a combination predictive of the potential for severe drug-induced liver injury.

Hypoglycemia

• In the Actos clinical trials, adverse events of hypoglycemia were reported based on clinical judgment of the investigators and did not require confirmation with fingerstick glucose testing.
• In the 16-week add-on to sulfonylurea trial, the incidence of reported hypoglycemia was 3.7% with Actos 30 mg and 0.5% with placebo.
• In the 16-week add-on to insulin trial, the incidence of reported hypoglycemia was:
  • 7.9% with Actos 15 mg,
  • 15.4% with Actos 30 mg,
  • and 4.8% with placebo.
• The incidence of reported hypoglycemia was higher with Actos 45 mg compared to Actos 30 mg in both the 24-week add-on to sulfonylurea trial (15.7% vs. 13.4%) and in the 24-week add-on to insulin trial (47.8% vs. 43.5%).
• Three patients in these four trials were hospitalized due to hypoglycemia. All three patients were receiving Actos 30 mg (0.9%) in the 24-week add-on to insulin trial.
• An additional 14 patients reported severe hypoglycemia (defined as causing considerable interference with patient’s usual activities) that did not require hospitalization.
• These patients were receiving Actos 45 mg in combination with sulfonylurea (n=2) or Actos 30 mg or 45 mg in combination with insulin (n=12).

Urinary Bladder Tumors

• Tumors were observed in the urinary bladder of male rats in the two-year carcinogenicity study.
• During the three year PROactive clinical trial, 14 patients out of 2605 (0.54%) randomized to Actos and 5 out of 2633 (0.19%) randomized to placebo were diagnosed with bladder cancer.
• After excluding patients in whom exposure to study drug was less than one year at the time of diagnosis of bladder cancer, there were 6 (0.23%) cases on Actos and two (0.08%) cases on placebo.
• After completion of the trial, a large subset of patients was observed for up to 10 additional years, with little additional exposure to Actos.
• During the 13 years of both PROactive and observational follow-up, the occurrence of bladder cancer did not differ between patients randomized to Actos or placebo (HR =1.00; 95% CI: 0.59-1.72).

Laboratory Abnormalities

Hematologic Effects

• Actos may cause decreases in hemoglobin and hematocrit.
• In placebo-controlled monotherapy trials, mean hemoglobin values declined by 2% to 4% in patients treated with Actos compared with a mean change in hemoglobin of -1% to +1% in placebo-treated patients.
• These changes primarily occurred within the first 4 to 12 weeks of therapy and remained relatively constant thereafter.
• These changes may be related to increased plasma volume associated with Actos therapy and are not likely to be associated with any clinically significant hematologic effects.

Creatine Phosphokinase

• During protocol-specified measurement of serum creatine phosphokinase (CPK) in Actos clinical trials, an isolated elevation in CPK to greater than 10 times the upper limit of the reference range was noted in nine (0.2%) patients treated with Actos (values of 2150 to 11400 IU/L) and in no comparator-treated patients.
• Six of these nine patients continued to receive Actos, two patients were noted to have the CPK elevation on the last day of dosing and one patient discontinued Actos due to the elevation.
• These elevations resolved without any apparent clinical sequelae.
• The relationship of these events to Actos therapy is unknown.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of Actos.

Because these reactions are reported voluntarily from a population of uncertain size, it is generally not possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

• New onset or worsening diabetic macular edema with decreased visual acuity.
• Fatal and nonfatal hepatic failure.

Postmarketing reports of congestive heart failure have been reported in patients treated with Actos, both with and without previously known heart disease and both with and without concomitant insulin administration.

In postmarketing experience, there have been reports of unusually rapid increases in weight and increases in excess of that generally observed in clinical trials. Patients who experience such increases should be assessed for fluid accumulation and volume-related events such as excessive edema and congestive heart failure.

Strong CYP2C8 Inhibitors

An inhibitor of CYP2C8 (e.g., gemfibrozil) significantly increases the exposure (area under the serum concentration-time curve or AUC) and half-life (t_½) of pioglitazone. Therefore, the maximum recommended dose of Actos is 15 mg daily if used in combination with gemfibrozil or other strong CYP2C8 inhibitors.

CYP2C8 Inducers

An inducer of CYP2C8 (e.g., rifampin) may significantly decrease the exposure (AUC) of pioglitazone. Therefore, if an inducer of CYP2C8 is started or stopped during treatment with Actos, changes in diabetes treatment may be needed based on clinical response without exceeding the maximum recommended daily dose of 45 mg for Actos.

Topiramate

A decrease in the exposure of pioglitazone and its active metabolites were noted with concomitant administration of pioglitazone and topiramate. The clinical relevance of this decrease is unknown; however, when Actos and topiramate are used concomitantly, monitor patients for adequate glycemic control.