Pioglitazone

Additional information

Pharmacokinetics and dosing

According to the original manufacturer, the mean Cmax and AUC values of pioglitazone is increased 20-60% in women compared to men and HbA1c decreases from baseline were generally greater for women than for men [1]. However, other studies (one study 61 men, 63 women, the other 18 men, 19 women) report only small or non-significant sex differences in Cmax and AUC [2, 3].

Although some studies report sex differences in pioglitazone pharmacokinetics [1, 2], no dose adjustment is necessary based on sex alone. However, the therapy should be individualized for each patient to achieve good glycemic control. High pioglitazone doses are associated with greater risk of fracture in women aged 50 years and older, but not in men or women under 50 years of age [4].

Effects

A meta-analysis examining factors associated with reduction in HbA1c from rosiglitazone and pioglitazone, found no impact of sex on the effect size of glitazone therapy on HbA1c [5]. Only pioglitazone is available in Sweden.

A small study in Japanese patients (22 men, 26 women) with type 2 diabetes, showed that pioglitazone is likely to show favorable effects on blood glucose control especially in women with higher fasting plasma glucose levels. More women were in the responder group (18 women vs. 4 men). The responders were those showing >1% of reduction in HbA1c after 12 weeks of treatment with pioglitazone 15 mg/day [6].

Adverse effects

Glitazones (pioglitazone, rosiglitazone, troglitazone) have been associated with increased fracture risk. However, results from studies have been inconsistent [7]. Some studies have reported an increased risk only in women (odds ratios varying 1.56-2.23) [4, 8-10], while other studies have reported similar risk in fracture in men and women [11-14]. However, the clinical significance is unclear, clinical trials are relatively small and men have a lower baseline risk of fracture than women [9]. One systematic review of 5 randomized controlled trials (7001 men, 4400 women) reported an increased risk of fractures among women (odds ratio 2.23) but not among men (odds ratio 1.00) treated with pioglitazone or rosiglitazone [15]. One study (48074 men, 36266 women) found that pioglitazone treatment was more strongly associated with fractures than rosiglitazone, in both men and women [14]. Only pioglitazone is available in Sweden.A meta-analysis (in total 2 321 085 patients) reports an increased incidence of bladder cancer after pioglitazone therapy in men. The mechanisms by which the exposure to pioglitazone causes bladder cancer remain incompletely understood [16].

Reproductive health issues

Regarding teratogenic aspects, please consult the Drugs and Birth Defects Database (in Swedish, Janusmed fosterpåverkan).

Other information

The influence of pioglitazone on body composition in older non-diabetic overweight/obese men and women during weight loss has been examined (48 men, 40 women, 65-79 years). Pioglitazone reduced abdominal visceral fat in men but not in women. Loss of subcutaneous fat in thigh was attenuated in women taking pioglitazone. This sex differences can be explained by differences in adipose tissue loss from the visceral and subcutaneous compartments during weight-loss trials [17].