Women who take antimuscarinics for overactive bladder syndrome face an increased risk of depressive disorders, researchers from Taiwan report.

Antimuscarinics, including oxybutynin, tolterodine, and trospium, are commonly used to treat overactive bladder syndrome, but several unwanted side effects accompany their use. The association between antimuscarinic use and depressive disorder remains unclear.

Dr. Herng–Ching Lin from Taipei Medical University Hospital and colleagues investigated the possible association between antimuscarinics and the subsequent risk of depressive disorder in a retrospective cohort study of women with overactive bladder syndrome in the Taiwan Longitudinal Health Insurance database.

The incidence of depressive disorder per 100 person–years during 3 years of follow–up was 2.77 among 1,952 women who received antimuscarinics versus 2.02 among 9,760 matched women who did not receive antimuscarinics.

After adjusting for other factors, the risk of depressive disorder was 38% higher for women who received antimuscarinics than for women who did not, according to the April 5th online report in The Journal of Clinical Pharmacology.

The adjusted risk of depressive disorder was 93% higher among women who were regular antimuscarinic users and 23% higher among women who were irregular users, compared with women who had never been prescribed antimuscarinics.

The association between antimuscarinic use and depressive disorder risk was apparent among women ages 18 to 59, but the association lost significance among women aged 60 and older.

Most patients in this study were of Chinese ethnicity, and it’s unclear whether the findings are generalizable to other ethnic populations, the authors say. “We recommend that clinicians be alert to the relationship between antimuscarinics and depressive disorder in overactive bladder syndrome (OAB) women,” they conclude. “In addition, clinicians can provide appropriate instructions for OAB women who receive antimuscarinics to seek health and medical services as soon as possible if they have relevant clinical symptoms of depressive disorder.”

“However,” the researchers add, “future experimental studies are still required to identify the potential mechanisms for the association between antimuscarinic use and depressive disorder in OAB women.”

Dr. Lin did not respond to a request for comments.