Antimuscarinics trigger many side effects in patients with overactive bladders.
Approximately impacting 17% of the female population each year, overactive bladder syndrome (OAB) has been associated with decreased quality of life, low work productivity, and poor health status, according to the International Continence Society.
The primary prescribed pharmacological treatments for the condition are antimuscarinics like oxybutynin, tolterodine, and trospium, as they reportedly “depress” bladder contractions and inhibit “stimulation of the detrusor smooth muscle." However, researchers discovered that despite improving symptoms of OAB, antimuscarinics often triggered many unwanted side effects in patients with overactive bladders.
Previous studies had suggested antimuscarinics for OAB could contribute to some adverse central nervous system (CNS) effects, because all subtypes of muscarinic receptors were located through the body and brain: hippocampus, amygdala, and thalamus. The research team largely attributed the associations between antimuscarinics drug usage for OAB and diagnoses of depressive disorder to the drugs’ pharmacological and chemical properties.
Researchers had previously thought antimuscarinics for OAB would “selectively bind to muscarinic receptors located on the bladder detrusor muscle." However, some antimuscarinics for OAB with “high lipophilicity, neutral polarity, or low molecular size still cross the blood—brain barrier and further affect neurotransmission in the brain.” And, abnormal neurotransmission in the brain has been considered integral in the incidence of depressive disorder.
This retrospective cohort study led by Li-Ting Kao, senior author, assessed the relationship between the use of antimuscarinics and the subsequent risk of depressive disorder. Kao’s team used a population-based data set from the Taiwan Longitudinal Health Insurance Database 2005.
The cohort included 1952 women with OAB who were administered antimuscarinics. The team selected 9760 women with OAB who were not given antimuscarinics as the comparison cohort. Both groups of women included women who were diagnosed with OAB from January 2001 to December 2010.
All the subjects were tracked for 3 years (starting from index date) to pinpoint who were subsequently diagnosed with depressive disorder. According to the results, compared to the patients with OAB who did not receive antimuscarinics, the adjusted hazard ratio (HR) for depressive disorder in women with OAB who received antimuscarinics was 1.38 (95% confidence interval [CI] 1.15-1.64).
Furthermore, the adjusted HRs for subsequent depressive disorder for OAB women 18-39, 40-59, and ≥60 years who received antimuscarinics were reported as 1.83 (95%CI, 1.27—2.64), 1.36 (95% CI, 1.03–1.81), and 1.16 (95% CI, 0.86–1.56), respectively, compared with those OAB women who were not given antimuscarinics.
Based on the results, the researchers concluded, “Women with OAB who received antimuscarinics had a significantly higher risk of subsequent depressive disorder compared with those OAB women who did not receive antimuscarinics.”
While further research is necessary, the study authors do urge clinicians to be mindful of the potential connection between the use of antimuscarinics and the noted symptoms of depressive disorder in women with OAB.
The study, “Antimuscarinic Use in Females With Overactive Bladder Syndrome Increases the Risk of Depressive Disorder: A 3-Year Follow-up Study,” was published in The Journal of Clinical Pharmacology.