A prospective, comparative study of the occurrence and severity of constipation with darifenacin and trospium in overactive bladder.

Introduction: Darifenacin and trospium are the commonly used antimuscarinics in the management of overactive bladder (OAB). Constipation is the second most common treatment related side-effect. Though its incidence with the above two medications is known, data on their comparative severity and impact on patient's well-being is lacking.

Materials And Methods: Sixty subjects with OAB included in the study were randomized in 1:1 fashion to receive either darifenacin 7.5 mg OD or trospium extended release 60 mg OD. Treatment response was monitored using overactive bladder symptom score (OABSS). The severity of constipation was assessed using McMillan & Williams Constipation assessment scale (CAS), Bristol stool form scale and Knowles-Eccersley-Scott-Symptom (KESS) questionnaire score administered at baseline, 2 and 4 weeks of treatment.

Results: OABSS improved significantly, -5.80 ± 3.99 (p = 0.0005) and -5.27 ± 2.98 (p = 0.0005) in darifenacin and trospium groups respectively. However, the difference between the two groups was not significant either at 2 weeks (p = 0.952) or 4 weeks (p = 0.654) of treatment. A significant decrease in stool consistency was noted with darifenacin treatment (p < 0.05), but the same was not seen with trospium (p = 0.076). There was no significant difference in scores of KESS questionnaire between baseline, 2 weeks and 4 weeks, both within the group and between the groups (p > 0.05). McMillan & Williams CAS scores increased at week 2 and week 4, in comparison with baseline scores in both darifenacin and trospium treated patients, however, the difference between the two groups was not statistically significant (p > 0.05).

Conclusion: Darifenacin and trospium are equally efficacious and comparable in tolerability in terms of constipation severity and its impact on patient well-being.