Go to content

Extended-release nifedipine and the risk of intestinal obstruction: a population-based study


Objectives —To examine the risk of bowel obstruction in older adults during treatment with extended-release nifedipine compared with patients treated with amlodipine.

Design — Retrospective cohort study using multiple linked healthcare databases.

Setting — Ontario, Canada from 1 April 1997 to 31 December 2010

Participants — The authors identified patients aged 66 years and older who started treatment with Adalat XL, an extended-release nifedipine product employing a tablet delivery system associated with mechanical bowel obstruction. For comparison, the authors studied patients receiving amlodipine, a long-acting calcium channel blocker that does not utilise the same delivery system and has not been implicated as a cause of bowel obstruction. Propensity score matching was used to ensure similarity of patients receiving the two drugs.

Primary outcome measure — HR for the association between extended-release nifedipine relative to amlodipine and hospitalisation for bowel obstruction during therapy.

Results — Over the 13-year study period, the authors identified 103 657 patients treated with extended-release nifedipine and 204 733 patients treated with amlodipine. In these two groups, 591 (0.6%) and 1185 (0.6%) of patients were hospitalised for bowel obstruction, respectively. The authors found no difference in the risk of bowel obstruction among patients treated with extended-release nifedipine compared with amlodipine (HR 1.09, 95% CI 0.96 to 1.24).

Conclusions — Bowel obstruction during treatment with extended-release nidefipine is rare, and the risk is not appreciably greater than that during treatment with amlodipine.



Juurlink DN, Hellings C, Gomes T, Huang A, Paterson JM, Urbach DR, Mamdani MM; for the Canadian Drug Safety and Effectiveness Research Network (CDSERN). BMJ Open. 2014; 4(7):e005377. Epub 2014 Jul 24.

View Source