Influence of calcium channel blockers in patients with gastrointestinal disease in Japanese community pharmacies.

WHAT IS KNOWN AND OBJECTIVE

Calcium channel blockers (CCBs), which have been widely used for the treatment of hypertension and angina pectoris, decrease lower oesophageal sphincter pressure and, as a result, can exacerbate gastrointestinal disease. In a previous study, increased risk of exacerbation of gastrointestinal disease among elderly patients following treatment with CCBs was identified. The prevalence of gastrointestinal diseases has increased in elderly patients, and it is possible that treatment with CCBs may have undesirably influenced this increase. The change in risk of gastrointestinal disease can be estimated by analysing changes in the prescription of antisecretory drugs as an outcome of exacerbation of gastrointestinal disease caused by CCBs.

METHODS

It was hypothesized that patients who were prescribed CCBs would also change their use of antisecretory drugs. From September 2005 to August 2009, a dynamic retrospective cohort study was performed at five community pharmacies in Nagasaki, Japan, to assess alteration of antisecretory drug therapy following treatment with CCBs. Correlations with alterations of antisecretory drug therapy were determined by the Cox proportional hazards model.

RESULTS AND DISCUSSION

The proposed study included 260 patients who were prescribed CCBs and 155 controls. During the study period, 53 patients were prescribed CCBs and 13 controls altered their antisecretory drug therapy; the hazard ratio was 2·22 (95% CI 1·25-4·26).

WHAT IS NEW AND CONCLUSION

Calcium channel blocker treatment of patients with gastrointestinal disease was associated with alteration in frequency of prescription and an increase in dosage of antisecretory drugs. For clinical management of hypertension, alternative antihypertensive drugs may be considered for patients with gastrointestinal diseases. Further studies are required to determine the influence of CCB therapy on gastroesophageal diseases, suggested by the increase in use of antisecretory drugs.