Background: Opioid analgesics possess a number of side effects, among which constipation and nausea/vomiting occur most frequently. Although pretreatment with laxatives and antiemetics for the prophylaxis of opioid-induced constipation and nausea/vomiting, respectively, is recommended, such side effects are still a matter of concern in clinical setting.
Methods: We first surveyed the prevalence of premedication in 83 cancer patients who took opioid analgesics and the incidence of such side effects. Subsequently, intervention was carried out to promote premedication, and the effectiveness of the intervention was evaluated in 107 patients.
Results: Prophylactic treatment with laxatives and antiemetics were conducted in 57% and 52%, respectively. The most frequently prescribed laxatives and antiemetics were magnesium oxide in combination with pantethine, a mild stimulant laxative, and prochlorperazine, respectively. The lack of premedication increased the risk of constipation (odds ratio, 5.25; 95% confidence intervals, 1.93-14.31; p = 0.001) and vomiting (4.67, 1.04-21.04; p = 0.045). Intervention such as provision of drug information to physicians, verification of prescription orders, and instructions to patients increased the rates of prophylactic medications to 93% (p < 0.001) for laxatives and 81% (p < 0.001) for antiemetics. The incidence of side effects was lowered from 36% to 9% (p < 0.001) for constipation, from 28% to 17% for nausea (p = 0.077), and from 16% to 4% for vomiting (p = 0.0085).
Conclusion: Intervention to promote prophylactic medication was highly effective in reducing the risk of opioid-induced constipation and nausea/vomiting.