1Centre Research for Alimentary and Hepatobiliary System, Denpasar, Bali, Indonesia
2Faculty of Medicine of Udayana University, Denpasar, Bali, Indonesia
3Division of Gastroenterology and Hepatology, Department of Internal Medicine, Udayana University, Bali, Indonesia
4Division of Gastroenterology and Hepatology, Department of Internal Medicine, Udayana University/ Ngoerah Hospital, Bali, Indonesia
*Corresponding Author E-mail: mariadi@unud.ac.id
Online published on 14 May, 2025.
The escalating use of opioids in the management of cancer-induced pain has become notably prevalent. However, the prolonged use of opioids frequently gives rise to constipation. The primary approach to managing constipation involves the administration of oral laxatives with a combination of stool softeners, serving as the first-line therapeutic modalities. However, in individuals with chronic opioid use, leading to persistent constipation, reliance on laxatives may prove inadequate.
We searched literature from Pubmed, CENTRAL, Science Direct, and Google Scholar from January 2013 to September 2023. Relevant studies on the use of methylnaltrexone to treat OIC in cancer patients were collected. The random effect model was used in this study to evaluate size effects.
This study included six studies involving 1044 cancer patients with OIC. Methylnaltrexone increased laxations compared to placebo after 4 hours after the first dose in RCTs (OR 8.96, 95% CI 3.68 - 21.81, p < 0.00001). Cohort studies using proportional analysis found that the pooled rate was 71% (n= 2 studies, 95% CI 0.54 - 0.88). Methylnaltrexone also increased adverse events compared to placebo in RCTs (OR 2.48, 95% CI 1.24 - 4.98, p = 0.01). A pooled rate of 19% of adverse events in methylnaltrexone groups (n = 3 studies, 95% CI 0.00-0.43). Abdominal discomfort, gas accumulation, and feelings of nausea emerged as the top adverse events reported in RCTs. There were no significant differences in the change of baseline pain score after 4 hours of the first dose in both study groups. Also, there were no significant differences after 7 days post-dose in cancer patients (p = 0.704).
Despite the adverse events, Methylnaltrexone significantly triggered bowel movements within 4 hours after the first dose, compared to the placebo. Methylnaltrexone did not inhibit analgesic actions. Thus, it does not interfere main treatment for cancer pain.
Methylnaltrexone, Opioid-induced Constipation, Cancer, Laxations, Pain Score Changes
