New Drug Deemed Effective for Opioid-Induced Constipation

With 259 million painkiller prescriptions written in 2012 alone, according to the Centers for Disease Control and Prevention (CDC), one of the most common side effects experienced by patients being treated for chronic pain is opioid-induced constipation (OIC).

Although there are medications available to treat OIC, one concern is that using them will make the patient’s opioids less effective against pain. However, a collaborative team may have discovered a new drug that provides gastroenterological benefits without inhibiting the analgesic effects from the painkillers. In a recent study, the safety and efficacy of naloxone sustained release (NSR) capsules were evaluated when compared to a placebo.

Previous research estimated that 40% of patients with non-malignant pain experience OIC, which does not resolve with continued use like many other opioid side effects. In this phase II study, NSR was provided to40 patients experiencing pain and OIC. They were randomly split into 4 cohorts and each was assigned a different NSR dosage — 2.5 mg, 5 mg, 10 mg, and 20 mg. The medication was prescribed to be taken once per day for 3 weeks and then twice per day for weeks 4 to 6. Published in Pain Medicine, the results were compared to a placebo group.

The team found “significant improvements” in spontaneous bowl movements (SBM) for the groups assigned 5 mg, 10 mg, and 20 mg of NSR.

“The incidence of adverse events amount the 4 active treatment groups were similar,” the team verified.

Although the number of severe adverse events was low across all of the groups, the highest amount of incidences were witnessed in the placebo group. Furthermore, none of the patients showed noteworthy changes in opioid withdrawal when measured using the Subjective Opioid Withdrawal Scale and Clinical Opioid Withdrawal Scale. The team noted that pain did not increase with the use of NSR which indicates that it does not inhibit the effectiveness of painkillers.

“[The research] has shown that using a new sustained release formulation to deliver oral naloxone to the colon allows successful treatment of OIC without comprising the desired opioid effects,” the authors confirmed.