The Norwegian trial randomized participants after detoxification. The US trial, in which some participants were randomized before completing detoxification, reported 79 (28%) induction failures for XR-NTX and 17 (6%) for BUP-NX.1 As a result, a per protocol analysis was completed with the 204 patients on XR-NTX and 270 patients on BUP-NX who were successfully inducted onto a study medication. The 24-week relapse rate was 52% (106) for XR-NTX and 56% (150) for BUP-NX (OR = 0.87; 95% CI, 0.60 to 1.25; P = .44).
Cravings, adverse events, and cost considerations
Patients reported cravings using a visual analog scale. At 12 weeks in both studies, the XR-NTX groups reported fewer cravings than the BUP-NX groups, although by the end of the 24-week US trial, no statistically significant difference in cravings was found between the 2 groups.1,2
The Norwegian trial found a difference between the XR-NTX and the BUP-NX groups in the percentage of nonserious adverse events such as nausea or chills (60.6% in the XR-NTX group vs 30.6% in the BUP-NX group; P < .001), and the US trial found a difference in total number of overdoses (64% of the total overdoses were in the XR-NTX group). Neither trial, however, reported a statistically significant difference in serious adverse events or fatal overdoses between the 2 groups.1,2
The price for naltrexone is $1665.06 per monthly injection.3 The price for buprenorphine-naloxone varies depending on dose and formulation, with a general range of $527 to $600 per month at 16 mg/d.4
Editor’s takeaway
Two higher-quality RCTs show similar but imperfect effectiveness for both XR-NTX and daily sublingual BUP-NX. Injectable naltrexone’s higher cost may influence medication choice.