Lofexidine Effective for Opioid Withdrawal Symptoms
The safety and efficacy of lofexidine was examined within the first 7 days of withdrawal from short-acting opioids.
NEW YORK — Lofexidine (LFX) safely facilitates opioid discontinuation at 3.2 and 2.4 mg/day doses, per data from a pooled analysis presented at the 2018 American Psychiatric Association (APA) Annual Meeting, held May 5-9 in New York City.
Investigators extracted data from 2 phase 3 placebo-controlled studies that evaluated withdrawal symptoms during the first 7 days of withdrawal from short-acting opioids (heroin or opioid analgesics) in opioid-dependent adults.
In the pooled cohort, 586 participants were randomly assigned to receive LFX and 281 received placebo. In the first study, subjects were randomly assigned to receive placebo or LFX 3.2 mg/day for 5 days; in the second, subjects were randomly assigned to receive placebo, LFX 3.2 mg/day, or LFX 2.4 mg/day for 7 days. The severity of withdrawal symptoms was assessed per the Short Opiate Withdrawal Scale-Gossop (SOWS-G).
Of the total population, 242 participants in the LFX group (41.3%) and 77 participants in the placebo group (27.4%) completed the treatment course, and participants in the LFX group remained in the trial longer than their counterparts. Peak SOWS-G scores for Days 1 to 5 were lower in both LFX dose groups compared with placebo (P <.05), indicating greater reduction of withdrawal symptoms with LFX.
Differences in SOWS-G mean scores between the LFX and placebo groups were clinically important. Additional end points, including scores on the Objective Opioid Withdrawal Scale and the Clinical Opioid Withdrawal Scale, also trended in favor of LFX efficacy.
Of patients who discontinued treatment, the most frequently reported reasons were consent withdrawn (LFX, 29.0%; placebo, 32.4%) and lack of efficacy (LFX, 15.7%; placebo, 31.7%). Most adverse events reported were mild or moderate in severity, though patients in the LFX group experienced a higher rate of hypotension, orthostatic hypotension, bradycardia, dizziness, somnolence, dry mouth, and sedation.
Serious adverse events were low, occurring in just 2.3% of the LFX group and 3.2% of the placebo group. LFX was associated with clinically insignificant transient prolongation of the QTc interval on electrocardiogram. These results suggest that LFX is safely administered at both the 2.4 mg and 3.2 mg/day doses, and is effective in reducing withdrawal symptoms. Such data may be helpful for clinicians in developing treatment courses for patients who are exhibiting withdrawal symptoms from short-acting opioids.
Tirado CF, Pirner M, Clinch T, Gorodetzky C. Lofexidine efficacy and safety in opioid withdrawal: pooled analysis of phase 3 studies. Presented at: 2018 American Psychiatric Association (APA) Annual Meeting; New York, NY; May 5-9. Poster 110.