Glial Attenuation With Ibudilast in the Treatment of Medication Overuse Headache: A Double-Blind, Randomized, Placebo-Controlled Pilot Trial of Efficacy and Safety.

BACKGROUND: Medication overuse headache (MOH) is a condition bordering between a chronic pain condition and a substance dependence disorder. Activation of immunocompetent glial cells in the central nervous system has been linked to both pathological pain and drug addiction/reward. Preclinically, ibudilast attenuates glial activation and is able to reduce neuropathic pain and markers of substance dependence. We therefore hypothesized ibudilast would reduce headache burden and opioid analgesic requirements in patients with opioid overuse headache. OBJECTIVE: To determine if treatment with ibudilast provides a greater reduction in headache index than placebo in MOH patients consuming opioids. METHODS: Participants with MOH who were using opioids were randomized via computer-generated code to ibudilast 40 mg or placebo twice daily for 8 weeks in a double-blind, parallel groups study. Before randomization participants completed a 4-week baseline headache diary. During treatment, headache diary data collection continued and participants attended 4 study visits during which quantitative sensory testing was performed. Blood samples for immune biomarker analyses were collected before and after treatment in a subgroup of participants. RESULTS: Thirty-four participants were randomized, 13 of 15 randomized to ibudilast and 17 of 19 randomized to placebo completed treatment. Ibudilast was generally well-tolerated with mild, transient nausea reported as the most common adverse event (66.7% vs 10.5% in placebo group). Results are shown as mean (SD). At the end of treatment no differences in the primary outcome average daily headache index (placebo 62 [44] vs ibudilast 77 [72] groups, difference -15, CI -65 to 35 h × numerical rating scale), or secondary outcomes headache frequency (placebo 23 [8.1] vs ibudilast 24.5 [6.2], difference -1.5, CI -7.7 to 4.8 days/month) and opioid intake (placebo 20.6 [43] vs ibudilast 19 [24.3], difference 1.6, CI -31.5 to 34.8 mg morphine equivalent) were observed between placebo and ibudilast groups. CONCLUSIONS: Using the current dosing regimen, ibudilast does not improve headache or reduce opioid use in patients with MOH without mandated opioid withdrawal. However, it would be of interest to determine in future trials if ibudilast is able to improve ease of withdrawal during a forced opioid down-titration when incorporated into an MOH detoxification program.

A double-blind, randomized, placebo-controlled pilot trial to determine the efficacy and safety of ibudilast, a potential glial attenuator, in chronic migraine.

BACKGROUND: Chronic migraine (CM) is problematic, and there are few effective treatments. Recently, it has been hypothesized that glial activation may be a contributor to migraine; therefore, this study investigated whether the potential glial inhibitor, ibudilast, could attenuate CM. METHODS: The study was of double-blind, randomized, placebo-controlled, two-period crossover design. Participants were randomized to receive either ibudilast (40 mg twice daily) or placebo treatment for 8 weeks. Subsequently, the participants underwent a 4-week washout period followed by a second 8-week treatment block with the alternative treatment. CM participants completed a headache diary 4 weeks before randomization throughout both treatment periods and 4 weeks after treatment. Questionnaires assessing quality of life and cutaneous allodynia were collected on eight occasions throughout the study. RESULTS: A total of 33 participants were randomized, and 14 participants completed the study. Ibudilast was generally well tolerated with mild, transient adverse events, principally nausea. Eight weeks of ibudilast treatment did not reduce the frequency of moderate to severe headache or of secondary outcome measures such as headache index, intake of symptomatic medications, quality of life or change in cutaneous allodynia. CONCLUSION: Using the current regimen, ibudilast does not improve migraine with CM participants.