Pharmacologic management of autism spectrum disorder: A review of 7 studies

7. Wink LK, Adams R, Horn PS, et al. A randomized placebo-controlled cross-over pilot study of riluzole for drug-refractory irritability in autism spectrum disorder. J Autism Dev Disord. 2018;48(9):3051-3060.

Glutamatergic dysregulation has been identified as a potential cause of ASD. Riluzole, a glutamatergic modulator that is FDA-approved for treating amyotrophic lateral sclerosis, is a drug of interest for the treatment of ASD-related irritability due to this proposed mechanism. Wink et al¹⁰ evaluated riluzole for irritability in patients with ASD.

Study design

• This randomized, double-blind, placebo-controlled, crossover pilot study evaluated the tolerability and safety of adjunctive riluzole treatment for drug-refractory irritability in 8 patients with ASD.
• Participants were age 12 to 25 years, had a diagnosis of ASD confirmed by the autism diagnostic observation schedule 2, and an ABC-I subscale score ≥18. Participants receiving ≥2 psychotropic medications or glutamatergic/GABA-modulating medications were excluded.
• Participants received either 5 weeks of riluzole followed by 5 weeks of placebo, or vice versa; both groups then had a 2-week washout period.
• Riluzole was started at 50 mg/d, and then increased in 50 mg/d–increments to a maximum of 200 mg/d by Week 4.
• Primary outcome measures were change in score on the ABC-I and CGI-I.

Outcomes

• No significant treatment effects were identified.
• All participants tolerated riluzole, 200 mg/d, but increased dosages did not result in a higher overall treatment effect.
• There were no clinically significant adverse effects or laboratory abnormalities.

Conclusion

• Riluzole, 200 mg/d, was well tolerated but had no significant effect on irritability in adolescents with ASD.