Amantadine for Autism Spectrum Disorder and Irritability
Direct Answer
Amantadine is not recommended for treating autism spectrum disorder or irritability, as there is no evidence supporting its use for these conditions, and established guidelines do not include it in treatment algorithms for ASD. 1
Evidence-Based Treatment for Irritability in ASD
The provided evidence contains no data on amantadine for autism or irritability. Current treatment guidelines are clear about what medications are effective:
FDA-Approved First-Line Agents for Irritability
Risperidone (0.5-3.5 mg/day) and aripiprazole (5-15 mg/day) are the only FDA-approved medications for irritability in ASD and should be used as first-line pharmacotherapy when medication is indicated. 1
- Both medications show significant improvement on the Aberrant Behavior Checklist Irritability subscale compared to placebo 1
- Risperidone demonstrates efficacy in multiple large RCTs with effects typically starting within 2 weeks 2
- Aripiprazole has comparable efficacy and safety to risperidone (mean effective dose 5.5 mg/day vs 1.12 mg/day for risperidone) 3
Critical Prescribing Considerations
Medication should only be prescribed after nonpharmacological interventions have been attempted, as risperidone and aripiprazole carry significant metabolic side effects including weight gain, increased prolactin, and metabolic syndrome. 2, 4
- Combining medication with parent training is moderately more efficacious than medication alone for decreasing serious behavioral disturbance 1
- Regular monitoring for metabolic effects is essential but often underemphasized 4
- Periodic reassessment to determine if ongoing treatment is needed is mandatory 4
Why Amantadine Is Not Appropriate
Amantadine is an antiviral and antiparkinsonian medication with significant CNS side effects including nervousness, anxiety, insomnia, difficulty concentrating, and lightheadedness occurring in approximately 13% of users. 2
- More serious side effects include marked behavioral changes, delirium, hallucinations, agitation, and seizures, particularly in vulnerable populations 2
- These adverse effects would be particularly problematic in individuals with ASD who already experience behavioral dysregulation
- No evidence exists in the literature for amantadine's efficacy in treating core or associated symptoms of ASD 1, 5, 6
Alternative Medication Options When First-Line Agents Fail
If risperidone or aripiprazole are ineffective or not tolerated:
- For ADHD-type symptoms with impulsivity: Methylphenidate (0.3-0.6 mg/kg/dose, 2-3 times daily) shows efficacy in 49% of children with ASD versus 15.5% on placebo 1, 7
- For treatment-resistant hyperactivity: Alpha-2 agonists (clonidine or guanfacine) can be considered, though evidence is limited 2, 7
- Avoid benzodiazepines due to risk of behavioral disinhibition, which can paradoxically worsen irritability 7