## First-Line Pharmacotherapy for ADHD Symptoms in ASD **Key Point:** Methylphenidate is the first-line psychostimulant for attention-deficit/hyperactivity symptoms in children with autism spectrum disorder, particularly when ADHD features are prominent. ### Mechanism of Action Methylphenidate is a sympathomimetic amine that blocks the reuptake of dopamine and noradrenaline at the presynaptic terminal, increasing their availability in the prefrontal cortex and striatum. This enhances executive function, attention, and impulse control. ### Evidence in ASD + ADHD - Stimulants (methylphenidate, amphetamines) show efficacy in 50–70% of children with ASD who have comorbid ADHD symptoms - Response rates are comparable to non-ASD children, though some children with ASD may show increased irritability or stereotypies at higher doses - Typically started at low doses (5 mg once or twice daily) with gradual titration **High-Yield:** Methylphenidate is preferred over amphetamines in ASD because it has a lower risk of exacerbating stereotyped behaviours and tics. ### Dosing Considerations - Immediate-release: 5–20 mg once or twice daily - Extended-release formulations available for improved compliance - Monitor for appetite suppression, sleep disturbance, and increased anxiety **Clinical Pearl:** Always screen for comorbid anxiety, tics, and cardiac history before starting stimulants. Children with ASD may have higher rates of sensory sensitivities and anxiety that could be worsened by stimulants. ### Contraindications & Cautions - Avoid if active tics or Tourette syndrome present - Use caution in children with significant anxiety or seizure history - Monitor blood pressure and heart rate regularly [cite:DSM-5 p 53–54; American Academy of Pediatrics Guidelines on ADHD]
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