Pharmacotherapy for ADHD

Stimulant selection often starts with short- or intermediate-acting methylphenidate or amphetamine formulations based on individual tolerability. Metabolism considerations include CYP2D6 genotype for d-methylphenidate clearance and CYP3A4 activity for amphetamines—poor metabolizers may require lower doses or alternative agents. Patients with anxiety disorders often tolerate methylphenidate better than amphetamines, while those with substance use history may benefit from longer-acting or non-oral formulations. Initial dosing should always begin low and titrate slowly under clinical supervision.

Tapering strategies depend on reason for discontinuation: abrupt cessation of stimulants can trigger rebound fatigue, irritability, or depressive symptoms. For adverse effects like appetite suppression or insomnia, a gradual reduction over 1–2 weeks allows body systems to recalibrate. In non-responders, a full trial must include adequate dose escalation—typically 4–6 weeks per dose—before switching. When transitioning between formulations, overlap coverage briefly to avoid symptom gaps, especially in occupational or academic settings where function is time-sensitive.

Non-response criteria include insufficient symptom improvement after max-tolerated dose for 4–6 weeks, or persistent intolerable side effects despite dose adjustments. Before discontinuation, assess adherence, correct diagnosis, and comorbid contributions. Alternative pharmacotherapies like atomoxetine, guanfacine, or bupropion may be considered, especially in cases of tics, anxiety, or bipolar comorbidity where stimulants carry higher risk. Always document rationale for regimen changes in the clinical record.