nonstimulant

Nonstimulant is a term used in medicine to describe drugs that do not have the classical stimulant effects on the central nervous system. In psychiatry, nonstimulants are most often discussed as alternatives to stimulant medications for attention-deficit/hyperactivity disorder (ADHD). They may be chosen when stimulants are ineffective, poorly tolerated, contraindicated, or when there is a concern about misuse.

Common nonstimulants for ADHD include atomoxetine, guanfacine extended-release, clonidine extended-release, and viloxazine extended-release (brand name Qelbree). Bupropion is sometimes used off-label in adults. Atomoxetine is a selective norepinephrine reuptake inhibitor; guanfacine and clonidine are alpha-2 adrenergic agonists; viloxazine is a norepinephrine reuptake inhibitor with additional mechanisms. Bupropion inhibits norepinephrine and dopamine reuptake. These agents have different pharmacologic profiles and may affect attention, impulse control, and hyperactivity through distinct pathways.

Onset of effect for nonstimulants is typically slower than that of stimulant medications, often taking several weeks to reach full benefit. Efficacy can be modest and varies among individuals; nonstimulants are commonly used as second-line therapy or as adjuncts to stimulants. They may be preferred when there is a risk of substance misuse, comorbid conditions, or problematic stimulant-related side effects.

Safety and monitoring requirements vary by drug. Common side effects include stomach upset, sleep disturbance, and changes in blood pressure or heart rate (atomoxetine); drowsiness and sedation (guanfacine, clonidine); and rare liver-related concerns with atomoxetine. Regular follow-up is recommended to assess efficacy and safety.