amphetamines

Amphetamines are a class of potent central nervous system stimulants based on the phenethylamine structure. They include compounds such as dextroamphetamine, methamphetamine, and the mixed amphetamine salts used in prescription products (for example, Adderall) as well as lisdexamfetamine (Vyvanse). Because of their potential for abuse and health risks, they are controlled substances in many countries.

Mechanistically, amphetamines act as indirect sympathomimetics. They enter neurons and promote the release of monoamines—dopamine, norepinephrine, and, to a lesser extent, serotonin—while also inhibiting their reuptake. They accomplish this by reversing transporters (DAT, NET, SERT) and by promoting vesicular release through VMAT2. Methamphetamine is more lipophilic and crosses the blood–brain barrier more readily, often producing more intense and longer-lasting effects and greater neurotoxicity than other forms.

Medical use is primarily for attention-deficit/hyperactivity disorder (ADHD) and narcolepsy. Prescriptions include mixed amphetamine salts, dextroamphetamine, and lisdexamfetamine. They can be effective for improving focus, impulse control, and daytime alertness when used under medical supervision. They are occasionally used off-label in other contexts, though safety concerns limit such use.

Risks include insomnia, reduced appetite, increased heart rate and blood pressure, anxiety, and potential for tolerance, dependence, and withdrawal. Chronic high-dose use can lead to psychosis, mood disturbances, and cardiovascular complications. Overdose may cause agitation, hyperthermia, seizures, or coma. Global regulation and monitoring aim to balance therapeutic benefits with the potential for abuse and harm.