Methamphetamine (metamfetamine)

Drugs of abuse
Drugs of abuse

A potent synthetic stimulant with high addiction potential. A prescription form exists for ADHD in some countries; illicit «crystal» drives overdoses.

Updated Nov 1, 2026

Also called: Metamfetamine, Crystal, Meth

Quick facts

Group: Drugs of abuse
Target: Dopamine and noradrenaline transporters (DAT, NET) and VMAT2; also the receptor TAAR1
Used for: Clinical relevance
Key effects: Insomnia · Tachycardia · Anxiety
Monitor: Heart rate · Creatine kinase · On prescription
ATC: N06BA03

No doses: the clinician sets them by the current guideline.

Mechanism of action

Dopamine and noradrenaline transporters (DAT, NET) and VMAT2; also the receptor TAAR1Methamphetamine (metamfetamine)

The figure shows methamphetamine bound to the human trace amine-associated receptor 1 (TAAR1), which it activates; no human transporter structure with methamphetamine is available.

Target in 3D: Dopamine and noradrenaline transporters (DAT, NET) and VMAT2; also the receptor TAAR1. PDB structure 9JKQ (RCSB PDB, public domain). View the structure at RCSB PDB

Methamphetamine enters nerve terminals through the dopamine and noradrenaline transporters, empties the storage vesicles and makes the transporters run in reverse, releasing large amounts of dopamine and noradrenaline (and some serotonin); it also blocks their reuptake. It reaches the brain fast, especially when smoked or injected, which gives an intense rush and strong reinforcement. The noradrenaline surge produces the sympathomimetic toxidrome.

Methamphetamine enters through DAT and NET
It empties vesicles and reverses the transporters
Dopamine and noradrenaline flood the synapse
Euphoria and alertness; tachycardia, hypertension, hyperthermia

Indications

Attention deficit hyperactivity disorder in children (prescription product approved in the United States) Attention-deficit/hyperactivity disorder (ADHD) →
Clinical relevance: methamphetamine intoxication and stimulant use disorder Stimulant use disorder (cocaine, amphetamines) →

Adverse effects

Common

Insomnia, anorexia and weight loss
Tachycardia, palpitations and hypertension
Anxiety, irritability and paranoia
Dry mouth and tooth decay («meth mouth») with chronic use

Contraindications

Use of an MAOI now or within the previous two weeks (hypertensive crisis)
Hypersensitivity to amphetamines
Avoided in serious structural heart disease

Key interactions

MAOIs: Hypertensive crisis; contraindicated
SSRIs, SNRIs, triptans and other serotonergic drugs; CYP2D6 inhibitors: Serotonin syndrome risk
Urinary alkalinisers (for example sodium bicarbonate) or acidifiers: Alkalinisers raise and prolong methamphetamine levels; acidifiers lower them
Opioids such as fentanyl in the illicit supply: Mixed overdoses with respiratory depression

What is monitored

Heart rate, blood pressure, temperature and ECG
Creatine kinase, potassium, kidney function and troponin when there is chest pain
Psychiatric state and suicide risk, also during withdrawal
On prescription: growth, blood pressure and signs of misuse

Administration and safety

Prescription tablets are a high-abuse controlled medicine, kept under strict storage and record keeping
Illicit methamphetamine is smoked, snorted, injected or swallowed; injection adds infection risk
Street products may contain opioids such as fentanyl

Pregnancy and breastfeeding

Linked to placental abruption, preterm birth, low birth weight and withdrawal in the newborn; stopping at any point in pregnancy improves outcomes.

Nursing care

Keep the patient in a calm space and protect from injury during agitation
Monitor temperature and cardiac rhythm continuously in severe intoxication
Expect a crash with deep sleep, hunger and low mood after a binge; assess suicide risk
Check skin, teeth and injection sites; screen for HIV and hepatitis when appropriate
Link to behavioural treatment; contingency management is the best-studied option

Pharmacokinetics

Absorption: Absorbed by mouth, through the nasal mucosa and the lungs; also injected
Distribution: Lipid-soluble: crosses the blood–brain barrier and the placenta easily
Metabolism: Liver (hydroxylation, N-demethylation, deamination)
Elimination: Kidneys, largely unchanged; acidic urine speeds and alkaline urine slows its excretion
Half-life: Several hours, longer when the urine is alkaline

Test yourself

Think of the answer, then tap the question to see it.

How does methamphetamine raise synaptic dopamine?

It enters through DAT, empties vesicles via VMAT2 and reverses the transporter so dopamine is released; it also blocks reuptake.

How does urine pH change methamphetamine elimination?

Acidic urine speeds its renal excretion; alkaline urine slows it and prolongs the effect.

Is there an approved medicine for methamphetamine use disorder?

No; behavioural treatments such as contingency management and cognitive behavioural therapy are the mainstay.

Which drug is first line for methamphetamine-induced agitation in the Colombian toxicology guide?

A benzodiazepine; antipsychotics such as haloperidol or olanzapine are options if needed.

Add to my cards (4)

Connections

← Back to the class: Drugs of abuse

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: DailyMed - METHAMPHETAMINE HYDROCHLORIDE tablet (DailyMed (U.S. National Library of Medicine), 2026); Methamphetamine (National Institute on Drug Abuse (NIDA), 2026); Guía para el Manejo de Emergencias Toxicológicas (Ministerio de Salud y Protección Social; Organización Panamericana de la Salud, 2017); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.