Is methamphetamine classified as a stimulant, an amphetamine, or both?

Methamphetamine Classification

Methamphetamine is both a stimulant and an amphetamine—these classifications are not mutually exclusive but rather describe the drug from different perspectives. 1

Chemical and Pharmacological Classification

Methamphetamine is chemically classified as a member of the amphetamine group of sympathomimetic amines, with the formal chemical name (αS)-α-Methylbenzeneethan-(N-methyl)-amine Hydrochloride. 1 It is specifically a derivative of amphetamine, distinguished by an additional methyl group on the nitrogen atom. 2

From a pharmacological mechanism standpoint, methamphetamine functions as a sympathomimetic amine with central nervous system (CNS) stimulant activity. 1 This means it stimulates the sympathetic nervous system and produces stimulant effects on the brain and body.

Functional Classification as a Stimulant

Methamphetamine is definitively a CNS stimulant, producing characteristic stimulant effects including:

• Elevation of systolic and diastolic blood pressures 1
• Increased alertness, mood elevation, and energy levels in the short term 3
• Enhanced concentration and wakefulness 3
• Increased extracellular monoamines such as dopamine and norepinephrine 4

The drug exerts its stimulant effects through multiple mechanisms, including direct agonist activity at adrenergic receptors and indirect release of dopamine and norepinephrine from presynaptic terminals. 5

Relationship to Amphetamine Class

Methamphetamine belongs to the amphetamine class of drugs, sharing structural and pharmacological similarities with amphetamine itself. 6, 1 Both drugs are exogenous agonists at trace amine receptors and produce similar sympathomimetic effects. 6

However, methamphetamine exhibits some distinct neurochemical differences from amphetamine, despite their close relationship:

• In the nucleus accumbens, amphetamine raises glutamate levels while methamphetamine does not 7
• In the prefrontal cortex, methamphetamine raises glutamate levels while amphetamine does not 7
• Methamphetamine may be less effective than amphetamine at raising dopamine levels in the prefrontal cortex 7

The characterization of methamphetamine as universally "more potent" than amphetamine is not consistently supported, as equipotency has been demonstrated at low, behaviorally activating doses under many conditions. 8

Clinical and Historical Context

Methamphetamine was historically used as a prescription medication, reaching widespread medical use in the 1950s and 1960s for conditions including depression and obesity, with amphetamine prescriptions peaking at 31 million in the United States in 1967. 2 This medical use classified it alongside other therapeutic amphetamines and stimulants.

Currently, methamphetamine is primarily used recreationally rather than medically, though it remains FDA-approved in 5 mg oral tablets for specific indications. 1 Its classification as both an amphetamine derivative and a CNS stimulant remains accurate regardless of its current predominant illicit use. 2, 3

Practical Clinical Implications

When discussing methamphetamine in clinical contexts, both terms are appropriate and accurate:

• Use "amphetamine" when emphasizing its chemical class, structural relationship to other amphetamines, or discussing amphetamine-class drug interactions 6
• Use "stimulant" when emphasizing its pharmacological effects, mechanism of action, or clinical manifestations 1, 3, 4
• Use both terms when comprehensive classification is needed, as the drug simultaneously belongs to both categories 1

In guideline documents and clinical practice, methamphetamine is consistently grouped with amphetamines when discussing cardiovascular effects, monitoring requirements, and contraindications, reflecting its membership in the amphetamine class. 5 Simultaneously, it is classified with other CNS stimulants when discussing mechanism of action and acute effects. 1, 4