Methiopropamine (MPA)
Methiopropamine (MPA) is a thiophene-ring analogue of methamphetamine sold as a research-chemical stimulant, particularly popular in the UK after mephedrone was banned. It is a norepinephrine-dopamine reuptake inhibitor with milder subjective effects than methamphetamine, but has been implicated in fatalities and has very limited human characterisation.
01 Overview
Methiopropamine was first synthesised in 1942 and re-emerged around 2010 as a legal-high stimulant, marketed under names like 'NRG-3'. Replacing the benzene ring of methamphetamine with a thiophene gives a shorter-acting, somewhat less potent stimulant.
Human data is limited to case reports and forensic toxicology, including several deaths where MPA was present, often alongside other drugs. No controlled pharmacokinetic studies exist. It was brought under UK temporary control in 2015.
02 Mechanism
Acts primarily as a norepinephrine and dopamine reuptake inhibitor with weaker serotonergic activity; thiophene bioisostere of methamphetamine.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Common (approximate, anecdotal) | 10–40 mg | Insufflated | Faster, harsher onset; higher compulsion risk. |
| Common (approximate, anecdotal) | 20–60 mg | Oral | User-reported; not clinically validated. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Mild-moderate stimulationWakefulness, focus and mild euphoria described as less intense than methamphetamine. | Moderate | Anecdotal | |
| Appetite suppressionReduced appetite typical of sympathomimetic stimulants. | Moderate | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Tachycardia and hypertensionRaised heart rate and blood pressure commonly reported. | Moderate | Common | Anecdotal | |
| Anxiety and insomniaRestlessness, anxiety and prolonged sleeplessness after use. | Moderate | Common | Anecdotal |