PMA has been associated with numerous adverse reactions including death. Effects of PMA ingestion include many effects of the hallucinogenic amphetamines including accelerated and irregular heartbeat, blurred vision, and a strong feeling of intoxication that is often unpleasant. While PMA can reportedly be euphoric at low doses, the dose-response curve is much steeper than that of MDMA, and at higher doses unpleasant effects such as nausea and vomiting, severe hyperthermia and hallucinations quickly overpower any pleasurable effects.

The effects of PMA also seem to be much more unpredictable and variable between individuals than those of MDMA, and sensitive individuals may die from a dose of PMA that a less susceptible person might only be mildly affected by. There are approximately twice as many deaths caused by PMA as by MDMA, even though the actual proportion of PMA on the market is only a fraction of that of MDMA. While PMA alone may cause significant toxicity, the combination of PMA with MDMA has a synergistic effect that seems to be particularly hazardous.

Since PMA has a slow onset of effects, several deaths have occurred where individuals have taken a pill containing PMA, followed by a pill containing MDMA some time afterwards due to thinking that the first pill was not active.