The acute cardiovascular effects of 3,4-methylenedioxymethamphetamine (MDMA) and p-methoxyamphetamine (PMA)

Abstract

A number of reports of severe acute toxicity as a result of recreational ingestion of what was believed to be 3,4-methylenedioxymethamphetamine (MDMA) (ecstasy) have revealed, on chemical analysis of the victim's blood, to be due to p-methoxyamphetamine (PMA). Increased blood pressure and heart rate have been associated with this toxicity, which is exacerbated by high ambient temperature. We compared MDMA and PMA effects on blood pressure and heart rate in conscious freely moving rats at ambient temperatures of 20°C and 30°C. Drugs were administered at 5, 10, 15 and 20 mg/kg s.c. and cardiovascular recordings continued 2-4 hours post-drug. At 20°C MDMA had a slight lowering effect on blood pressure or heart rate at all doses tested. In contrast, PMA administered at the same ambient temperature caused a dose-dependent long-lasting bradycardia and lowering of blood pressure. At 30°C MDMA caused a slight increase in heart rate and a moderate rise in blood pressure. PMA did not significantly change heart rate or blood pressure at any of the doses tested. ECG was only influenced at the highest dose (20 mg/kg) of PMA and MDMA administered at 30°C where ST elongation was observed. These data indicate that although these drugs are considered similar in their psychotrophic effects they have different actions on the cardiovascular system of the rat. These findings may have implications in the diagnosis and emergency treatment of victims of MDMA/PMA toxicity.