Dopamine D1 Receptor-Mediated Intracellular Responses in the Hypothalamus after Co-Administration of Caffeine with MDMA

4,4'-DMAR: chemistry, pharmacology and toxicology of a new synthetic stimulant of abuse

In recent years, the spread of new psychoactive substances has dramatically increased in term of availability of both number of compounds and chemical families. In November 2012, 4,4'-Dimethylaminorex (4,4'-DMAR), a novel synthetic stimulant, was first detected in the Netherlands. Between June 2013 and June 2014, thirty-one deaths associated with the consumption of this new drug have been registered across Europe. In this MiniReview, we have summarized the chemical, pharmacological and toxicological information about this new legal high.

Caffeine provokes adverse interactions with 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') and related psychostimulants: mechanisms and mediators

Concomitant consumption of caffeine with recreational psychostimulant drugs of abuse can provoke severe acute adverse reactions in addition to longer term consequences. The mechanisms by which caffeine increases the toxicity of psychostimulants include changes in body temperature regulation, cardiotoxicity and lowering of the seizure threshold. Caffeine also influences the stimulatory, discriminative and reinforcing effects of psychostimulant drugs. In this review, we consider our current understanding of such caffeine-related drug interactions, placing a particular emphasis on an adverse interaction between caffeine and the substituted amphetamine, 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy'), which has been most recently described and characterized. Co-administration of caffeine profoundly enhances the acute toxicity of MDMA in rats, as manifested by high core body temperature, tachycardia and increased mortality. In addition, co-administration of caffeine enhances the long-term serotonergic neurotoxicity induced by MDMA. Observations to date support an interactive model of drug-induced toxicity comprising MDMA-related enhancement of dopamine release coupled to a caffeine-mediated antagonism of adenosine receptors in addition to inhibition of PDE. These experiments are reviewed together with reports of caffeine-related drug interactions with cocaine, d-amphetamine and ephedrine where similar mechanisms are implicated. Understanding the underlying mechanisms will guide appropriate intervention strategies for the management of severe reactions and potential for increased drug-related toxicity, resulting from concomitant caffeine consumption.