'Candyflipping': synergistic discriminative effect of LSD and MDMA.

The co-administration of D-lysergic acid diethylamide (LSD; 'Acid') and 3,4-methylenedioxymethamphetamine (MDMA; 'Ecstasy'; 'XTC'), has reached a prevalence that has allowed for the street terminology 'candyflipping' to describe the combination. Internet sites indicate a significant enhancement of central effects with their simultaneous use. In this preliminary observation, male Fawn-Hooded rats were trained to discriminate 1.5 mg/kg MDMA and were, subsequently, tested with doses of MDMA (0.15 mg/kg) or LSD (0.04 mg/kg) that each produced a saline-like response. Co-administration of these doses of MDMA and LSD synergized to produce a maximal MDMA-like response. The possible mechanism for synergistic action upon central serotonergic neurons is discussed to explain the observed effect.