Effects of Mixing Energy Drinks With Alcohol on Driving-Related Skills.

BACKGROUND: Energy drinks (EDs) reduce sleepiness and fatigue and improve driving performance whereas alcohol does just the opposite. Although it is a trendy combination among young people, the effects of alcohol mixed with EDs on driving performance have been poorly studied. The aim was to assess if there is an interaction between the effects of both drinks on driving-related skills as well as perceptions about driving ability. METHODS: We conducted a randomized, double-blind, and placebo-controlled 4-way crossover clinical trial. Participants were 16 healthy volunteers. Interventions of 60 g of ethanol and 750 mL of Red Bull (RB) were administered in 2 separated doses. Conditions were alcohol + RB placebo, alcohol + RB, alcohol placebo + RB, and both placebos. Objective performance was assessed using a tracking test and simple reaction time, N-Back, and movement estimation tasks. Additionally, willingness to drive, other subjective effects, and ethanol and caffeine blood concentrations were also measured. RESULTS: Alcohol increased the time outside the road in the tracking test and increased simple reaction time, but the addition of RB had no main or interaction effects on performance. Nonetheless, driving-related skills after alcohol + RB were better than after alcohol alone. Willingness to drive increased with the combination of drinks. RB also reduced alcohol-induced sedation whereas drunkenness did not change. These effects were seen even though alcohol + RB increased alcohol (14.8%) and caffeine plasma concentrations (17.6%). CONCLUSIONS: Mixing EDs with alcohol predisposes consumers to drive under alcohol influence, perhaps in part because EDs counteract its detrimental effects on driving-related skills. Clinicaltrials.gov: NCT02771587.

Human Pharmacology of Mephedrone in Comparison with MDMA.

Mephedrone (4-methylmethcathinone) is a novel psychoactive substance popular among drug users because it displays similar effects to MDMA (3,4-methylenedioxymethamphetamine, ecstasy). Mephedrone consumption has been associated with undesirable effects and fatal intoxications. At present, there is no research available on its pharmacological effects in humans under controlled and experimental administration. This study aims to evaluate the clinical pharmacology of mephedrone and its relative abuse liability compared with MDMA. Twelve male volunteers participated in a randomized, double-blind, crossover, and placebo-controlled trial. The single oral dose conditions were: mephedrone 200 mg, MDMA 100 mg, and placebo. Outcome variables included physiological, subjective, and psychomotor effects, and pharmacokinetic parameters. The protocol was registered in ClinicalTrials.gov (NCT02232789). Mephedrone produced a significant increase in systolic and diastolic blood pressure, heart rate, and pupillary diameter. It elicited stimulant-like effects, euphoria, and well-being, and induced mild changes in perceptions with similar ratings to those observed after MDMA administration although effects peaked earlier and were shorter in duration. Maximal plasma concentration values for mephedrone and MDMA peaked at 1.25 h and 2.00 h, respectively. The elimination half-life for mephedrone was 2.15 h and 7.89 h for MDMA. In a similar manner to MDMA, mephedrone exhibits high abuse liability. Its earlier onset and shorter duration of effects, probably related to its short elimination half-life, could explain a more compulsive pattern of use as described by the users.