Can energy drinks reduce the depressor effect of ethanol? An experimental study in mice Sionaldo E. Ferreira 1 , Isabel M. Hartmann Quadros 1 ,A ´ gatha A. Trindade 2 , Shirley Takahashi 2 , Renata G. Koyama 2 , Maria Lucia O. Souza-Formigoni 3, * Department of Psychobiology, Federal University of Sa ˜o Paulo, UNIFESP, Rua Botucatu no. 862 1o Andar, Vila Clementino, Sa ˜ o Paulo, SP 04023-062, Brazil Received 7 October 2003; received in revised form 8 May 2004; accepted 29 June 2004 Abstract Although the popularization of the combined use of alcoholic beverages and energy drinks (ED) containing caffeine, taurine and other substances has increased, there are no controlled experimental studies on the effects of ED alone or combined with ethanol. This work aimed at evaluating the effects of different doses of ED combined or not with ethanol, on the locomotor activity of Swiss mice. The administration of 3.57, 10.71 or 17.86 ml/kg of ED alone increased the locomotor activity of the animals in relation to a control group. Low doses of ethanol (0.5, 1.0 and 1.5 g/kg) alone or in combination with 10.71 ml/kg of ED did not affect their locomotor activity. However, the reduction of activity observed after 2.5 g/kg of ethanol was antagonized by 10.71 ml/kg of ED. Further studies on the mechanisms of this interaction are still needed. D 2004 Elsevier Inc. All rights reserved. Keywords: Ethanol; Energy drink; Taurine; Caffeine; Locomotor activity 1. Introduction We could observe a fast popularization of the combined use of alcoholic beverages and energy drinks in recent years. Most of the beverages known as benergy drinksQ consist of a combination of carbohydrates (about 11 g/dl), taurine (about 400 mg/dl), caffeine (about 32 mg/dl), gluconolactone (about 240 mg/dl) and vitamins of the B complex. There are few studies on this issue on the effects of these beverages in the literature. Some studies reported enhance- ment of the mood state, as well as physical and psychomotor performance (time of motor reaction, concentration, work memory and subjective sensation of alertness and vigor), after the ingestion of Red Bull [1,2]. Popular reports suggest that energy drinks could reduce the intensity of the depressant effects of ethanol. In a survey carried out in Brazil with 136 users of energy drinks, the main reason reported by them to use energy drinks combined with alcoholic beverages was the reduction of sleepiness and the increase of the sensation of pleasure after its ingestion [3]. Riesselman et al. [4] suggested that the associated use of alcoholic beverages and energy drinks might have reduced the perception of two youngsters regarding the intensity of their alcohol intoxication, thus causing an automobile accident. Ferreira et al. [5], in a study carried out with volunteers, reported that the ingestion of 3.57 ml/kg of energy drink yielded little effect in antagonizing the symptoms of intoxication caused by the ingestion of 0.6 or 1.0 g/kg of ethanol. The performance in a maximal effort test observed after alcohol combined with energy drink ingestion was similar to that observed after alcohol only. No significant differences were detected on blood alcohol 0031-9384/$ - see front matter D 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.physbeh.2004.06.017 * Corresponding author. Tel.: +55-11-5539-0155; fax: +55-11-5572- 5092. E-mail address: mlformig@psicobio.epm.br (M.L.O. Souza-Formigoni). 1 Postgraduate student of Psychobiology at the Federal University of Sa ˜o Paulo (UNIFESP), FAPESP fellowship. 2 Scientific Initiation Student in the Department of Psychobiology at UNIFESP. 3 Full Professor at the Department of Psychobiology at UNIFESP. Physiology & Behavior 82 (2004) 841 – 847