Objectives: To describe the epidemiology and toxicity of caffeinated energy drink exposures in Australia. Design, setting and subjects: Retrospective observational study analysing data from calls regarding energy drink exposures recorded in the database of an Australian poisons information centre over 7 years to 2010. Main outcome measures: Type of exposure; co‐ingestants; symptoms reported; and reported hospitalisations. Results: Callers reported 297 exposures to energy drinks, which showed an increasing annual trend from 12 in 2004 to 65 in 2010. Median age for the 217 subjects with recreational exposure was 17 years (interquartile ratio [IQR], 15–21; range, 11–60) and 57% were male. One hundred recreational users co‐ingested other substances, predominantly alcohol (50) or other caffeinated products (44). The number of energy drinks consumed in one session varied greatly (median, 5 units; IQR, 3–8; range, 1–80). Most subjects who reported recreational use reported experiencing symptoms (87%). The most common symptoms were palpitations, agitation, tremor and gastrointestinal upset. Twenty‐one subjects had signs of serious cardiac or neurological toxicity, including hallucinations, seizures, arrhythmias or cardiac ischaemia. At least 128 subjects (57 with no co‐ingestants) required hospitalisation. Conclusions: Reports of caffeine toxicity from energy drink consumption are increasing, particularly among adolescents, warranting review and regulation of the labelling and sale of these drinks. Educating adolescents and increasing the community's awareness of the hazards from energy drinks is of paramount importance.

Despite their improved pharmacokinetic profile, the Z-drugs, zolpidem, zopiclone, and zaleplon, have a spectrum of adverse effects comparable to benzodiazepines. This review focuses on the impairment from Z-drugs on cognition, behavior, psychomotor performance, and driving ability. Z-drugs are short-acting GABA agonists that reduce sleep latency without disturbing sleep architecture. Bizarre behavioral effects have prompted warnings on the prescription, dispensation, and use of Z-drugs. Psychomotor impairment, falls, and hip fractures are more likely to occur with Z-drugs that have longer half-lives, that are taken at higher-than-recommended doses and when mixed with other psychoactive substances including alcohol. Zopiclone and higher doses of zolpidem are more likely to cause anterograde amnesia than zaleplon. Z-drugs, especially zolpidem, are associated with complex behaviors such as sleepwalking, sleep-driving, and hallucinations. Patients taking zopiclone and zolpidem have an increased risk of motor vehicle collisions, over double that of unexposed drivers. Driving impairment occurs with zopiclone and higher doses of zolpidem but is unlikely to occur after 4 h post-zaleplon administration. The residual effect of Z-drugs on next-day cognitive and psychomotor performance has significant impact on lifestyle, safety, and occupational considerations, including motor vehicle and machine operation. The risk-benefit analysis of Z-drugs in the treatment of insomnia, particularly in the elderly, may not favor treatment due to the increased risks of falls and motor vehicle collisions. Prescribers should warn patients taking Z-drugs of minimum time thresholds before they operate machinery or drive motor vehicles.

The Z-drugs zolpidem, zopiclone, and zaleplon were hailed as the innovative hypnotics of the new millennium, an improvement to traditional benzodiazepines in the management of insomnia. Increasing reports of adverse events including bizarre behavior and falls in the elderly have prompted calls for caution and regulation. Z-drugs have significant hypnotic effects by reducing sleep latency and improving sleep quality, though duration of sleep may not be significantly increased. Z-drugs exert their effects through increased γ-aminobutyric acid (GABA) transmission at the same GABA-type A receptor as benzodiazepines. Their pharmacokinetics approach those of the ideal hypnotic with rapid onset within 30 min and short half-life (1-7 h). Zopiclone with the longest duration of action has the greatest residual effect, similar to short-acting benzodiazepines. Neuropsychiatric adverse events have been reported with zolpidem including hallucinations, amnesia, and parasomnia. Poisoning with Z-drugs involves predominantly sedation and coma with supportive management being adequate in the majority. Flumazenil has been reported to reverse sedation from all three Z-drugs. Deaths from Z-drugs are rare and more likely to occur with polydrug overdose. Zdrugs can be detected in blood, urine, oral fluid, and postmortem specimens, predominantly with liquid chromatography-mass spectrometry techniques. Zolpidem and zaleplon exhibit significant postmortem redistribution. Zaleplon with its ultra-short half-life has been detected in few clinical or forensic cases possibly due to assay unavailability, low frequency of use, and short window of detection. Though Z-drugs have improved pharmacokinetic profiles, their adverse effects, neuropsychiatric sequelae, and incidence of poisoning and death may prove to be similar to older hypnotics.