γ-Hydroxybutyric Acid: Pharmacokinetics, Pharmacodynamics, and Toxicology.

Gamma-hydroxybutyrate (GHB) is a short-chain fatty acid present endogenously in the brain and used therapeutically for the treatment of narcolepsy, as sodium oxybate, and for alcohol abuse/withdrawal. GHB is better known however as a drug of abuse and is commonly referred to as the "date-rape drug"; current use in popular culture includes recreational "chemsex," due to its properties of euphoria, loss of inhibition, amnesia, and drowsiness. Due to the steep concentration-effect curve for GHB, overdoses occur commonly and symptoms include sedation, respiratory depression, coma, and death. GHB binds to both GHB and GABAB receptors in the brain, with pharmacological/toxicological effects mainly due to GABAB agonist effects. The pharmacokinetics of GHB are complex and include nonlinear absorption, metabolism, tissue uptake, and renal elimination processes. GHB is a substrate for monocarboxylate transporters, including both sodium-dependent transporters (SMCT1, 2; SLC5A8; SLC5A12) and proton-dependent transporters (MCT1-4; SLC16A1, 7, 8, and 3), which represent significant determinants of absorption, renal reabsorption, and brain and tissue uptake. This review will provide current information of the pharmacology, therapeutic effects, and pharmacokinetics/pharmacodynamics of GHB, as well as therapeutic strategies for the treatment of overdoses. Graphical abstract.

New drug controls and reduced hospital presentations due to novel psychoactive substances in Edinburgh.

AIMS: Recreational use of novel psychoactive substance (NPS) has become increasingly common. We aimed to assess the association of national legislation and local trading standards activity with hospital presentations. METHODS: We established observational cohorts of patients with recreational drug toxicity presenting to Edinburgh Royal Infirmary and dying with detectable recreational drugs in Edinburgh. We assessed associations with two temporary class drug-orders (April 2015: methylphenidates, Nov 2015: methiopropamine), the Psychoactive Substances Act (June 2016), and trading standards forfeiture orders (October 2015). RESULTS: The methylphenidate temporary class drug-order was associated with rapid 46.7% (P = 0.002) and 21.0% (P = 0.003) reductions in presentations and admissions, respectively, for NPS drug toxicity, comparing 12 months before with 6 months after. The change was greatest for ethylphenidate toxicity (96.7% reduction in admissions, P < 0.001) that was partly offset by a tripling in synthetic cannabinoid receptor agonist cases (P < 0.001) over the next 6 months. This increase reversed following trading standards activity removing all NPS drugs from local shops in October 2015, associated with 64.3% (P < 0.001) and 83.7% (P < 0.001) reductions in presentations and admissions, respectively, for all NPS drugs over the next 12 months. The effect was sustained and associated with a reduced postmortem detection of stimulant NPS drugs. The two interventions prevented an estimated 557 (95% confidence interval 327-934) NPS admissions during 2016, saving an estimated £303 030 (£177 901-508 133) in hospital costs. CONCLUSIONS: We show here that drug legislation and trading standards activity may be associated with effective and sustained prevention. Widespread adoption of trading standards enforcement, together with focused legislation, may turn the tide against these highly-damaging drugs.

Effect of rat parental morphine exposure on passive avoidance memory and morphine conditioned place preference in male offspring.

Drug addiction is a chronic disorder resulted from complex interaction of genetic, environmental, and developmental factors. Epigenetic mechanisms play an important role in the development and maintenance of addiction and also memory formation in the brain. We have examined passive avoidance memory and morphine conditioned place preference (CPP) in the offspring of male and/or female rats with a history of adulthood morphine consumption. Adult male and female animals received chronic oral morphine for 21days and then were maintained drug free for 10days. After that, they were let to mate with either an abstinent or control rat. Male offspring's memory was evaluated by step through test. Besides, rewarding effects of morphine were checked with CCP paradigm. Offspring of abstinent animals showed significant memory impairment compared to the control group which was more prominent in the offspring of abstinent females. Conditioning results showed that administration of a high dose of morphine (10mg/kg) that could significantly induce CPP in control rats, was not able to induce similar results in the offspring of morphine abstinent parents; and CPP was much more prominent when it was induced in the offspring of morphine exposed females compared to the progeny of morphine exposed males. It is concluded that parental morphine consumption in adulthood even before mating has destructive effects on memory state of the male offspring and also leads to tolerance to the rewarding effects of morphine. These effects are greater when the morphine consumer parent is the female one.