Introduction to novel psychoactive substance poisoning
Novel psychoactive substances are designed to mimic established recreational drugs, such as methylenedioxymethaphetamine (methylenedioxymethamfetamine, MDMA, ‘ecstasy’) and cannabis. Novel psychoactive substances are generally more potent than established recreational drugs, and are accessible over the internet and ‘darknet’1. Common street names include ‘bath salts’, ‘flakka’ and ‘spice’. Although these names are associated with certain novel psychoactive substances, they are not reliable terms.
The classic users of these novel psychoactive substances are people who attend commercial dance events and music festivals, ‘e-psychonauts’2 or people who engage in ‘chemsex’3; however, their use has become more widespread with similar distribution to other substance use.
Novel psychoactive substances have rapidly proliferated since the mid-2000s, with hundreds of new substances identified annually. They are broadly categorised into:
- novel stimulant drugs (eg cathinones)
- synthetic cannabinoid-receptor agonists
- novel hallucinogenic drugs (eg ‘2C-B’, ‘NBOMe’)
- sedatives (eg designer benzodiazepines, synthetic opioids such as fentanyl analogues).
The most common novel psychoactive substances are cathinones and synthetic cannabinoid-receptor agonists.
Cathinones comprise a heterogeneous group of ketonated amfetamines with higher toxic potential than established amfetamines. Poisonings most often present with serotonergic and sympathomimetic toxidromes. For management of poisoning due to cathinones and other novel stimulant drugs, see here.
Synthetic cannabinoid-receptor agonists are full agonists at cannabinoid receptors. They cause a hyperadrenergic state with agitation similar to stimulant drug toxicity, followed by late central nervous system (CNS) depression. For management of poisoning due to synthetic cannabinoid-receptor agonists, see here.
Novel hallucinogenic drugs can be dissociative or psychedelic. Poisonings present with features of sympathomimetic or serotonergic toxidromes, and psychotic symptoms. For management of poisoning due to novel hallucinogenic drugs, see here.
Designer benzodiazepines and synthetic opioids are more potent versions of prescription benzodiazepines and opioids. They have a higher risk of CNS and respiratory depression, especially when multiple recreational drugs are co-ingested. Management of poisoning is similar to the management of poisonings due to prescription drugs; see Benzodiazepine poisoning and Opioid poisoning: general management.
As many novel psychoactive substances exist, individual toxic doses are not known and specific investigations or methods to measure concentrations are not available. In some states, the poisons information centre may be able to organise analysis; this is most useful for public health purposes, and is focused on situations where there are clusters of patients and very severe or unusual toxic syndromes.
Management of poisonings due to novel psychoactive substances is complicated by the diverse and nonspecific symptoms of acute intoxication, frequent ingestion of multiple recreational drugs, and the drug(s) taken not being what they were purported to be. Treatment is primarily supportive care. No antidotes are available for novel stimulants, synthetic cannabinoid-receptor agonists or novel hallucinogens. High doses of naloxone may be useful in synthetic opioid (eg fentanyl analogue) poisonings. The antidote flumazenil should be avoided for poisonings with designer benzodiazepines because of the risk of precipitating seizures.