Virginia Thornley, M.D., Neurologist, Epileptologist
@VThornleyMD
May 31, 2018
Introduction
Advocacy groups are well-versed and even the public is aware of the increasing popularity of medical marijuana use for medical purposes. Medical marijuana that is all organic all natural with no synthetic materials with high quality have the best-tolerated effects compared to synthetic products. However, with many research studies ongoing, there is the darker side of the equation from which the stigma first grew, its intent for recreation and subsequent abuse. Producers trying to evade the law have come up with far more potent and potentially deadly synthetic cannabinoids which escape detection through laboratory means.
There are spurts of news items regarding the increasing use of synthetic marijuana known as the street name “spice” or “K2.” It first became known in 2008 when the European Monitoring Center for Drugs and Drug Addiction (EMCDDA) identified it as dangerous synthetic cannabinoids from herbal incenses with a remarkable affinity to the CB1 and CB2 receptors which were insidiously abused. These substances were left unchecked because they were initially difficult to identify through biomarkers or testing leading scientists to urgently study these compounds (3).
Typically, presentations occur in groups of patients in the emergency room arising from a single source of distribution at a time. There can be a variety of symptoms because of admixed substances. They have arisen in popularity because they may not be detected by conventional drug testing. Synthetic cannabinoids produce more intense psychoactive effects and by the same token more intense side effects. In animal models, synthetic cannabinoids are 2-100 times more potent than tetrahydrocannabinol in terms of analgesic, anti-inflammatory, anti-seizure effects. It is also thought to be more potent for anti-cancer growth. Because of this, while the beneficial effects are more prominent, by the same token, medical and psychoactive emergencies may result due to its more intense effects through the endocannabinoid pathway. With the added effect of excessive use, this only magnifies the potentiation of effects.
This is likely also the reason why synthetic cannabinoids used medically may provide more benefit, but by the same token are less tolerated and more side effects are noted.
JWH-018 or K2 or Spice and mechanisms
The synthetic cannabinoid “K2” or “Spice” is also known as JWH-018. Dangerous effects of K2 and other synthetic cannabinoids, because they work through the CB1 and CB2 receptors, are potentiations of the usually mild effects of phytocannabinoids from the Cannabis sativa plant. This can lead to changes in the levels of dopaminergic, serotonergic and GABAergic neurotransmitters in the system causing symptoms. There is a high affinity of synthetic cannabinoids to the CB1 receptor through which psychoactive properties of cannabinoids are manifest. It produces similar effects to delta-9-tetrahydrocannabinol which is the psychoactive metabolite from the Cannabis sativa plant but is much more potent. Synthetic cannabinoid metabolites may still remain active and exerts long-lasting effects in addition to the effects of the parent compound. The CB1 receptor is predominantly found in the nervous system while the CB2 receptor is found mostly in the immune system and in other organs to a lesser extent. Synthetic cannabinoids interact with the CB1 receptor pre-synaptically which is a G-coupled protein. Synthetic cannabinoid agonists interact with the CB1 receptor and modulate voltage-gated channels that inhibit sodium, potassium and N-sodium channels and P/Q-type sodium channels thereby reducing the membrane potentials (5).
Synthetic cannabinoids were originally manufactured as a therapeutic agent to exert effects on the cannabinoid receptor.
It is extensively metabolized by cytochrome p450 and activates the cannabinoid receptors (CBR). The most significant cytochrome is CYP2C9 (1) which is found predominantly in the gastrointestinal tract and liver. CYP2C9*1 is the wild type while CYP2C9*2 and CYP2C9*3 are the more common variants. It was found that CYP2C9 *2 tended to metabolize JWH-018 3.6 times more than CYP29C*1 which is likely why there is variation in toxic effects among different individuals when abused (1). Genetic polymorphisms may lead to potentiation of the effects. Other synthetic cannabinoids include JWH-073, CP-47 and 497 (3).
6 other synthetic cannabinoids that have been identified
Six synthetic cannabinoids were characterized from illicit drugs including MMB- and MDMB-FUBINACA, MN-18, NNEI, CUMYL-PICA, and 5-Fluoro-CUMYL-PICA. The toxic effects include cardiotoxicity, seizures and renal damage (2). These have greater effects compared to those of THC. The study shows that synthetic cannabinoids are being manufactured and used as substitutes for THC with greater effects and potentiation (2).
There are hundreds of other synthetic cannabinoids that have been identified.
Dangerous side effects of synthetic cannabinoids
Synthetic cannabinoids affect the gastrointestinal and neuropsychiatric systems and additionally can cause cardiogenic effects. Adverse effects include tachycardia, chest pain, myocardial ischemia, hypertension, confusion, agitation, hallucination, seizures, cerebrovascular vasoconstriction, stroke, and nausea. There have been other reports involving arrhythmias, psychosis, memory loss, cognitive impairment and even fatality (5).
In one study of 141 patients, there were atypical symptoms of psychomotor retardation, hypotension, bradycardia. 75% of blood samples had possibly XLR-11. 24 urine sample came back positive for synthetic cannabinoids, 74% had XLR-11, while 35% had carboxamide indazole derivatives. There were no JWH compounds, opioids, sedative-hypnotics, or imidazoline receptor agonists detected. It is not clear if there may be other undetectable psychotropic agents that may have been mixed causing the unusual symptoms not typical for cannabinoids. In addition, these were patients that came from a nearby psychiatric facility where potentially other neuropsychotropic agents may have interacted (4).
In summary
Clinicians should recognize the clinical symptoms from synthetic cannabinoids and possible adverse side effects as it is emerging as one of the popular drugs of abuse. Once it was discovered there was a ban on synthetic cannabinoids decreasing the wide usage but there has since been a resurgence. They potentiate their pharmacologic effects at the CB1 receptor 2-100 times that of tetrahydrocannabinol but by the same token may cause medical and psychiatric emergencies.
References
- Patton, et al, “Altered metabolism of synthetic cannabinoid JWH-018 by human cytochrome p4502C9 and variants,” Biochem. Biophys. Res. Commun., 2018, Apr., 6, 498 (3):597-602.
- Gamage, et al, “Molecular and behavioral pharmacological characterization of abused synthetic cannabinoids MMB- and MDMB-FUBINACA, MN-18, NNEI, CUMYL-PICA, and 5-Fluoro-CUMYL-PICA,” J. Pharmacol. Exp. Ther., 2018, May, 365(2):437-446.
- Brents, et al, “The K2/spice phenomenon: emergence, identification, legislation and metabolic characterization of synthetic cannabinoids in herbal incense products.” Drug Metab. Rev., 2014, Feb., 46(1):72-85.
- Sud, et al, “Retrospective chart review of synthetic cannabinoid intoxication with toxicologic analysis,” West J. Emerg. Med., 2018, May, 19(3):567-572. doi: 10.5811/westjem.2017.12.36968
- Castaneto, et al, “Synthetic cannabinoids: epidemiology, pharmacodynamics and clinical implications,” Drug Alcohol Depend., 2014, Nov., 1:12-41
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