[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › Drugs of abuse # Drugs of abuse Psychoactive substances used outside medical care: stimulants, hallucinogens, dissociatives, cannabinoids, inhalants and sedative adulterants. Updated Nov 1, 2026 ## What they are A group defined by use, not by chemistry. Each substance acts on a known brain target, and the clinician meets them as acute intoxication, withdrawal, a substance use disorder or a complication such as hyperthermia, psychosis or wounds. Street products are often mixed or adulterated, so the label rarely matches the content. In Colombia the national toxicology guide describes amphetamine-type drugs, «2CB», synthetic cannabinoids and mixtures sold under street names. ## Mechanism of action Stimulants (methamphetamine, MDMA) release dopamine, noradrenaline and serotonin through their transporters. Classic psychedelics (LSD, psilocin) activate serotonin 5-HT2A receptors. Dissociatives (phencyclidine) block NMDA glutamate receptors. Cannabinoids act on CB1 receptors. Inhaled solvents depress the brain much like anaesthetics, and xylazine is an alpha-2 agonist that adds sedation to illicit opioids. Target: Monoamine transporters, 5-HT2A, NMDA, CB1 and alpha-2 receptors ## Key points - Sympathomimetic picture (tachycardia, hypertension, hyperthermia, mydriasis, agitation): stimulants; benzodiazepines are first line for agitation. - MDMA: serotonin release, hyperthermia, serotonin syndrome and hyponatraemia from drinking large volumes of water. - LSD and psilocybin act on 5-HT2A; PCP blocks NMDA and causes nystagmus, agitation, hyperthermia and sometimes violence. - Synthetic cannabinoids are high-efficacy CB1 agonists missed by routine urine screens; xylazine is not reversed by naloxone. - Most intoxications have no specific antidote: supportive care, cooling, benzodiazepines and screening for mixtures. ## Drugs in this class - [**MDMA (midomafetamine)** A synthetic amphetamine («ecstasy») with stimulant and mild psychedelic effects; it floods the brain with serotonin… Monoamine transporters: serotonin transporter (SERT) first, plus VMAT2](https://durgical.com/en/pharmacology/mdma/) - [**Methamphetamine (metamfetamine)** A potent synthetic stimulant with high addiction potential. A prescription form exists for ADHD in some countries… Dopamine and noradrenaline transporters (DAT, NET) and VMAT2; also the receptor TAAR1](https://durgical.com/en/pharmacology/methamphetamine/) - [**Cannabis** The plant Cannabis sativa; its main psychoactive compound, THC, acts on CB1 receptors. Widely used; medical-use… Cannabinoid receptor 1 (CB1); CB2 on immune cells](https://durgical.com/en/pharmacology/cannabis/) - [**Lysergide (LSD)** A very potent semi-synthetic psychedelic that activates serotonin 5-HT2A receptors; it alters perception for many… Serotonin 5-HT2A receptor (also other 5-HT and dopamine receptors)](https://durgical.com/en/pharmacology/lysergide/) - [**Phencyclidine (PCP)** A dissociative drug («angel dust») that blocks NMDA glutamate receptors; it can cause psychosis, violent agitation… NMDA glutamate receptor channel (pore site shared with ketamine)](https://durgical.com/en/pharmacology/phencyclidine/) - [**Psilocybin** The psychedelic in «magic mushrooms» (Psilocybe species). The body turns it into psilocin, which activates 5-HT2A… Serotonin 5-HT2A receptor (via its active form, psilocin)](https://durgical.com/en/pharmacology/psilocybin/) - [**Inhaled solvents** Glues, thinners, fuels and aerosols whose vapours are inhaled, mostly by adolescents. One session can trigger a fatal… NMDA and GABA-A receptors and other ion channels (anaesthetic-like actions)](https://durgical.com/en/pharmacology/inhaled-solvents/) - [**Synthetic cannabinoids** Lab-made CB1 agonists sprayed on plant material or put in vape liquids («K2», «Spice»). Far stronger than THC and… Cannabinoid receptor 1 (CB1)](https://durgical.com/en/pharmacology/synthetic-cannabinoids/) - [**Xylazine** A veterinary sedative («tranq») mixed into illicit fentanyl and heroin. An alpha-2 agonist, not an opioid: naloxone… Central alpha-2 adrenergic receptors (like clonidine)](https://durgical.com/en/pharmacology/xylazine/) - [**Diamorphine (heroin)** Heroin: an opioid made from morphine. A rush, then drowsiness and slowed breathing; overdose kills by respiratory… Mu-opioid receptor (after conversion to morphine)](https://durgical.com/en/pharmacology/diamorphine/) ## Others in the class - Cocaine (stimulant) - Synthetic cathinones («bath salts») - 2C-B and other phenethylamines - Ketamine (dissociative) - Alcohol, opioids and sedatives (see their own classes) ## Test yourself Think of the answer, then tap the question to see it. ## Which receptor do LSD and psilocin mainly activate? The serotonin 5-HT2A receptor. ## Which drug class is usually first line for stimulant-induced agitation? Benzodiazepines; antipsychotics lower the seizure threshold and are second line. ## Why can an overdose mixed with xylazine fail to respond fully to naloxone? Xylazine is an alpha-2 agonist, not an opioid, so naloxone does not reverse its sedation. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/classes/drugs-of-abuse/) [More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology) [← All of pharmacology](https://durgical.com/en/pharmacology/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [Guía para el Manejo de Emergencias Toxicológicas](https://minsalud.gov.co/sites/rid/Lists/BibliotecaDigital/RIDE/DE/GT/guias-manejo-emergencias-toxicologicas-outpout.pdf) (Ministerio de Salud y Protección Social; Organización Panamericana de la Salud, 2017); [Drugs A to Z](https://nida.nih.gov/research-topics/commonly-used-drugs-charts) (National Institute on Drug Abuse (NIDA), 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/classes/drugs-of-abuse/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/classes/drugs-of-abuse/