street and recreational drugs

Street and Recreational Drugs

These terms refer to substances that are commonly misused.

Neuroactive Drugs

Drugs that act in the brain. Their effects can be studied through their impact on behaviour (animal and human, objective/subjective reporting), in vitro/ex vivo/in vivo effects on receptors and signalling, and genetic models.

Dopamine-reward and Positive Reinforcement

A theory explaining that certain drugs increase dopamine inappropriately in the mesolimbic system of the brain, leading to positive reinforcing effects and potential misuse.

Δ 9 Tetrahydrocannabinol (THC)

The primary psychoactive component of marijuana. It binds to CB1 and CB2 receptors in the CNS, inhibiting the release of specific neurotransmitters and mimicking endogenous ligands like anandamide.

CB1 Receptor

A receptor in the CNS that THC binds to, located in areas like the hippocampus, VTA, cerebellum, and somatosensory cortex. Activation inhibits the release of certain neurotransmitters.

Opioids

Natural (opiates) or synthetic compounds including prescription medications like morphine, percocet, oxycodone, fentanyl, and illicit drugs like heroin. They mimic enkephalins and endorphins and are classified by their affinity for opioid receptors (µ, δ, κ).

Morphine

A natural opiate that increases the threshold and tolerance for pain through spinal and supraspinal mechanisms, causes respiratory depression and sedation, euphoria, pupil constriction, and reduces GI contractions. It undergoes significant first-pass metabolism and has an active metabolite. Founds as both L and D isomers

Codeine

An opioid derivative where 10% becomes morphine via the CYP2D6 enzyme.

Heroin

A semi-synthetic opioid about 3 times more potent than morphine, rapidly converted to morphine, highly addictive, and with a short duration of action and euphoric effect. It mimics endogenous compounds binding to opioid receptors.

Fentanyl

A synthetic opioid about 100 times more potent than morphine, sometimes given through a patch. Illicit high-potency opioids like Carfentanil (10,000 times more potent than morphine) are also mentioned.

Benzodiazepines

A class of drugs used clinically as anxiolytics, sedatives, hypnotics, muscle relaxants, and anti-seizure medications, also used in alcohol cessation. They vary in half-life, duration, onset, and selectivity.

Ketamine

A drug that at low doses can cause numbness and low-level anxiety, while higher doses can lead to hallucinations (euphoria) and a 'K-hole'. It increases dopamine efflux and inhibits DAT, contributing to positive reinforcing effects. Used to treat depression

Amphetamines

Psychostimulant. Sympathomimetic drugs that act as 'Fight or Flight' stimulants, with D-amphetamine being more active in the CNS. They increase the release and block the reuptake of dopamine and norepinephrine. Peripheral actions include appetite suppression and increased blood pressure. chemically smiliar to epinephrine and NE

Methamphetamine

A psychostimulant.Similar to strucutre to ephedrine. Increase release of amines. very lipid soluable. Neurotoxic; serotonin and dopamine neuronal death 10hr half life

Cocaine

A psychostimulant that blocks the reuptake of dopamine from the synaptic cleft . Chronic use can deplete intracellular dopamine stores. Crack is a faster-absorbed form with a shorter, more intense effect.

Ecstasy (MDMA)

A drug with both amphetamine and LSD-like properties that increases alertness and energy, fosters feelings of empathy, and increases sensory awareness. It increases the release of serotonin and dopamine and blocks serotonin reuptake, potentially leading to long-term serotonin depletion.

Adulterants

Substances added to street drugs, exemplified by Levamisole adulteration in crack cocaine.

Bioavailability

The fraction of a dose that makes it to systemic circulation in its unchanged form. It is mentioned in the context of different routes of administration for marijuana and MDMA.

t1/2 (Half-life)

The time it takes for the plasma drug concentration to halve. It is mentioned in relation to chronic marijuana use (extended t1/2), morphine (short t1/2 and longer t1/2 of active metabolite), and benzodiazepines (variations in half-life).

First-pass metabolism

Metabolism of a drug occurring before it reaches systemic circulation, often in the liver. It is noted as significant for morphine and absent in sublingual administration.

Pharmacokinetics (PK)

'What the body does to the drug,' including absorption, distribution, metabolism, and excretion (ADME). The PK profile of drugs is associated with illicit use or misuse.

Pharmacodynamics (PD)

'What the drug does to the body,' including the mechanism of action. The PD of misused substances is discussed.

Marijuana onset, duration, peak and half life

20 minutes, 3-6 hours, peak 1-2 hours, half life 56 hours

GPC receptor affinity classification

miu morphine MOP delata dynorphin DOP K ketocyclazocine KOP

Opioid Derivatives

Vicodan, Oxycodone, Fentanyl

BZD MOA physiological effects

GABAergic interneurons act as damper system in CNS which reduced anxiety, increase sedation, memory defects, respiratory depression, etc.

Ketamine route of admin

Snorted or IM

cocaine effects

secondary effects similar to amphetamines (symp activation, inc. duration of action)inc mental awareness, euphoria,halucination, paranoia psychosis

cocaine PK

enters CNS readily, intranasally. onset within minutes then disapears, increases addiction propensity. metabolism via hydrolysis and CYPs.

cocaine overdose symptoms

hyperthermia, cardiac arrhythmias, convulsions, coma death

ecstacy affinity/mechanism

affinity for 5HT2 R. increases release of amines from neuron by reversing transporter action and block reuptake of serotonin

Ecstasy Acute Effects

hyperthermia, dehydration, serotonin syndrom, verbal memory loss, hypertension nausea loss of appetite