Drugs and Addiction: An Introduction

Introduction to Drugs and Addiction

• A drug is a chemical substance altering biological functions or structure when introduced.
• A psychoactive drug affects the mind, leading to changes in mood, cognition, and behavior.
• The blood-brain barrier is a selective membrane protecting the brain.
• The federal drug scheduling system classifies controlled substances by abuse potential, dependence potential, and medical approval.
• Schedule 1 drugs have no accepted medical use and a high abuse potential.
• Schedule 2 drugs have a high abuse potential and can lead to dependence.
• Schedules 3, 4, and 5 have progressively lower abuse potential.
• Cocaine, methamphetamine, LSD, psilocybin, and alcohol have different drug schedules.
• Cocaine and methamphetamine are schedule 2.
• LSD and psilocybin are schedule 1.
• Alcohol is not on the schedule.
• Drugs are categorized as stimulants, depressants, or hallucinogens, and can be natural or synthetic.
• Stimulants include nicotine, cocaine, ecstasy, and amphetamines.
• Depressants include alcohol, weed, benzos, heroin, opioids, and sedatives.
• Hallucinogens include LSD, ecstasy, and psilocybin.
• Natural drugs include weed.
• Synthetic drugs include LSD, ecstasy, and meth.
• A semi-synthetic drug is heroin.

Definitions of Dependence and Addiction

• Psychological dependence is an emotional need without physical cause, marked by strong craving.
• Physical dependence involves bodily changes adapting to the drug.
• Addiction is compulsive drug use despite negative consequences.
• Addiction involves cyclical patterns, impacting social commitments, and driving drug-seeking behavior.

DSM-5 Changes and Substance Use Disorder

• The DSM-5 defines substance use disorder based on criteria like social impairment, risky use, impaired control, and pharmacological dependence.
• Social impairment includes neglecting responsibilities, relationship problems, and sacrificing activities.
• Risky use involves physical or psychological dangers.
• Impaired control means using large amounts, struggling to cut down, and experiencing cravings.
• Pharmacological dependence includes tolerance and withdrawal symptoms.

Pharmacology Basics

• Pharmacology studies the uses, actions, and effects of drugs.
• Pharmacokinetics describes what the body does to a drug, involving absorption, distribution, metabolism, and elimination (ADME).
• Absorption is the drug's movement from administration site into the bloodstream.
• The route of administration (ROA) affects drug absorption rates.
• Different ROAs influence how quickly and how much of the drug enters the bloodstream.
• Oral ROA is safe, easy, and economical, but has slow and variable absorption, and subject to the first-pass effect.
• Rectal ROA is quicker than oral, useful when vomiting or unconscious, but has variable absorption.
• Vaginal ROA offers steady drug levels directly to the tissue, but can cause irritation.
• Sublingual ROA enables rapid absorption and higher bioavailability, but has limitations.
• Intranasal ROA provides rapid absorption and local/systemic effects, but can irritate.
• Eye/Ear drops deliver drugs directly, but administration is difficult.
• Transdermal ROA is easy, noninvasive, and slow, but not suitable for all drugs.
• Inhalation allows for very rapid onset, but irritates lungs/nasal passages.
• Intravenous ROA is rapid and accurate, but expensive and irreversible.
• Intramuscular ROA offers sustained release, but causes pain and irritation.
• Subcutaneous ROA allows self-administration with variable absorption.

Distribution, Metabolism and Elimination

• Distribution transports drugs to their action site.
• Toxic drugs accumulating in organs can cause damage and failure.
• The blood-brain barrier prevents harmful substances from entering the brain.
• Metabolites are products of drug breakdown.
• Liver is involved in drug metabolism.
• The most common enzyme family for metabolizing drugs is CYP450.
• First-pass metabolism reduces bioavailability, affecting orally administered drugs.
• A drug depot is a body area where drugs accumulate without a biological effect.
• The first-pass metabolism effect reduces bioavailability.
• Drugs are typically eliminated via kidneys (urine), GI tract (feces), lungs, and skin (sweat).
• Half-life is the time for drug concentration to reduce by 50%.

Pharmacodynamics and Neurotransmitters

• Pharmacodynamics outlines what drugs do to the body.
• Neurotransmitters are chemical messengers released into synapses.
• Receptors are specialized proteins on neuron membranes that drugs bind to.
• A ligand is a substance that binds to a receptor.
• Neurotransmitters are removed from the synapse through reuptake or degradation.
• Agonists enhance neurotransmitter activity, while antagonists block or inhibit it.
• Drugs can act directly or indirectly.

Addiction and the Brain

• The mesolimbic dopamine pathway (reward pathway) involves the prefrontal cortex, nucleus accumbens, and ventral tegmental area (VTA).
• Dopamine is crucial for memory formation and motivates repeating pleasurable experiences.
• The VTA produces dopamine, and the nucleus accumbens drives motivation.
• Acute toxicity involves single doses, while chronic involves long periods, both potentially reversible.
• A dose-response curve shows effect relative to dosage.
• ED50 is the effective dose for 50% of the population.
• LD50 is the lethal dose for 50% of the population.
• The therapeutic index (TI = LD50/ED50) indicates drug safety, with larger numbers being safer.
• Tolerance is reduced drug effect with use, including metabolic, cellular, behavioral, and cross-tolerance.
• Sensitization increases response with repeated use and selective tolerance differentiates effects.
• Withdrawal occurs when homeostasis is disrupted after drug adaptation.

Stimulants and Catecholamines

• Cocaine comes from the coca plant, while methamphetamine and amphetamine are synthetic.
• Cocaine, methamphetamine, and amphetamine are Schedule 2 drugs.
• Catecholamines include dopamine, norepinephrine, and epinephrine
• Catecholamines impact motor skills, emotions, learning, memory, and alertness.
• Coca leaves are chewed in natural growing areas for minimal effect.
• Coca leaves can be combined with lime to enhance absorption.
• Cocaine can't be smoked due to water solubility.
• Crack cocaine is smoked to produce a quick/intense high.
• Freebase cocaine involves separating for higher lipid solubility and is smoked.
• Routes of administrations impact drug onset and duration.
• Cocaine is water-soluble, absorbed in minutes.
• Crack is absorbed through the lungs instantly.
• Freebase is separated, more easily crosses the BBB, and is smoked.
• Cocaine, is widely distributed and metabolized in the liver.
• Cocaine can cause pseudocholinesterase deficiency.
• Cocaine and metabolites detectable in urine.
• Half-life of cocaine is approximately one hour, but will vary.

Stimulants Effects on the Neurons

• Dopamine-reuptake transporters are blocked.
• Agonists increase levels of catecholamine.
• Euphoria and bursts of energy result.
• High doses causes purposeless behavior.
• Toxicicity results in perforated septum and lung damage.
• The heart system strain increases stroke risk.
• Tolerance to euphoria and energy occurs.
• DA receptors are fewer and less responsive
• Sensitization happens to motor effects.
• Stimulant withdrawal includes symptoms of depression and anxiety.

Amphetamine and Methamphetamine

• Methamphetamine is more potent than amphetamine due to modifications and effects on neurotransmitter release.
• OTC ingredients can be used to make meth.
• Manufacturing meth is dangerous.
• Amphetamine is mainly orally administered.
• Lungs are used smoking meth.
• Meth is more lipid-soluble.

Stimulants Brain Effect

• Dopamine levels are increased.
• Noradrenaline and serotonin are blocked.
• The axon terminal is taken into axon terminal.
• Storage vesicles are replaced with dopamine.
• Hallucinations and paranoia characterize psychosis.
• Contingency management and CBT help treat patients.
• Patients are rewarded to stay abstinent
• CBT helps focus and motivate.
• No FDA medicines are approved to use.

Alcohol

• Alcohol is a depressant.
• Alcohol is used socially, not medical.
• Alcohol is ethyl & fermented into alcohol by yeast
• Alcohol proof is twice the % of ETOH
• 18 mL or 14 g of alcohol are what consist of a standard drink.
• Alcohol’s metabolic process involves 3 enzyme: alcohol dehydrogenase (ADH), acetaldehyde dehydrogenase (ALDH), and Acetyl CoA.
• Alcohol is metabolized as it is consumed.

Alcohol’s Effects

• GABA is the neurotransmitter most affected.
• Glutamate and Dopamine activity fluctuate
• Behavioral disinhibition, cognition, and motor skills can be affected.
• Hangovers are caused by an acute alcohol withdrawal.
• Acute alcohol withdrawal, dehydration, and Gl irritation result in hangovers.
• Alcohol consumption can affect the state of the liver over time.
• Liver cirrhosis can occur

Alcohol: Tolerance & Withdrawal

• Cellular tolerance causes increased glutamate receptors.
• Anxiety and insomnia result.
• Delirium tremebs can result.
• Valium is used to treat serious withdrawal
• Antabuse/Disulfiram is used to avoid relapse

Alcohol: Blocking Metabolism

• Alcohol levels are blocked.
• AA encourages sponsorship for those in the program.
• Secular problems are used to create SMART.

Hallucinogens

• LSD and Psilocybin drug distorts sensation.
• Psilocybin are used in rituals.
• Lysergic acid concept is used for LSD.
• Liquid can absorbed into the mucosa
• LSD is potent
• Serotonin is affected in these drugs.
• Anxiety, heart rate occur due to these drugs.
• Short tolerance develops.
• Flashbacks can occur.
• very low potential for addiction
• Cluster HA are treated.