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level: Level 1

Questions and Answers List

level questions: Level 1

QuestionAnswer
What is an agonistA drug which binds to a receptor producing a physiological response within the cell. It has affinity and efficacy
What is an antagonistA drug which binds to a receptor but does not produce a response. It blocks the receptors ability to be activated by an agonist. Competitive and non-competitive.
Competitive antagonist dose response curveParallel shift to the right, reaches max response
Non competitive agonist dose response curveDownward non parallel shift
Name the 2 branches of the Autonomic Nervous SystemSympathetic and parasympathetic
Branch of ANS associated with fight or flight?Sympathetic
Branch of ANS associated with rest and digest?Parasympathetic
Neurotransmitter released by sympathetic NS?Norepinephrine
Neurotransmitter released by parasympathetic NS?Acetylcholine
Sympathetic NS effectsIncreased HR, constricted blood vessels, dilated bronchioles, decreased digestion - FIGHT OR FLIGHT
Parasympathetic NS effectsDecreased HR, dilated blood vessels, constricted bronchioles, increased digestion - REST AND DIGEST
After sympathetic response, how is norepinephrine removed from synaptic cleft?Reuptake into the presynaptic terminal via Norepinephrine transporter (NET)
After parasympathetic response how is acetylcholine removed?Acetylcholine degraded by acetylcholinesterase into choline and acetic acid - choline transported back into presynaptic terminal and used in synthesis of new acetylcholine - acetic acid diffused into tissue
Types of acetylcholine receptorsNicotinic and muscarinic
Types of noradrenaline receptorsAlpha adrenergic receptors (blood vessels), beta adrenergic receptors (heart)
Beta adrenergic agonist and antagonistAgonist = salbutamol and noradrenaline, antagonist = propranolol
Muscarinic receptor agonistAtropine
Hepatic portal systemVeins carrying blood from GI tract to liver. Hepatic portal vein delivers deoxygenated blood from small intestine to inferior vena cava. Hepatic artery delivers oxygenated blood.
Opioid receptorsMu, delta, kappa, ORL-1. G protein coupled receptors. Metabotropic
What are endogenous agonistsEndorphins - modulate mood and response to pain
Effects of heroinEuphoria, drowsiness, dry mouth, flushed skin - short term
Parenteral routes of administrationIV, transdermal
Enteral routes of administrationOral, rectal
Which organ is mainly responsible for drug metabolism?Liver
Which part of the brain do you associate with psychological addiction?Mesocorticallimbic dopaminergic pathway
Naloxone effectsImmediate withdrawal symptoms
Misuse of Drugs Act 1971 (MDA 71)Defines what it is legal to do with the drugs it controls
Misuse of Drugs Regulations 2001 (MDR 2001)Lists restrictions and exemptions to MDA 71 - also explains what is not an offence (drs, chemists)
In MDA 71 what class of drugs are common opiates and why?Class A - most harmful - morphine, morphine in low dose form, raw opium, medicinal opium Class B - codeine (unless injected)
In MDR 2001 what schedules do main opiates fall into and why?Schedule 1 = raw opium; Schedule 2 morphine + medicinal opium + codeine; Schedule 5 = low dose morphine, low dose codeine (min risk of abuse)
Legitimate morphine sources contributing to a positive urine resultPrescription pain killers (codeine, fentanyl, morphine), cough syrup containing codeine, ingestion of products containing poppy seeds
Illegal sources of morphine contributing to a positive urine resultAbuse of prescription drugs, illicit drugs (heroin)
CASE STUDY Positive workplace drug testing result for morphineIf no solid state drugs recovered individual cannot be charged due to positive test alone. Positive test may be due to drug metabolites from legitimate use (prescription codeine/morphine). Ingestion of food products containing poppy seeds. Urine sample should be tested for other metabolites (6-MAM indicates heroin use). Codeine:Morphine ratio <6 indicates an additional source of morphine present. No previous drug use known, no drugs recovered, signed document - may be dismissed from job
Effects of opioids on mu receptorAnalgesia, euphoria, sedation, constipation, respiratory depression, withdrawal
Mu opioid receptor experimentTransgenic mouse - 1 wild type (normal), 1 knockout (modified opioid gene OPMR-1) - after opioid administration normal mouse has all physiological effects, knockout has none due to no mu receptors.
PharmacokineticsWhat the body does to the drug (ADME)
PharmacodynamicsWhat the drug does to the body (receptor binding, symptoms)
Opioid pharmacokineticsADME: Absorption, Distribution, Metabolism, Excretion A: IV - fast as no absorption phase, rapid increase in drug concentration in the brain. Oral - no euphoria, slow absorption, no sudden increase in drug concentration. D: CNS, crosses blood brain barrier (BBB) M: Liver - phase 1 (oxidation or hydrolysis), phase 2 (conjugation) - slow metabolism may cause overdose, may prolong drug effects E: kidneys - excreted as metabolites - depends on kidney function, reduced in elderly prolongs drug effects. Exception - methadone excreted via bile
Mu receptor effectsAnalgesia, euphoria, sedation, respiratory depression, constipation, pupillary constriction
Delta receptor effectsAnalgesia, proconvulsant
Kappa receptor effectsAnalgesia, sedation, pupillary constriction, dysphoria
ORL-1 receptor effectsAnalgesia, immobility, impairment of learning
Opioid use symptomsAnalgesia, euphoria, sedation, constipation, respiratory depression
Withdrawal symptoms (physiological)Aggression, nausea, shaking, pain, hallucinations - Temporary
Addiction symptoms (psychological)Changes in mesocorticallimbic dopaminergic pathway - craving - permanent
Opioid addiction treatmentMethadone - potent Mu agonist - orally = slow absorption, long lasting, slow release, no euphoria. Misused to achieve euphoria LAAM - potent Mu agonist - orally 3x per week Buprenorphine - partial agonist - reduces withdrawal - orally 3x per day. Misused Suboxone - combines buprenorphine and naloxone - sublingual or buccal (dissolved in mouth) - naloxone deterrent prevents misuse - if taken orally naloxone results in immediate withdrawal symptoms
Opioid toxicity symptomsCNS depression, respiratory depression, constricted pupils, drowsiness
Relapse after abstinenceDecreased tolerance levels may lead to overdose if previously acquired tolerance dose administered
Metabolites of morphineMorphine, hydromorphone, codeine
Heroin metaboliteMorphine, 6-MAM (only source is heroin)- Detection time 8hrs
UK maximum penalties under MDA 71Possession: Class A = 7 years & fine, class B = 5 years & fine, class C = 2 years & fine Supply: A = life & fine, B = 14 years & fine, C = 14 years & fine
Morphine levelsOral - 10mg/5ml tablet; Fast reaction tablets 20 or 50mg; slow tablets 5-200mg; liquid, 10mg in 5mL; injection 10mg/1ml, iv 2.50-10mg/ml muscle 5-20mg
MDR 2001 Schedules1 = most stringently controlled (research) 2 & 3 = controlled drugs with a medical use - can be prescribed 4 = minor prescribed tranquilisers 5 = minimal risk of abuse - sold over the counter
Advantage of morphine administration into spinal cordLower risk of respiratory depression as further away from brain
Gamma-Amino-Butyric Acid (GABA) - ADDICTIONInhibitory neurotransmitter blocks impulses between nerve cells and the brain (CNS) - Inhibits dopamine release Opioid (Mu) receptors on GABA neuron nerves - opioid may bind and inhibit GABA = increased dopamine production = euphoria Desensitisation in heroin addicts - need a higher dose for response
Morphine ADMEA – IV – rapid increase in drug concentration within the blood leading to the brain – faster route as no absorption phase – long lasting Oral – 40-50% of dose reaches CNS (30 mins for immediate release morphine, 90 mins extended release form) - Absorbed in the small intestine D – Liver, kidney, lungs or spleen, crosses BBB M – Metabolised in liver by demethylation and glucuronidation Metabolites = M6G, M3G, codeine, hydromorphone and normorphine Phase 1 and phase 2 by enzymes E – Metabolites eliminated via renal filtration - Elimination ½ life = 120 mins
Morphine daily doseDifferent doses dependent on preparation type – maximum dose within a 24 hr period - max 120mg for morphine