Question | Answer |
The drugs job (i.e. get to the right binding site, fit snugly, turn receptor on/off or just occupy the site) is pharmacodynamics or pharmacokinetics? * | Pharmacodynamics |
The body's job (i.e. to try prevent drug entry to tissues, manage drug if it does get in (break it down, eliminate it) is pharmacodynamics or pharmacokinetics? * | Pharmacokinetics |
What are the pros and cons of taking a drug orally? | PRO: Easy, preferred ROA. CON: Slow time of onset, especially in fed state, decreased bioavailability, peptide degraded |
What are the pros and cons of taking drugs sublingually? | PRO: Easy, faster onset than oral, better bioavailability than oral. CON: Not many drugs can be absorbed this way. |
What are the pros and cons of IV, IP, IM, SC route of administration? | PRO: Rapid onset (can be positive or negative), IV has optimal bioavailability. CON: once injected its non reversible, is aversive, skilled techniques are required, infection risk |
What are the pros and cons of Inhalational route of administration? | PRO: Rapid onset, better bioavailability than oral. CON: Not many drugs can be easily volatized, health risk if combusted |
What are the pros and cons of taking drugs via insulfation? | PRO: Faster onset than oral, better bioavailability than oral. CON: tissue damage to nose & vasculature, generally aversive. |
What are the pros and cons of Rectal route of drug administation? | PRO: useful of oral ROA not practical (person vomitting), better bioavailability than oral. CON: generally aversive. |
What are the pros and cons of taking drugs Transdermally? | PRO: Easy, non invasive ROA. CON: Not many drugs can be absorbed this way. |
Describe what pharmacokinetics stands for. | Pharmaco = drugs. Kinetics = movement/time. How the drug moves through your body and the processes that occur during that journey. |
What are the 4 subdivision of pharmacokinetics? * | Absorption, Distribution, Metabolism, Elimination |
Describe the subdivision Absorption of pharmacokinetics * | Absorption = movement of drug into the bloodstream. |
Describe Bioavailability * | The portion (%) of administered drug that reaches the systemic circulation. Different drugs have different bioavailability |
What are the three factors that affect absorption? * | - The drug molecule itself (particle size(tiny), ionization, lipothilic) - The route of administation e.g. IV injection means 100% bioavailabiltiy so all the drug is absorbed directly into bloodstream. - First-pass metabolism (needs to get past liver) |
Describe the first-pass metabolism. Find out what exactly need to say for this first. | ... |
Describe distribution * | Movement of the drug from the bloodstream into TISSUES |
What are the factors that effects DISTRIBUTION of drug from the blood to the tissue? * | 1. The drug molecule itself(tiny and lipothilic then will get out of blood and into tissue easier). 2. Perfusion of tissue/amount of tissue (easier to distribute into tissue of child than adult. 3. Kind of tissue. 4. Protein binding. See lecture notes |
The portion (%) of a drug that gets bound to protein gets distributed. T or F? | False it cant get distributed into tissue as it is no longer tiny and lipothilic. |
What is the first attempt of metabolism called? | First-Pass metabolism |
What is the second parts of metabolism called? | Phase I and Phase II metabolism |
What does 'Half-life (t - 1/2)' refer to? | = time required to metabolism 50% of the drug. So not dependent on concentration |
What is an example of a Pro-Drug? and describe what this means * | Codeine. Its a drug that actually needs to go through metabolism to actually become active. Codeine turns into morphine by going through FPM. |
Describe Metabolism * | Enzymatic breakdown of drug |
What are the 2 factors (including 3 subpoints of second factor) that effect metabolism? * | 1.Liver function (how well lover is working, if unwell from alcohol or hepititis then metabolism wont work as well). 2.Enzyme function (Genetics - asians don't have enyzyme to turn codeine into morphine, Enzyme workload, enzyme induction.see lecture notes |
Why is half-life important? (2 reasons) | 1. It is key to effective drug presribing e.g. Lorazepam v.s. Triazalam (drugs for imsomnia). 2. Is key to effective dosing regimens - how regularly you take the drug. |
Define 'Elimination' as the fourth phase. * | The removal of the drug from the body (clearance) |
What are the 5 routes of elimination? * | Renal (via the kidney, most common), Billiary (fecally), Exhalation (alcohol), lactation (breastfeeding), Perspiration (minor route through sweat - not alcohol) |
Pharmacodynamics is all about the ....? | design of the drugs |
Who first described "receptive substance" in tissue? * | John Langley |
Who first defined 'receptor' and the Magic Bullet idea? * | Paul Ehrlich |
What did Otto Loewi do? * | He showed that neurons release some substance capable of exerting physiological effects in another tissue preparation - showed that neurons communicate via chemicals. |
What experiment did Otto Loewi do? Draw the diagram. | The frog heart experiment. |
Why is Otto Loewi's finding important? * | Because it showed that neurons must release chemicals and that tissues must have receptors for these chemicals. |
What did Henry Dale find? * | That Acetylcholine (ACH) can slow and fasten responses so shows that there are Receptor subtypes. Showed that you can use exogenous chemicals to mimic endogenous chemical. |
What experiment did Henry Dale do? Draw the diagram. * | The skeletal muscle and heart experiment |
Why is Henry Dale's findings important? (two reasons) * | Because we now know that one endogenous neurochemical can have both +/- effects which suggests that there are receptor subtypes. Also that we can mimic the +/- effects by using exogenous chemicals. |
Ligands can be e______________ (NT) or e_____________ (drug) | Endogenous, Exogenous |
Good ligands should have what two attributes? | High affinity (hot tightly they fit into receptor), Selectivity |
Some ligands also need? | Efficacy (be an agonist rather than an antagonist). |
What attribute of ligands are a bonus? | Potency, with very potent drugs you don't need as much dose. |
Go over the different Receptor Ligands - GABA, alcohol, Valium, bicuculline. | ... |
What are they three different manipulations that are drug can be? | Agonist, Antagonist, Inverse Agonist. |
A drug that binds to a receptor and 'turns it on' is a what? | Agonist |
A drug that binds to a constitutively active receptor and turns it off is a what? (would use this is receptors are doing something bad all the time to shut it down) | Inverse Agonist |
A drug that binds to a receptor but does not activate it is a what? | Antagonist |
Membrane Receptors can be ? | Ligand-gated ion channels, G-protein coupled receptors, tyrosine kinases, nuclear receptors |
What are the two types of classes/types of Receptors that we will focus on? | Ionotropic Receptors (receptor itself is an ion channel) and Metabotropic Receptor (G-protein receptors) |
What are the 3 attributes of Ionotropic Receptors? | fast acting (changes (incr or decr. excitability fast), Opens/closes channel, short duration effect |
What are the 3 attributes of Metabotropic Receptors? | Slow acting, diverse range of effects, long lasting effect |
There are 3 different types of G-proteins. What are they? | Gs (Stimulatory), Gi (inhibitory), Gq |
What does the Gs protein do? | It activates AC (adenylate cyclase) so makes cAMP (?) to send message downstream. |
What does Gi protein do? | Inhibits AC (adenylate cyclase). |
What does Gq protein do? | It activates PLC to make 2nd messenger DAG & IP3 |
What are the four major steps of Synaptic Transmission? | 1. Synthesis and packaging of neurotransmitter. 2. Release of neurotransmitter, 3. Binding of neurotransmitter to post-synaptic receptors. 4. Clearance of neurotransmitter via enzymatic breakdown and /or reuptake transporter. |
What are the 4 major targets/aims of psychoactive drugs? * | see revision notes |
Define drug tolerance. * | Decreased responsiveness to drug |
Define drug dependence * | Physiological withdrawal symptoms upon cessation of the drug. |
What type of tolerance is this? "Receptor desensitisation and/or downregulation of receptor number" | Pharmacodynamic tolerance |
What type of tolerance is this? "Metabolism increased because CP450 enzymes upregulated (so less gets distributed to the brain)" | Pharmacokinetics tolerance |
What type of tolerance is this? "Behavioural conditioning to counterbalance effects (e.g. if you drink every day at 5pm)" | Contextual tolerance |
Withdrawal symptoms (in relation to drug dependence) indicates that new h___________ has been achieved during drug use. | homeostasis |
What is a drug-drug interaction? | One drug alters the effect of another. |
The drug-drug interaction can be pharmaco___________ (e.g. CYP induction, renal clearance - kidneys dont filter at the same rate). The drug-drug interaction can be pharmaco___________ (e.g. valium + alcohol = addictive GABA(A) effect) | kinetic, dynamic |
Valium is a ? | Depressant |
Are drug-drug interactions seen as good or bad? | Bad. We want to avoid and minimise them. Unless to reverse the overdose of a drug like alcohol for example. |
What does does a therapeutic window mean? * | The rang of drug dosage which can be effective whilst staying within the safety range. |
If a drug has a narrow therapeutic window, what does this mean? * | It means that there is only a small dosage where the drug is therapeutic and will therefore go from therapeutic to toxic with only a small amount in the blood |
What kind of dosing schedule is needed to reach a steady state within the optimal therapeutic dose? * | The amount you administer each dose at each half-life (time required to metabolise 50% of the drug) e.g. take another dose every 4 hours if the half life is 4 hours. So would reach steady state in 5-6half lives (20-24 hours). |
Is there any way you could shorten the time it takes to reach a steady state? * | Yes, have a large dose for the first dose only = loading dose e.g. take 100mg to get concentration up immediately and then 50mg from then on. |
Why is receptor theory important for a course in Drugs and Behaviour? Appreciate the contributions of Langley, Ehrlich, Loewi and Dale. * | In revision book. Memorise |
What did John Langley do? * | He described 'receptor substance' in tissues |
What did Paul Ehrlich do? * | He defined 'receptor' and the Magic Bullet idea |
What did Otto Loewi do? * | Showed that neurons release substance capable of exerting physiological effects in another tissue preparations. This is important as it tells use that neurons release chemicals to communicate & that tissue have receptors for those chemicalsegfrog/HR/water |
What did Henry Dale do? * | Showed that ACh can slow and fasten responses of cells/organs. This is important as it shows us that there are receptor subtypes and that we can mimic +/- effects using exogenous chemicals. |
Define agonist * | A drug that binds to a receptor and 'turns it on' |
Define anatagonist* | A drug that binds to a receptor but does not activate it, just occupies it |
Define Inverse Agonist * | A drug that binds to a constitutively active receptor and turns it off. (if receptor is active all the time you want to shut it down). |
What is a Ligand? * | A molecule that binds to a receptor such as a drug, ion or hormone. It has the following characteristics: exogenous or endogenous, agonist/antagonist/inverse agonist, high/low affinity, high/low efficacy and high/low potency. |
Define affinity * | Affinity refers to how well the ligand (drug) fits into the receptor. A ligand with high affinity fits perfectly and with low affinity it might fall out, sort of fits. |
Define efficacy * | Efficacy refers to the degree of effect that a ligand (drug) has. High efficacy means high effect e.g. an agonist and antagonist both have good efficacy as turn on/off. But inverse agonist has no efficacy as it has neutral effect. |
Define potency * | Potency of ligand/drug refers to how strong in concentration the ligand is e.g drugs with high potency you only need 1mg but low potency you need 10mg |
Compare and contrast metabotropic and ionotropic receptors * | See revision notes! |