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Lecture 4
Pharmacodynamics
| Question | Answer |
|---|---|
| Drug-Receptor Interactions: Agonist medications=bind to and activate receptor; receptor activation occurs thru change in ____, incorporation of effector machinery in same molecule, linkage thru ___molecules to a separate effector molecule | conformation, coupling |
| Drug-Receptor Interactions: Pharmacologic antagonist = binds to receptor but ____. binding=____(competitive); ___(noncompetitive) | no activation. reversible. irreversible |
| Drug-Receptor Interactions: Allosteric binding (away from active site)=bind to ___receptor molecule at separate site; does not stop agonist from binding or acting. not usually overcome by increasing amount of agonist | same |
| Receptors: drug receptors normally in ___state | inactive |
| Receptors: constitutive activity = some receptors exist in an active state regardless of an ___; produce some physiologic effect. Agonists have high ___for active state and stabilize it | agonist. affinity |
| Intrinsic Activity: agonist binds to receptor and produces response based on ____of agonist, affinity for ____, fraction of receptors ____. | concentration, receptor, occupied |
| Intrinsic Activity **: Drug's ability to fully activate receptor. Full activation -->intrinsic activity =__ | 1 |
| Types of Agonists**: Full Agonist = activates receptor-effector systems to ___. Intrinsic activity of ____. Stabilizes the receptor in its active state once bound. | maximum extent. 1 |
| Types of Agonists**: Partial Agonists = bind to and activate same receptor but response is ___. Intrinsic activity is _____. May prevent receptor access by full agonist | less. greater than 0 but less than 1 |
| Types of Agonists**: Inverse Agonists=stronger affinity for ___ state --> stabilizes inactive state. Intrinsic activity ____ | inactive, less than 0 |
| Antagonists: bind to receptor with high affinity but does not ____receptor. ___intrinsic activity. Block drug from binding to receptor or prevent activation of receptor. No effect on biological function when an agonist not present. Comp vs. Noncomp | activate. zero |
| Antagonist Classifications**: competitive antagonist = binds ___to same receptor site as agonist. Interferes with agonist receptor binding. Keeps receptor in its inactive state | reversibly |
| Antagonist Classifications**: Noncompetitive/Irreversible Antagonist=____binds to active site of receptor. Not effected by the addition of more ____ | covalently. agonist |
| Allosteric Activity: bind to site ___from agonist binding site --> prevents agonists from ____receptor. Drug modifies receptor activity without blocking agonist binding | separate. activating. |
| Functional Antagonism: occurs when antagonist acts at completely separate receptor resulting in effects ____those of agonist | opposite |
| Chemical Antagonist: makes drug ____for ____ | unavailable. interactions |
| Duration of Drug Action**: Termination Processes = destruction of drug-receptor complex --> ___bound drugs | covalently |
| Types of Receptors: PORE | proteins, orphan, regulatory proteins, enzymes |
| Major Receptor Families: IGEI | Ion channels, G protein-coupled, enzyme-linked, intracellular |
| Ion Channels: __-gated ion channels = extracellular portion of channel has binding site. Binding site controls opening of ___. Channel usually closed until activated by ___ | ligand, pore, agonist |
| Ion Channels: ____gated ion channels = regulate channel function. controlled by ____. Drugs bind to site of receptor different from charged amino acids | voltage. membrane potential |
| G protein Coupled Receptors: extracellular portion ligand binding site; intracellular portion interacts with ____. All composed of 3 protein subunits____ | G protein. Alpha(GTP), Beta and Gamma(anchor G protein in cell membrane) |
| G protein Coupled Receptors: __= receptors for beta amines, histamine, serotonin, glucagon, other hormones | Gs |
| G protein Coupled Receptors: ___= alpha amines, acetylcholine, muscarinic, opioids, serotonin | G1, G2, G3 |
| G protein Coupled Receptors: ___=acetylcholine, muscarinic, bombesin, serotonin | Gq |
| G protein Coupled Receptors: ___receptor family. also called ___or serpentine receptors | largest, seven-transmembrane |
| Enzyme-Linked Receptors: most common enzyme-linked receptors have ____. cause a ____ | tyrosine kinase activity. signal cascade effect |
| ____caused by too much agonist stimulation --> diminished response (tachyphylaxis) | desensitization |
| ____occurs after continuous exposure to drug -->ineffectiveness | tachyphylaxis |
| ____=receptors internalize in cell --> unavailable for interactions | down regulation |
| Refractory period: receptors need a finite time after stimulation before _____can occur again | activation |
| Repeated exposure of receptor to ____results in up regulation of receptors | antagonist |
| Graded Dose-Response Relationship= as concentration of drug increases, its effect gradually ____until all receptors are occupied. curve determines ____ | increases. potency and efficacy |
| ____=measure of amount of drug needed to produce an effect | potency |
| _____=magnitude of response a drug causes when interacting with receptor | efficacy |
| if Kd is low, binding affinity is ___ | high |
| _____= ratio of drug dose that produces toxicity in half the population (TD50) to the dose that produces a desired or effective response (ED50) in half the population. | therapeutic index (TI). measure of drug's safety. determined using drug trials and accumulated clinical experience. high TI values required for most drugs |
| what is the formula for therapeutic index? | TI = TD50/ED50. toxicity/effective response |
| Therapeutic index examples | warfarin=small TI. Penicillin=large TI |
| Target Drug Concentration=concentration of drug that produces desired ____ | therapeutic effect |
| _____= rate of drug elimination equal to rate of drug administration | Steady state |
| Loading Dose Advantages: achieve desired ___level ____ | plasma, rapidly |
| Loading Dose Disadvantages: potential for ____. Takes longer for plasma concentration to ____if excess levels | toxicity. decrease |
| Methods of Fixed Dosing? --> result in time-dependent fluctuations in drug levels | multiple IV injections and oral administrations |
| _____=repeated dosing of meds at regular intervals. Drug accumulation. Steady state. smaller doses at shorter intervals reduces the amplitude of fluctuations | Multiple IV injections: |
| _____= absorbed slowly. plasma concentration influenced by both rate of absorption and rate of elimination | oral administrations |
| _____=drug therapy goal is to achieve, maintain concentrations within therapeutic response window while minimizing toxicity, adverse effects. Drug regimens administered as maintenance doses or loading doses | dose optimization |
| dose adjustments | inter patient variability and differing pharmacokinetic parameters. clearance and Vd. drugs with defined therapeutic range = measuring drug concentrations important in maintaining desired concentration |
| Pharmacokinetic parameters | absorption, clearance, Vd, half life |
| Pharmacodynamic parameters | maximum effect attainable at target tissue, sensitivity of tissue to drug |
| Pharmacokinetic parameters: ____=compliance and rate/extent of absorption, variability in bioavailability | absorption |
| Pharmacokinetic parameters: _____=organ impairment, creatine clearance, liver disease | clearance |
| Pharmacokinetic parameters: _____= protein binding, age, obesity, abnormal fluid accumulation | volume of distribution Vd |
| Timing of samples: absorption typically occurs during first ____hours after administration. avoid drawing blood until ___ complete. | 2. absorption |
| Interpretation of drug concentration measurements: ____=most important factor determining drug concentration | clearance |
| Interpretation of drug concentration measurements: factors influencing clearance | dose, organ blood flow, intrinsic factor of liver or kidney |
| Interpretation of drug concentration measurements: factors influencing protein binding | albumin concentration, alpha 1 acid glycoprotein concentration, capacity-limited protein binding, binding to red blood cells |
| Albumin Concentration: albumin levels low in some diseases --> lower total ___concentation | drug |
| alpha 1 acid glycoprotein concentration: important in ___. quinidine, lidocaine, propranolol, increased in _____ | binding protein. inflammatory disorders |
Created by:
bluedolphin7
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