Pharm 1 - Pharmacodynamics

drraythe's version from 2015-06-14 20:06


Question Answer
What is pharmacotherapy?Restoration of cell & organ fxn- restoration of homeostasis
What is causal therapy? Examples?Elimination of the cause of the Dz. Examples: antibiotics, antiparasitics...cytostatics = cancer therapy (inhibition of cell division)
What is substitution therapy? Examples?To replenish shortages. Examples: Insulin for diabetes, Ca++ for milk fever
Look at the therapy concept chart!He loves it
What is symptomatic therapy? 5 examples?To alleviate pain, suffering, & discomfort. Analgesics, antidiarrheal, spasmolytics-broncholytics, antiarrhythmic, antihistamines
What is prophylaxis?Prevention of Dz (vaccination, immunization)
What is metaphylaxis?Prevention of the (further) spread of Dz [as if, if only a few of the herd are sick, treat all of them]
What is the definition of pharmacodynamics?Study of biochemical & physiological effects of drugs, their mode of action, & the relationship b/t drug concentration & effect (bio/phys effects, mode of action, relationship of conc & effect) (what is does, how it does it)
What is allopathy?Using pharmacological active substance. “(not homeopathy) mainstream medical use of pharmacologically active agents or physical interventions to treat or suppress symptoms or pathophysiologic processes of Dzs or conditions."
What is homeopathy?Dilution = Potentiation. Law of similars "let like be cured by like" ...most likely a crock of poo
What is phytotherapy?Support body fxns (use plant extracts to get certain effects)
What do drugs interact w/ most frequently? Least frequently?Receptors (40%) nuclear receptors (3%).
What are receptors? What do they do?Receptors are signal transducers. They initiate a series of biochemical reactions & alter cellular physiology.
What are 3 effects receptors can have on cells?1) Changes in membrane potential
2) Generation of 2nd messengers (molecules that relay signals from receptors on the cell surface to target molecules inside the cell, in the cytoplasm or nucleus)
3) Protein phosphorylation
Do all drugs bind to receptors?No, not all drugs have specific receptors. Easier to block a specific binding 1, though.
Example of a drug w/ biological specificity?Nicotine. Only affects certain cells, affects a nicotinic receptor which only responds to molecules w/ precisely defined structures
Example of a drug which is not highly specific?Ethanol. It has similar effects in all cells, many lipophilic compounds have similar effects to ethanol
Binding specificity is ___?Reciprocal. Individual classes of drugs only bind to certain targets. Individual targets only recognize certain classes of drugs. A CLOSE FIT b/t drug & receptor is essential
Order of strength of binding forces?Covalent > Ionic > Hydrogen > Van Der Waals > Hydrophobic
What does the example of amitriptyline tell us about selectivity vs specificity?It is not specific to 1 receptor, but is dependent on concentration for which receptor it reacts with. (Diff conc. do diff things) (Dose dependent)
What binding causes a receptor activation?The drug is an agonist, binding elicits a tissue response
What binding causes no receptor activation?The drug is an antagonist, binding elicits no response & prevents binding of agonist.
In terms of drug receptor interactions, what is occupation governed by?Affinity! (How strong it can bind determines if it occupies the site)
In terms of drug receptor interactions, what is activation governed by?Efficacy (effect or no?)
For what do you need affinity for if you are a drug?You need affinity to bind.
Agonists have _________ & _________ activityAffinity & intrinsic activity
Antagonists have _________ & _________ activityAffinity & no intrinsic activity
What is an agonist?A drug which alters cellular responses upon occupancy of receptors
What is a strong agonist?Causes maximal response even when only a small number of receptors are occupied
What is a weak agonist?Only causes maximal response when large numbers of receptors are occupied
What is a partial agonist?A drug which fails to produce a maximal response even when all the receptors are occupied.
What does a full agonist versus a partial agonist look like on a graph of dose & effect? An antagonist?Full agonist will reach 100% then plateau, partial agonist will reach a % that is NOT 100% & then plateau. An antagonist will stay at 0% bc although it binds there will be no effect
What is an antagonist?A drug which binds to the receptor, producing no cellular effect, but inhibits access of agonists to the receptor site hence preventing their effects.
What is a competitive antagonist?Agonist & antagonist utilize the same receptor (**↑ agonist concentrations overrule antagonist's actions.)
What is a non-competitive antagonist?Agonist & antagonist utilize different receptors/binding sites
How does a non-competitive antagonist prevent an agonist from binding?The binding site undergoes a conformational change to prevent agonist binding
What type of antagonist is not overcome by an agonist? Which is?A non-competitive antagonist will NOT be overcome by increasing concentrations of agonist. A competitive antagonist WILL be overcome.
What is a physiological antagonist?2 agonists in unrelated reactions cause opposing effects to cancel each other out (redbull vodka)
What is antagonism by neutralization?2 drugs bind to each other so that each drug becomes inactive
What is an inverse agonist?"Constitutive receptor activation" it causes a receptor to do something...but the opposite of the standard agonist. (Instead of blocking response of cell like an antagonist, it can shut down normal activity)
Example of an inverse agonist?Dopamine-benzodiazepine-serotonin receptors (when on antidepressants Ben is quite contrary)
How does chirality affect binding to receptors?Usually only one chiral form (R or S) can bind to a receptor. Metabolism can often convert the inactive form into the active one. Companies usually put 50% R & 50% S into their formula
What is affinity? What is it measured by?Affinity is the strength of binding b/t drug & receptor. It is measured by the dissociation constant (Kd, 50% occupancy)
What is Kd?Dissociation constant, 50% occupancy of a receptor w/ a drug
What is efficacy?Strength of the response of the drug after binding to the receptor
What is potency?The amount of the drug required to produce 50% of its maximal effects (EC50)...used to compare drugs w/in a chemical class
What is EC50?Effective concentration, 50% clinical effect in 50% of the patients
What is ED50? LD50? TD50?Effective dose 50% effect. Lethal dose 50% effect. Toxic dose 50% effect
What is therapeutic index?B/t ED50 & TD50 (effective & toxic doses)
What does a bigger (wider) therapeutic index mean?It is safer
What is margin of safety?Margin b/t therapeutic & lethal doses of a drug
Receptors can be specific to _________(← part of body)organs
What is receptor up-regulation? What causes it?Continuous use of antagonists means the organ will try to make more receptors
What is receptor down-regulation? What causes it?Continuous use of agonists will cause organ to reduce the number of receptors it has (if overused, a receptor can be "sucked back" into the cell) can be a problem for people taking a medicine all the time
What are 2 types of ion channel receptors?Voltage gated channels (VGC) & ligand gated channels
Examples of voltage gated channels drugs?Local anesthetics, anti-epileptic, anti-dysrhythmic (anti-Anna is an electric topic)
Examples of ligand gated channels drugs?Sedatives, Benzodiazepines, Barbiturates (ligands are "ad" (li) BBS)
What kind of distribution do you need if you want to act on nuclear receptors?Large volume of distribution
Explain cascade of Gi/Go receptors?Inhibit adenylate cyclase, which ↓ cAMP, which leaves more K out of cell (↑ K outflux) & more Ca out of cell too (↓ Ca influx)
Explain cascade of Gs receptors?Activate adenylate cyclase, ↑ in cAMP (which I assume means more K in cell [↓ K outflux] & more Ca in the cell [↑ Ca influx])
Explain cascade of Gq receptors?Activate Phospholipase C, which ↑ [InsP3 (inoitol triphosphate) & Ca2+] conversion of PIP2 (phosphatidyl inositol biphosphate) into DAG (diacylglycerol) → RESULTS IN ↑ IN PROTEIN KINASE C (CIPDC)