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Flashcards in IB - Introduction To Pharmacology Deck (50):

What are the different branches of pharmacology?

  1. Physchopharmacology
  2. Clinical pharmacology
  3. Veterinary pharmacology
  4. Pharmaceutical sciences
  5. Biopharmaceuticals
  6. Toxicology
  7. Medicinal Chemistry
  8. Pharmacogenetics
  9. Pharmaccogenomics
  10. Pharmacoepidemiology
  11. Pharmacoeconomics


What is pharmacodynamics?

The physical effect of a drug or its mechanism of action


What the drug does to you!


What is pharmacokinetics?

The disposition of a drug by the body, its metabolism and removal from the system.


What you do to the drug!


What is a drug?

A molecule/chemical that will do something to the physiological system that addresses an imbalance in physiology

Must be a chemical that is not part of a diet



Is herbal medicine a drug? Why?

Herbal medicine is not a drug as thousands of molecules in the solution derived from the plant

Therefore, lots of chemicals present that may help but nobody knows why due to the presence of so many chemicals

Specific drugs can sometimes be identified e.g. Willow Bark contains aspirin which takes away a headache


What are the 2 ways a drug act on the body?

1. Therapy

2. Cure


What is a therapy? Example.

A drug which treats causes of a condition but does not rectify the underlying physiological cause. 

E.g. Atenolol treatment for hypertension

E.g. Cetirizine hydrochloride as an antihistamine



What is a cure? Example.

A drug which removes the underlying physiological cause of a condition.

E.g. antibiotic treats bacterial infections

E.g. antifungal treats fungal infections


Importance between therapy and cure medication?

Important in production of drugs:

Cures = less profitable as you only use it once

Therapies = people will continue to use it as it does not take the condition away


What are the methods in which drugs can be named?

1. Chemical

E.g. 2-(4-(2-methylpropyl)phenyl)propanoic acid

2. Generic (no capital)

E.g. ibuprofen

3. Brand name

E.g. nurofen, Calprofen



What name should you use when talking about drugs?

Generic name with NO CAPITAL LETTER


How do we make drugs? 

1. Identify the condition

2. Indentify the pathophysiology that is causing the condition

3.  Identify receptors involved in the pathophysiology, that can be bound to to effect change 

4. Using a compound library, trial-and-error different compounds and observe the effect on the receptor


Where do drugs come from?

1. Assessment of target expression - determine target localisation, determine target quantification


2. Lead compound optimization - characterization of disease phenotypes, efficacy of compound


3. Pre-phase I studies - microdosing, pharmacokinetics

Used to check if the compound has nasty side effects, using animal subjects


4. Clinical Phases I-III


5. FDA approval




What are the features of clinical trials?

Phase 1 :

  • assess the safety of a drug or device - effects including how it is absorbed, metabolized, and excreted, side effects
  • small number of healthy volunteers (20 to 100)

Phase 2:

  • test the efficacy of a drug - elative safety and effectiveness of the new drug
  • involves up to several hundred patients
  • randomized trials where one group of patients receives the experimental drug, while a second "control" group receives a standard treatment or placebo.
  • "blinded trials"

Phase 3:

  • studies involve randomized and blind testing
  • several hundred to several thousand patients.
  • effectiveness of the drug or device, the benefits and the range of possible adverse reactions


How do drugs have their effects?

Bind to biological molecules


What are the biological molecules that drugs can bind to?

1. Lipids

2. Nucleic acids

3. Proteins: receptors, enzymes, ion channels, protein carriers (transporters)


Examples of drugs and the biological molecules that they bind to?

Lipids - potential lipoprotein targets in viral infections

Nucleic acids - anti-cancer agents

Receptors - Beta-adrenoceptors antagonists

Enzymes - angiotensin converting enzyme inhibitors

Protein carriers - selective serotonin reuptake inhibitors


What are the protein biological molecules that drugs effect?

1. Receptors

2. Ion Channels

3. Enymes

4. Protein carriers (transporters)


Types of drugs that effect receptors? How do they have their effect? 

1. Agonist - drug which binds to receptor and activates it

This has an effect on:

  • direct effect - ion channel opning/closing
  • transduction mechanisms - enzyme activation/inhibition, ion channel modulation, DNA transcription

2. Antagonist - drug which binds to receptor but does not activate it, endogenous mediators blocked

This has an effect on:

  • no effect, endogenous mediators blocked


Types of drugs that effect ion channels? How do they have their effect? Example.

1. Blockers - prevents ions passing through channel

Has an effect on: permeation blocked


2. Modulators - binds to protein of receptor and changes the function

Has an effect on: increased of decreased opening probability


E.g. Benzodiazopines


Types of drugs that effect enzymes? How do they have their effect? Example.

1. Inhibitor - binds to enzyme and inhibits it

Has an effect on: normal reaction inhibited

E.g. Captopril - reversible ACE inhibitor

E.g. Aspirin - irreversible COX inhibitor


2. False Substrate - acts as a substrate which competes with endogenous substrate

Has an effect on: abnormal metabolite produced

E.g. Fluorouracil - replaces uracil (anticancer)


3. Prodrug - chemical which is not yet a drug, relies on an enzyme to convert the chemical into the drug of choice

Has an effect on: active drug produced

E.g. L-DOPA - once it has crossed the blood brain barrier, converted to dopamine (cannot cross blood brain barrier on its own, affects the peripheral nervous system not the CNS)


Types of drugs that effect transporters? How do they have their effect? Example.

1. Inhibitor - binds to transporter protein and prevents endogenous substrates passing through

Has an effect on: transport blocked


2. False substrate - binds to transporter protein and prevents endogenous substrates passing through

Has an effect on: abnormal compound accumulated


E.g. almost all drugs bind to transporter proteins


Features of drug binding for agonists?

hydrophobic interaction/hydrogen bond (transient association) between agonist drug and receptor which forms drug-receptor complex and activates receptor



Features of drug binding for antagonists?

Antagonist binds to receptor, forms a drug-receptor complex and eventually dissociates

Stops other things having effect on receptor


What are the 4 types of receptor?

1. Ion channel receptors

2. G protein coupled receptors

3. Enzyme linked receptors

4. Nuclear receptors


What are ion channels receptors? Examples?

Molecule binds to receptor, changes conformation and ions flow through


Nifedipine - calcium channel blocker for hypertension

Nitrazepan - benzodiazopine GABA receptor modulator


What are G protein coupled receptors? Examples?

7 transmembrane domain receptor, can bind to agonist which leads to conformational change of receptor which leads to activation of G-protein within the cell, this activates target enzyme which creates a secondary messenger


Phenylephrine - alpha1 adrenoceptor agonist - decongestant localized vasodilation

Propranolol - beta adrenoreceptor antagonist - tratment of hypertension


What are enzyme linked receptors? Examples?

Agonist binds to receptor, causing two subunits to combine which can lead to phosphorylation cascade (tyrosine kinase linked or tyrosine kinase associated)


Insulin and cytokines as therapy for conditions


What are nuclear receptors? Examples?

Receptor that normally exists in the cytoplasm, bound to a chaperone protein. 

When bound to the agonist, it dissociates from the chaperone proteins and moves into the nucleus. 

Within the nucleus, it can either activate/suppress protein synthesis. 

E.g. steroid hormones and glitazone drugs, e.g. rosiglitazone


Summary of the biological molecules that drugs bind to in order to have their effects?


Important terms in drug binding?

Bmax = binding capacity or total receptor binding - all receptors are bound

Disocciation constant (Kd) = concentration of ligand at 50% of receptor occupany 

Kd = [drug][receptor]


[drug/receptor complex]


What are drug binding curves?


What do drug binding curves tell us?

Affinity of drug to the tissue





What do dose-response curves tell us?

Efficacy of drug




Features of dose response curve?


What is efficacy?

The ability of a drug to elicit a physiological response in the target tissue


How is efficacy measured?

Measured using effective concentration 50 (EC50) = the concentration of drug required to elicit half a maximal response

Lower EC50 = higher efficacy 

Sometimes effective dose concentration (ED50) = the dose of the drug required to elicit half a maximal response


What is the difference between concentration and dose?

Concentration = fixed concentration of drug

Dose = total amount per weight of subject


Define selectivity? How is it measured?

A measure of the ability of a drug to bind at different sites

Measured typically using Kd

smaller Kd = greater selectivity



Define affinity? how is measured?

A measure of the ability of a drug to bind to a specific receptor

Measured using Kd at a specific receptor


What is an agonist?

A drug which has both affinity for the target and efficacy at the target


What is an antagonist?

A drug which has affinity for the target but no efficacy at the target

Will switch off the effect of the agonst


What is a reversible drug?

A drug which binds to the target and changes the function of the target but will also dissociate


What is an irreversible drug?

A drug which binds permantly to the target and changes the function of the target


Features of antagonist binding?


How do antagonist reduce efficacy on a dose response curve?


Features of irreversible competitive antagonists on a dose-response curve?


What is a partial agonist?

A drug which has both affinity and efficacy at the target, but which is incapabe of generating maximum response compared to a full agonist


What is an inverse agonist?

An agent that binds to the same receptor as the agonist but induces a pharmalogical response opposite to that agonist

A neutral antagonist has no activity in the absence of an agonist or inverse agonist but can block the activity of either 


inverse agonist on a concentration-response curve?