Intro to Pharmacology

Question 1

what is the difference between a medicine + a drug (definitions)

Answer 1

Medicine= preparation that contains 1 or more than drugs plus excipients (i.e., solvent, stabilisers, fillers, colouring agents, flavourings, etc.) used to treat/cure/prevent disease

drug= chemical substance of known structure which, when administered to living organism, produces a biological effect (i.e .binds to regulatory molecules + activates/inhibits normal body processes)

Question 2

define pharmacology

Answer 2

Pharmacology= study of drug characteristics: mechanism of action, effects they have, effects, dosage, usage

Question 3

define pharmacy

Answer 3

Pharmacy= profession of preparation/ supply of medicine

Question 4

define clinical pharmacology

Answer 4

Clinical pharmacology= scientific study of drug effects in humans

Question 5

define therapeutics

Answer 5

Therapeutics= branch of medicine concerned with the treatment of disease

Question 6

define toxicology

Answer 6

Toxicology= study of undesirable effects of chemical agents (poisons) on living systems. Also includes actions of industrial pollutants, natural organic and inorganic poisons + other chemicals on ecosystems/species.

Question 7

define drug receptor

Answer 7

DRUG RECEPTOR : The molecular components of the body with which a drug interacts to bring about its effects.
Receptors are generally proteins located on cell outer membranes although other non-protein drug targets exist. They’re targets for drug molecules. Each receptor is specific for a particular drug.
E.g. brain contains:
Cannabis receptors specific for cannabis and morphine receptors for morphine. Morphine will not target cannabis receptors and vice versa. Both receptors are found on the cells of the brain. It is this targeting or specificity which makes drugs function.

Question 8

define pharmacodynamics

Answer 8

Pharmacodynamics
= what drug does to the body
*biochem + physiologic effects of drugs
* drugs interact w receptors
* they bind to + alter the function of that receptor

Question 9

define agonist

Answer 9

Agonists
=bind to receptors/activates them (mimic natural ligand of receptor)
*When ligand leaves the receptor, usually deactivates receptor + stops the effect
*Some receptors are permanently activated even after ligand has left - covalent change in receptor

Question 10

define partial agonists

Answer 10

Partial agonists
=bind to receptor at active site
*Lower affinity to the receptor and do not bind as strongly as a full agonist
*Unable to cause the maximal response even if all receptors are occupied
*Prevent other agonists from binding

Question 11

define antagonist

Answer 11

Antagonists
= binds to a receptor + prevents activation of receptor

Question 12

what are the 2 types of drug interactions

Answer 12

allosteric + competitive

Question 13

what do we mean by a competitive interaction in pharmacology

Answer 13

a specific type of interaction between a drug and its target in which the drug competes with another substance for binding to the same site on the target molecule.
*involves agonists + antagonists
*effects potency + efficacy of drug

Question 14

describe the difference between agonist + antagonist

Answer 14

Agonists bind to receptors/activates them (mimic natural ligand of receptor)
{drugs with both affinity (they bind to the target receptor) and intrinsic efficacy (they change receptor activity to produce a response).}

Antagonists bind to the target receptor but do not produce a response {i.e. have affinity but zero intrinsic efficacy; therefore they]

Question 15

what do we mean by affinity of drug

Answer 15

affinity (they bind to the target receptor)

Question 16

what do we mean by intrinsic efficacy of drug

Answer 16

intrinsic efficacy (they change receptor activity to produce a response).

Question 17

what do we mean by allosteric interactions

Answer 17

Allosteric interactions:
*Do not act directly on the receptor
*Affect the efficacy or binding affinity
–>Allosteric activators (increase the activation of the receptor)
–>Allosteric inhibitors (decrease the activity of the receptor)

Question 18

what are the 2 types of antagonist

Answer 18

Competitive antagonist
-Fits into the active site but does not activate receptor and competes for binding site
Reduce agonist potency
-Reversable binding
-Need to add more drug to get to EC50

Non-competitive antagonist
-Binds to a site that is not agonist binding active site
-Modulates function of receptor
-Reduce agonist efficacy
-Irreversible (covalent) binding
-Maximal effect reduced
-EC50 is same dose as for agonist alone

Question 19

define chemical antagonist

Answer 19

Chemical antagonist= binds directly to an agonist preventing it binding to receptor or substrate (heparin & protamine)

Question 20

define physiologic antagonist

Answer 20

Physiologic antagonist= 2 drugs have exactly opposite actions via different pathways

Question 21

what is an inverse agonist, give an example

Answer 21

inverse agonist= a type of ligand that binds to the same receptor binding site as an agonist but induces the opposite pharmacological response compared to the agonist

N.b. like nalaxone (to save patient) –Suppressing basal MU-opioid receptors signalling, complete reversal of opioid drug effects, including respiratory depression

Not only antagonise effects of an agonist, but exert opposite effect by suppressing spontaneous receptor signalling (when present) – Negative efficacy

Only seen in systems that are constitutively active without any binding of ligand/agonist

Decreases the activity below the basal level.

Question 22

What is pharmacokinetics

Answer 22

Pharmacokinetics
=what body does to the drug

• Liberation: way that a drug is released from its administered form
• Absorption: how a drug travels from site of administration to site of action.
• Distribution: passage of a drug through bloodstream to different tissues in body.
• Metabolism: enzymatic activities that break down a drug

*Excretion: elimination of a drug from body.

Question 23

what is Pharmacogenomics

Answer 23

Pharmacogenomics
* refers to genetic variability [how our individual genetic make up influences our responses to certain drugs]

*Causing variations in delivery of drug to or removal of drug from sites of action in individuals (involved in efficacy and/or toxicity)

*Problematic for drugs with a narrow therapeutic range or therapeutic. Because small differences may result in therapeutic failure or toxicity
e.g. succinylcholine, Caucasians have enzyme 1,000 fold reduced affinity. So drug has slower elimination

Question 24

what are 3 pharmaceutical formulation types

Answer 24

*Solid Dosage forms
*Semi-Solid Dosage Forms
*Liquid Dosage Form

Question 25

what is molecular mass + what unit do we use to measure this, why is this important to undertstand?

Answer 25

The molecular mass is the mass of a given molecule, for which the unit Dalton (Da) is used.

small molecules (small molec mass) diffuse rapidly across cell membranes and reach intracellular sites of action

Question 26

what are the drug-receptor bonds (strongest to weakest)

Answer 26

Drugs bind to receptors with a variety of chemical bonds

-Very strong covalent (irreversible action)
-Weaker ionic or electrostatic (between cation + anion)
-Very weak interactions (hydrogen, van der Waals + hydrophobic)

Question 27

Ka is an indicator of__________

Answer 27

Ka is an indicator of acidity of the drug

Question 28

what do we mean by weak acid

Answer 28

Weak means incomplete dissociation in water

Question 29

The lower the pKa–> the ______acidity of acid/ stronger the acid

Answer 29

The lower the pKa–> the HIGHER acidity of acid/ stronger the acid

Question 30

what do we mean by specificity when talking about drugs

Answer 30

Specificity =Ability of a drug to bind with one receptor
No drug is truly specific
But many have relative selective action on one type of receptor

Question 31

what do we mean by selectivity when talking about drugs

Answer 31

Selectivity= Ability of the drug to preferentially produce a specific effect
The vast majority of drugs are selective rather than specific
Affected by:
Physiochemical properties of the
Special features of the recipient, such as genetic make-up, sex, age, and co-existing disease
The dose given and the route by which it is administered

Question 32

3 drug naming categories

Answer 32

->Chemical Name (i.e., IUPAC name)
->Generic Name (might be a shorthand version of drug’s chemical name, structure, or formula)
->Trade Name (capitalised):
Drugs can be sold under trade names rather than as generic preparations - cost of developing a drug, testing it through preclinical + clinical trials & bringing it to market is very expensive - protecting production of the drug for the first few years of its use

Question 33

4 ways we classify drugs

Answer 33

*Therapeutic classification
*Pharmacologic classification (based on mechanism of action)
*Chemical classification
*Legal classification (controlled substances, drug schedules)