Principles of pharacology

Question 1

what are exogenous ligands

Answer 1

pharmaceuticals and non-pharmaceuticals (what you might actually consider a drug)

Question 2

what are endogenous ligands

Answer 2

hormones or neurotransmitters

Question 3

drug receptor interactions

Answer 3

Receptor exist in at two states which are often referred to as a R and R*
A reversible equilibrium exists between the states

Question 4

drug-receptor interactions - agonists

Answer 4

agonist mimic the action of an endogenous ligand

Question 5

drug-receptor interactions - antagonist

Answer 5

antagonist bind to and stabalise R but do not mimic the biological response an endogenous ligand

Question 6

affinity

Answer 6

High affinity - equilibrium favours R*
Lower affinity - equilibrium favours R

Question 7

intrinsic efficacy

Answer 7

to elicit a biological response after binding to a receptor, a drug must have intrinsic efficacy

efficacy defines the size of the biological response that can be initiated when a drug binds to a receptor

Question 8

potency

Answer 8

measurement of how much a drug it takes to elicit a biological response.
- product of affinity and intrinsic efficacy plus the downstream signalling cascade

Question 9

what is the sympathetic and parasympathetic effect and receptors of the pupil

Answer 9

Sympathetic effect : dilation (contracts radial muscle)
receptor: a1
Parasympathetic effect: constriction (contracts sphincter muscle
receptor: M3

Question 10

what is the sympathetic and parasympathetic effect and receptors of the airways

Answer 10

Sympathetic effect : relax
receptor: B2
Parasympathetic effect: contract
receptor: M3

Question 11

what is the sympathetic and parasympathetic effect and receptors of the heart

Answer 11

Sympathetic effect : increase heart rate and force of contraction
receptor: B1
Parasympathetic effect: decrease rate of contraction
receptor: M2

Question 12

what is the sympathetic and parasympathetic effect and receptors of the sweat glands

Answer 12

Sympathetic effect : localised generalised secretion
receptor: a1 and N3

Question 13

where are beta adrenoreceptors present

Answer 13

on the cell surface of cells in the sinoatrial node, atrioventricular node and non-pacemaker cells of the heart

Question 14

what is the effect of B1 adrenoreceptor activation Gas

Answer 14

include increased chronotropy, increased luistropy and increased inotropy

Question 15

what are some indications for use of beta adrenoreceptor blockers include

Answer 15

• Rate control in atrial fibrillation – first-linetreatment (uncomplicated and comorbid withHFpEF)
• Secondary prevention in STEMI
• Management of stable angina – first-linetreatment
• Mitral stenosis – consideration
• HFrEF – first-line treatment
• Supraventricular tachycardia – recommended
• Ectopic beats
• Ventricular tachycardia –with/without an ICD

Question 16

what is sotalol hydrochloride and what is its mechanism of action

Answer 16

used to treat certain types of heart rhythm disorders, particularly atrial fibrillation and ventricular arrhythmias.

mechanism of action: non-selective beta-adrenergic antagonist (beta blocker) with class III antiarrhythmic properties. works by blocking certain beta receptors in the heart leading to reduction in heart rate and the force of contraction.

Question 17

what is pharmacokinetics

Answer 17

it involves the study of how the body interacts with a drug, encompassing its absorption, distribution, metabolism, and excretion (ADME)

Question 18

what are factors influencing absorption

Answer 18

route of administration, drug formulation, physiological factors such as blood flow

Question 18

where is the primary site of drug metabolism

Answer 18

the liver

Question 18

what are factors affecting distribution

Answer 18

blood flow, capillary permeability, drug solubility, presence of binding proteins

Question 18

what are the organs involved in excretion

Answer 18

the kidneys are the primary organs, through urine but the liver (via bile) and other routes such as sweat and saliva also contribute

Question 18

ADME of sotalol

Answer 18

Absorption – Sotalol is almost entirely absorbed (oral) and escapes almost entirely from first-pass metabolism. Bioavailability is 90-100%.
* Distribution – Volume of distribution is 1.2-2.4 l kg-1
* Metabolism – Not metabolised
* Excretion – Renal clearance

Question 18

what is EC50

Answer 18

represents the concentration of an agonist compound where 50% of its maximal agonistic effect is observed

Question 18

what is the ID50

Answer 18

represents the dose required to kill half the members of a tested population after a specific duration of time

Question 19

what is the IC50

Answer 19

represents the concentration of an antagonist compound where 50% of its maximal antagonist effect is observed

Question 19

what is ED50

Answer 19

represents the minimum required dose to show desired activity of drug in half the members of a tested population after a specific duration of time

Question 20

what is the order of drug trials

Answer 20

In vitro studies
Animal trials
Clinical trials

Question 21

what is flecainide acetate

Answer 21

Flecainide acetate is an antiarrhythmic medication used to treat certain types of irregular heartbeats, particularly those arising from the atria (the upper chambers of the heart) and ventricles (the lower chambers of the heart). It belongs to the class Ic antiarrhythmic agents and works by inhibiting sodium channels, which helps stabilize the electrical activity of the heart

Question 22

Flecainide acetate - ADME

Answer 22

• Absorption – Flecainide is almost entirely absorbed (oral) and escapes almost entirely from first-pass metabolism. Bioavailability is 90-95%
• Distribution – Volume of distribution is ~5.5 l kg-1
• Metabolism – CYP2D6* Excretion – Renal clearance
• Excretion – Renal clearance