Drugs

Question 1

Bisphosphonates

Answer 1

Prevent the loss of bone mass, can be used in the treatment of osteoporosis.
Encourage osteoclasts to undergo apoptosis.

Question 2

Succinylcholine

Answer 2

Causes depolarisation block. Opens the AChR but isn’t degraded by AChE. Will inactivate sodium channels. Maintained depolarisation will fail to open adjacent sodium channels because they are inactivated.

In anaesthetics, inhibits acetylcholinesterase and is used to reverse the nicotinic receptor blockade.

Question 3

Procaine/Lidocaine

Both pathways

Answer 3

Local anaesthetic, blocks the pore of sodium channels

Hydrophobic pathway - diffuses into the membrane, then blocks the receptor by moving laterally into it. Non use dependent.

Hydrophilic pathway - diffuses through the membrane and is activated by hydrogen ions. Then moves into the pore and blocks it. Use-dependent.

Question 4

Adrenaline

Answer 4

Used in cardiac arrest to restore function and anaphylaxic shock.
Sympathomimetic

Question 5

Dobutamine

Answer 5

Beta 1 agonist

Given in cardiogenic shock to restore heart function

Question 6

Salbutamol

Answer 6

Beta 2 agonist for the treatment of asthma. Causes bronchodilation.

Question 7

Prazosin

Answer 7

Alpha 1 antagonist.
Antihypertensive.
Inhibits NA action on smooth muscle receptors causing vasodilation.

Question 8

Propanolol

Answer 8

Beta1/2 antagonist.
Slows the heart rate and force of contraction.
Also causes bronchoconstriction.

Question 9

Atenolol

Answer 9

Beta-1 antagonist.
Slows heart rate and force of contraction
Minimal bronchoconstriction

Question 10

Pilocarpine

Answer 10

Muscarinic agonist
Treatment for glaucoma
Causes constriction of pupillary muscles, allowing aqueous humour to drain more quickly

Question 11

Atropine

Answer 11

Muscarinic antagonist.
Increases heart rate and bronchodilation
Used to dilate pupils for examination of the eye

Question 12

Neostigmine/pyridostigmine

Answer 12

Reversible anticholinesterases which are broken down much slower than acetylcholine so have relatively long lasting effects.
Used in treatment of myasthenia gravis, can reverse neuromuscular block.

Question 13

Curare

Answer 13

Acetylcholine receptor antagonist, causes paralysis.

Cure using pyridostigmine.

Question 14

Nifedipine

Answer 14

Dihydropyridine
Blocks L-type calcium channels
Lowers blood pressure and reduces angina.

Question 15

Explain supersensitivity.

Answer 15

Agonist deprivation or antagonist exposure which causes upregulation of receptors.

Question 16

Explain desensitisation.

Answer 16

Method to reduce the responsiveness to the continuing or increasing dose of a drug

Question 17

Explain homologous desensitisation

Answer 17

When a receptor reduces its response to a signalling molecule when that agonist is in high concentration.

Question 18

Explain heterologous desensitisation.

Answer 18

Broad unresponsiveness to a variety of agonists after prolonged stimulation by one agonist.