ELM 6.1

Question 1

calcium channel blockers do what summary

Answer 1

reduce the opening of l-type calcium channels
target organs (vasculature (and heart))
vessels - inhibit Ca2+ entry
heart - reduced contractility and A-V conduction
side effects - headache, constipation

Question 2

what suffix do ACE inhibitors have?

Answer 2

-pril

Question 3

what suffix do ATII antagonists have?

Answer 3

-artan

Question 4

what suffix do Ca2+ blockers (DHP) have?

Answer 4

-dipine

Question 5

what suffix do beta blockers have?

Answer 5

-olol

Question 6

what suffix do alpha blockers have?

Answer 6

-zosin

Question 7

Which drug is a dihydropyridine calcium channel blocker?

Answer 7

Nifedipine

Question 8

α1 adrenoceptor activation results in constriction of smooth muscle in resistance arterioles. What is the first smooth muscle ion channel to be activated in the contraction process?

Answer 8

IP3 receptor :
IP3 is generated by PLC, which is activated by the alpha1 receptor. It diffuses to the sarcoplasmic reticulum where it activates the IP3 receptor - which is a calcium channel. The calcium that leaves the SR activates the calcium gated chloride channel, and this depolarises the cell, activating the L type channel.

Question 9

Which calcium channel subunits contributes to a channel that is blocked by amlodipine?

Answer 9

Cav 1.1
Cav 1.1-1.4 found in L type channels which are the targets for dihydropyridines - such as amlodipine

Question 10

Patients taking angiotensin converting enzyme (ACE) inhibitors often experience the following unwanted effect

Answer 10

dry cough
ACE cleaves angiotensin I to angiotensin II but is also responsible for the breakdown of bradykinin meaning that ACE inhibitors (e.g. captopril) cause elevated levels of bradykinin - this leads to persistant cough as a side effect

Question 11

Other unwanted side effects of ACE inhibitors include:

Answer 11

HYPERkalaemia, TACHYcardia, and postural HYPOtension

Question 12

Which drug is an angiotensin II type 1 receptor blocker? (ARB)?

Answer 12

candesartan

Question 13

L-type - where is it found and what is it an ideal target for?

Answer 13

cardiac muscle and vascular smooth muscle

Question 14

How is a resistance arteriole classified? (muscle)

Answer 14

smooth muscle around the outside

Question 15

How is a resistance arteriole characterized? (muscle)

Answer 15

smooth muscle around the outside

Question 16

blood pressure is reliant on what two factors?

Answer 16

peripheral resistance and cardiac output

Question 17

Useful drug name hints

Answer 17

ACE inhibitors - pril
ATII antagonists - artan
Ca2+ blockers - dipine
Beta blockers - olol
Alpha blockers - zosin

Question 18

Which of the following calcium channel subunits contribute to a channel that is blocked by amlodipine?

Cav 1.1
Cav 2.1
Cav 2.2
Cav 3.1

Answer 18

Cav 1.1 - Cav 1.1-1.4 are found in L type channels, which are the targets for dihydropyridines such as amlodipine. The other options code for P/Q, N or T type channels

Question 19

α1 adrenoceptor activation results in constriction of smooth muscle in resistance arterioles. What is the first smooth muscle ion channel to be activated in the contraction process?

Calcium activated chloride channel
IP3 receptor
L-type calcium channel
Voltage gated sodium channels

Answer 19

IP3 receptor
IP3 is generated by PLC, which is activated by the alpha1 receptor. It diffuses to the sarcoplasmic reticulum where it activates the IP3 receptor - which is a calcium channel. The calcium that leaves the SR activates the calcium gated chloride channel, and this depolarizes the cell, activating the L type channel.

Question 20

Which of the following drugs is a dihydropyridine calcium channel blocker?
Diltiazem
Lisinopril
Nifedipine
Verapamil

Answer 20

Nifedipine - the ‘pine’ ending

Question 21

Patients taking angiotensin converting enzyme (ACE) inhibitors often experience the following unwanted effect:

Answer 21

Dry cough
ACE is angiotensin converting enzyme. ACE cleaves angiotensin I to angiotensin II but is also responsible for the breakdown of bradykinin, meaning that ACE inhibitors e.g. captopril cause elevated levels of bradykinin. This leads to a persistant cough as a side effect. Other unwanted effects of ACE inhibitors include HYPERkalaemia, TACHYcardia and postural HYPOtension.

Question 22

Which of the following drugs is an angiotensin II type 1 receptor blocker (ARB)?

Answer 22

candesartan

Question 23

Which of the following drugs is a thiazide-like diuretic:
- amiloride
- chlortalidone
- frusemide
- spironolactone

Answer 23

Chlortalidone
Chlortalidone is a thiazide like diuretic. It inhibits reabsorption of sodium (Na+) and chloride (Cl−) ions from the distal convoluted tubules in the kidneys.

Question 24

Select the most powerful diuretic from the list below:
- amiloride
- chlortalidone
- frusemide
- spironolactone

Answer 24

Frusemide
The most powerful class of diuretics are the loop diuretics e.g. frusemide. They are also known as “high ceiling diuretics” and can increase urine output to up to 10 litres per day.

Question 25

An antihypertensive drug that acts at the distal convoluted tubule in the kidney is: - amiloride - bendroflumethiazide - bumetanide - frusemide

Answer 25

bendroflumethiazide Bendroflumethiazide is a thiazide like diuretic. It inhibits reabsorption of sodium (Na+) and chloride (Cl−) ions from the distal convoluted tubules in the kidneys.

Question 26

Which of the following drugs is a competitive antagonist at mineralocorticoid receptors? - amiloride - chlortalidone - frusemide - spironolactone

Answer 26

spironolactone Spironolactone competes with aldosterone for the mineralocorticoid receptor. It is used as a potassium sparing diuretic and in conditions where too much aldosterone is present in the circulation

Question 27

What is so special about phenoxybenzamine?

Answer 27

What is so special about phenoxybenzamine? Phenoxybenzamine (PBZ) is an IRREVERSIBLE blocker of alpha adrenoceptors. It only has one use- in patients who have phaeochromocytomas (adrenaline secreting tumours of the adrenal medulla). During surgery to remove these tumours, a large amount of adrenaline can be released into the circulation, which is very dangerous. If the patient has been given PBZ, it will block their alpha receptors and as the block is irreversible, it cannot be overcome by competition. This can prevent a potentially dangerous rise in blood pressure.

Question 28

David is a professional musician. He has recently been diagnosed with type 2 diabetes. Unknown to his doctor he frequently takes beta blockers to help with stage fright. Misusing beta blockers in this way will cause adverse affects because: a. people with diabetes frequently have very low blood pressure b. beta blockers increase production of insulin c. beta blockers reduce sensitivity to insulin d. diabetes increases the risk of becoming allergic to beta blockers

Answer 28

c People with type II diabetes have tissue insensitivity to insulin and beta cells that do not produce enough insulin. Beta blockers make this worse by decreasing sensitivity to insulin.

Question 29

Reynaud's phenomenon can be precipitated by which class of antihypertensive drugs? a. ACE inhibitors b. ARBs c. Alpha blockers d. Beta blockers

Answer 29

d Non-selective beta blockers such as propranolol can cause peripheral vasoconstriction (vasospasm) due to actions at beta 2 adrenoceptors. This can lead to Raynaud's phenomenon, resulting in cold, numb and discoloured fingers and toes (see picture). All of the other drugs mentioned cause vasodilation so do not precipitate Raynaud's phenomenon but rather, can be used to treat it!

Question 30

In this type of question, two statements are given (X and Y). You must decide if each of these statements is true and, if both are true, whether X is the reason for Y. Statement X: Compared with propranolol, atenolol is more lipid soluble Statement Y: Atenolol is more likely to cause vivid dreams than propranolol a. Statement X is false; statement Y is false b. Statement X is false; statement Y is true c. Statement X is true; statement Y is false d. Statement X is true; statement Y is true AND X is NOT the reason for Y e. Statement X is true; statement Y is true AND X IS the reason for Y

Answer 30

a Neither of these statements is true. Atenololl has poor lipid solubility compared to propranolol and so does not readily cross the blood brain barrier. Propranolol can cross and can then interact with beta adrenoceptors in the brain to produce vivid dreams.

Question 31

What is so special about phenoxybenzamine?

Answer 31

Phenoxybenzamine (PBZ) is an IRREVERSIBLE blocker of alpha adrenoceptors. It only has one use- in patients who have phaeochromocytomas (adrenaline secreting tumours of the adrenal medulla). During surgery to remove these tumours, a large amount of adrenaline can be released into the circulation, which is very dangerous. If the patient has been given PBZ, it will block their alpha receptors and as the block is irreversible, it cannot be overcome by competition. This can prevent a potentially dangerous rise in blood pressure.

Question 32

David is a professional musician. He has recently been diagnosed with type 2 diabetes. Unknown to his doctor he frequently takes beta blockers to help with stage fright. Misusing beta blockers in this way will cause adverse affects because:

Answer 32

beta blockers reduce sensitivity to insulin People with type II diabetes have tissue insensitivity to insulin and beta cells that do not produce enough insulin. Beta blockers make this worse by decreasing sensitivity to insulin.

Question 33

Reynaud's phenomenon can be precipitated by which class of antihypertensive drugs?

Answer 33

Beta blockers Non-selective beta blockers such as propranolol can cause peripheral vasoconstriction (vasospasm) due to actions at beta 2 adrenoceptors. This can lead to Raynaud's phenomenon, resulting in cold, numb and discoloured fingers and toes (see picture). All of the other drugs mentioned cause vasodilation so do not precipitate Raynaud's phenomenon but rather, can be used to treat it!

Question 34

In this type of question, two statements are given (X and Y). You must decide if each of these statements is true and, if both are true, whether X is the reason for Y. Statement X: Compared with propranolol, atenolol is more lipid soluble Statement Y: Atenolol is more likely to cause vivid dreams than propranolol

Answer 34

Statement X is false; statement Y is false Neither of these statements is true. Atenololl has poor lipid solubility compared to propranolol and so does not readily cross the blood brain barrier. Propranolol can cross and can then interact with beta adrenoceptors in the brain to produce vivid dreams.

Question 35

The following drugs are reversible competitive antagonists of adrenoceptors: [mark all correct answers] a. Atenolol b. Doxazosin c. Phenoxybenzamine d. Propranolol

Answer 35

a. b. d All of these drugs are competitive antagonists except for phenoxybenzamine, which is an irreversible antagonist i.e. covalently modifies the receptor

Question 36

A lipophilic antagonist selective for beta 1 adrenoceptors is likely to produce therapeutic effects or side effects in the following tissues: [mark all correct answers] a. Brain b. Heart c. Kidney d. Skeletal muscle

Answer 36

a, b, c In addition to its well-known role in the heart, the beta 1 adrenoceptor is present in the juxtaglomerular apparatus where it influences renin release and in the brain (vivid dreams caused by metoprolol). In skeletal muscle, however, it is the beta 2 adrenoceptor that is expressed.