ELM 6.1 Flashcards
calcium channel blockers do what summary
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
what suffix do ACE inhibitors have?
-pril
what suffix do ATII antagonists have?
-artan
what suffix do Ca2+ blockers (DHP) have?
-dipine
what suffix do beta blockers have?
-olol
what suffix do alpha blockers have?
-zosin
Which drug is a dihydropyridine calcium channel blocker?
Nifedipine
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?
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.
Which calcium channel subunits contributes to a channel that is blocked by amlodipine?
Cav 1.1
Cav 1.1-1.4 found in L type channels which are the targets for dihydropyridines - such as amlodipine
Patients taking angiotensin converting enzyme (ACE) inhibitors often experience the following unwanted effect
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
Other unwanted side effects of ACE inhibitors include:
HYPERkalaemia, TACHYcardia, and postural HYPOtension
Which drug is an angiotensin II type 1 receptor blocker? (ARB)?
candesartan
L-type - where is it found and what is it an ideal target for?
cardiac muscle and vascular smooth muscle
How is a resistance arteriole classified? (muscle)
smooth muscle around the outside
How is a resistance arteriole characterized? (muscle)
smooth muscle around the outside
blood pressure is reliant on what two factors?
peripheral resistance and cardiac output
Useful drug name hints
ACE inhibitors - pril
ATII antagonists - artan
Ca2+ blockers - dipine
Beta blockers - olol
Alpha blockers - zosin
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
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
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
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.
Which of the following drugs is a dihydropyridine calcium channel blocker?
Diltiazem
Lisinopril
Nifedipine
Verapamil
Nifedipine - the ‘pine’ ending
Patients taking angiotensin converting enzyme (ACE) inhibitors often experience the following unwanted effect:
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.
Which of the following drugs is an angiotensin II type 1 receptor blocker (ARB)?
candesartan
Which of the following drugs is a thiazide-like diuretic:
- amiloride
- chlortalidone
- frusemide
- spironolactone
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.
Select the most powerful diuretic from the list below:
- amiloride
- chlortalidone
- frusemide
- spironolactone
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.
An antihypertensive drug that acts at the distal convoluted tubule in the kidney is:
- amiloride
- bendroflumethiazide
- bumetanide
- frusemide
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.
Which of the following drugs is a competitive antagonist at mineralocorticoid receptors?
- amiloride
- chlortalidone
- frusemide
- spironolactone
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
What is so special about phenoxybenzamine?
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.
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
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.
Reynaud’s phenomenon can be precipitated by which class of antihypertensive drugs?
a. ACE inhibitors b. ARBs c. Alpha blockers d. Beta blockers
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!
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
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.
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.
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:
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.
Reynaud’s phenomenon can be precipitated by which class of antihypertensive drugs?
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!
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
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.
The following drugs are reversible competitive antagonists of adrenoceptors:
[mark all correct answers]
a.
Atenolol
b. Doxazosin c. Phenoxybenzamine d. Propranolol
a. b. d
All of these drugs are competitive antagonists except for phenoxybenzamine, which is an irreversible antagonist i.e. covalently modifies the receptor
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
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.
