Drugs - CVS

Question 1

Digoxin

Answer 1

Cardiac glycoside
Inhibiton of Na+/K+ ATPase in myocardium, reversing action of Na+/Ca2+ exchanger, increasing cellular calcium and increasing contractile force of myocardium and lowering HR (lengthens the AP)
Arrhythmia (AF, VTach) and Heart failure
Can cause anorexia, nausea, vomitting, diarrhoea, confusion, drowsiness, atrial tachycardia with AV block

Question 2

Bendroflumethiazide

Answer 2

Thiazide diuretic
Inhibits sodium resorption in DCT via Na-Cl contransporter
Used for Hypertension and oedema related to heart failure
Can cause postural hypotension, hyponatraemia, hypokalaemia, hypercalaemia, gout, impotence, fatigue, pulmonary oedema

Question 3

Furosemide

Answer 3

Benzoic-solfonamide-furan diuretic (loop)
Inhibits sodium-potassium-chloride cotransporter on the thick ascending limb of LoH
Treats hypertension and oedema (often from congestive HF), also used in renal impariment, hepatic cirrhosis and nephrotic syndrome
Is ototoxic, can cause gout (hyperuricaemia), hyperglycaemia, hypokalaemia

Question 4

Amiloride

Answer 4

K+ Sparing Diuretic
Blocks ENaC in late DCT and CD
Treats hypertension and congestive HF
Can cause hyperkalaemia

Question 5

Spironolactone

Answer 5

Aldosterone inhibitor (diuretic)
Blocks androgen receptor
Used to treat oedema in HF (congestive) and hypertension and hypokalaemia, nephrotic syndrome and ascites as well as Conn’s syndrome and secondary hyperaldosteronism (E.g. hepatic cirrhosis)
Can cause increased frequency, ataxia, drowsiness, rashes, feminization (in males) and hyperkalaemia

Question 6

Adenosine

Answer 6

Purine nucleoside (anti-arrhythmic)
Agonist for adenosine receptors, blocks transmission at AV node and vasodilates
Treats Re-entry arrhythmias (Reentrant tachycardia, AV nodal reentrant tachycardia) Atrial tachycardia and AF, VTach
Can cause Rash, sweating, facial flushing, sense of impending doom

Question 7

Amiodarone

Answer 7

Class III anti-arrhythmic
Prolongs phase 3 of cardiac AP (repolarisation phase) via inhibition of Na,K-activated myocardial adenosine triphosphatase and also acts as a beta blocker and calcium channel blocker thus causing decrease HR and vascular resistance
Treats Tachyarrhythmias (Ventricular and supraventricular (atrial)) and other arrhythmias (VF, AF)
Contraindicated by pregnancy (expressed in milk), those with AV block or sinus nodal bradycardia or heartblock)

Question 8

Lidocaine

Answer 8

Class 1b anti-arrhythmic
Blocks fast voltage gated Na+ channels, blocking depolarisation and AP transmission (also mechanism of its local anaesthesia)
Used to treat ventricular tachycardia and as a local anaesthetic
Can cause CNS excitation (nervousness, agitation, tremor, psychosis) or depression (Drowsiness, venous insufficiency, confusion, resp depression) as well as cardiovascular side effects (hypotension, bradycardia, arrhythmias, cardiac arrest, oedema)

Question 9

Atenolol

Answer 9

Beta 1 andrenoceptor antagonist (Beta blocker)
Negative chronotropic effect on heart (reduced HR) via reduction in sympathetic stimulation
Treats hypertension, angina, long QT, acute MI, Supraventricular tachycardia, VTach
Can cause bradycardia, dizziness, confusion, fainting

Question 10

Propranolol

Answer 10

Non-selective Beta blocker (B1 and B2)
Slows HR and lowers contractile force of heart
Treats hypertension, dysrhythmias, angina and supportive treatment in MI
Can cause Bradycardia, hypotension, HF, heart block, bronchospasm, dyspnoea

Question 11

Doxazosin

Answer 11

Alpha 1 selective andrenoceptor antagonist
Alpha 1 receptors mediate contraction and hypertrophic growth of smooth muscle cells, antagonism leads to smooth muscle relaxation in peripheral vasculature (and prostate)
Treats hypertension and benign prostatic hypertrophy
Can cause hypotension

Question 12

Ramipril

Answer 12

ACEI
Inhibits ACE, less formation of ATII which leads to reduced arteriole smooth muscle contraction, less aldosterone secretion, less sympathetic stimulation and less ADH release from the pituitary. This lead to reduced BP via reduction in TPR and plasma volume
Used to treat hypertension (first line) and congestive HF
Can cause chronic cough (less breakdown of Bradykinin) dizziness, hypotension, fainting,

Question 13

Losartan

Answer 13

Angiotensin II type 1 receptor blocker (AT1 receptor)
Works on the end organs of the RAAS system by reducing arteriole smooth muscle contraction, less aldosterone secretion, less sympathetic stimulation and less ADH release from the pituitary. This lead to reduced BP via reduction in TPR and plasma volume
Used to treat hypertension
Can lead to URTIs, stuffy nose, dizziness, hypotension (NO COUGH)

Question 14

GTN Spray

Answer 14

Nitrovasodilator
Donates NO, stimulating guanylate cyclase in smooth muscle cells of blood vessels, increased production of cGMP occurs and the downstream effect of this is reduced Ca2+ in cells, leading to relaxation
Used to treat angina and supportive treatment or prevention in MI
Adverse effects are hypotension, dizziness, headache, syncope

Question 15

Isosorbide Mononitrate

Answer 15

Nitrate
Donates NO, stimulating guanylate cyclase in smooth muscle cells of blood vessels, increased production of cGMP occurs and the downstream effect of this is reduced Ca2+ in cells, leading to relaxation
Used to treat angina and prevention of MI
Adverse effects include Headache, sleep disturbances, hypotension

Question 16

Amlodipine

Answer 16

Dihydropyridine type Calcium channel blocker
Stabilises L-type voltage gated Ca2+ channels in vascular and myocardial smooth muscle. Inhibits Ca2+ influx into cells leading to vasodilation
Treats hypertension, angina, Coronary artery disease
ADRs: Peripher oedema, dizziness, palpitations, fatigue

Question 17

Verapamil

Answer 17

L-type calcium channel blocker
Class IV anti-arrhythmic that blocks voltage gated Ca2+ channels, reducing impulse conduction through the AV node and contraction of vasculature
Treats hypertension, angina, arrhythmia
ADRs: constipation, dizziness, hypotension, headache

Question 18

Warfarin

Answer 18

Anti-coagulant
Inhibits Vit K dependent synthesis of clotting factors II, VII, IX, X as well as protein C, protein S and protein Z. This reduces the coagulability of the blood preventing thrombosis or embolism
Prophylaxis in those at risk of a primary or secondary thrombosis as well as reducing risk of embolism
ADRs: Haemorrhage (stroke)

Question 19

Heparin

Answer 19

Anti-coagulant
Heparin binds to the enzyme inhibitor antithrombin II (ATII) which then binds to and inactivates thrombin and other proteases involved in clotting
Treats: those at increased risk of thrombosis or embolism or to reduce risk of adverse event in those with established thrombosis. (E.g. Acute coronary syndrome/NSTEMI, AF, DVT, PE
ADRs: Haemorrhage, thrombocytopenia, hyperkalaemia (aldosterone suppression)

Question 20

Protamine sulphate

Answer 20

Anti-Heparin
Cationic peptide that binds to heparin to form a stable ion pair, inactivating heparin
Used post surgery to reverse heparin anticoagulation or after heparin overdose
ADRs: Allergic reactions (derived from fish)

Question 21

Aspirin

Answer 21

NSAID, Anti-platelet
Inhibits COX, reducing Prostaglandin and thromboxane A2 production and hence reducing inflammation and inhibiting platelet aggregation
Used to treat Pain, fever, inflammation and is used preventatively in those at high risk of heart attacks and strokes as well as pot-surgery
ADRs: Peptic ulcer, increased incidence of haemorrhagic stroke, haemorrhage

Question 22

Dipyridamole

Answer 22

Phosphodiesterase inhibitor (anti-coagulant)
Inihibits adenosine deaminase and phosphodiesterase, preventing degradation of cAMP, and inhibitor of platelet function by reducing thromboxane A2 activity. Also directly stimulates release of prostacyclin, inducing adenylate cyclase activity within platelets, raising cAMP conc in platelets,. further reducing activity of platelets
Used for inhibiting clot formation
ADRs: hypotension, haemorrhage

Question 23

Clopidigrel

Answer 23

Thienopyridine class anti-platelet
Inhibits ADP receptor on platelets cell membranes, reducing their activation and cross linking by fibrin
Can inhibit blood clots that might form as a result of CAD, peripheral vascular disease, and prevent MI and stroke
ADRs: Thrombotic thrombocytopenic purpura, Haemorrhage

Question 24

Alteplas/Reteplase

Answer 24

Trade name of t-PA
Catalyses the conversion of plasminogen to plasmin, resulting in clot breakdown
Used in PE, MI, Thrombo-embolic stroke
STRONGLY CONTRAINDICATED BY HAEMORRHAGIC STROKE
ADRs: Haemorrhage, stroke

Question 25

Simvastatin

Answer 25

Lipid-lowering Statin
Inhibit HMG-CoA reductase, the rate limiting enzyme of cholesterol’s metabolic pathway, reducing cholesterol production
Primarily used to treat dyslipidaemia (Hypercholesterolaemia), prevention of heart issues
ADRs: Joint pain, muscle cramps, rhabdomyolysis

Question 26

Bezafibrate

Answer 26

Fibrate (lipid lowering)
Stimulates HDL, reduces LDL, reduces cholesterol synthesis via agonism of PPAR-alpha
Used to treat combined hyperlipidaemia
ADRs: Hepatotoxicity, myopathy, rhabdomyolysis

Question 27

Ezetimibe

Answer 27

Lipid-lowering drug
Decreases cholesterol absorption in the small intestine and the amount of cholesterol available to liver, forcing it to absorb more from circulation
Uses: Second line treatment for hypercholesterolaemia
ADRs: Haedache, diarrhoea (steatorrhoea)