Cardiovascular drugs

Question 1

bisoprolol

Answer 1

beta-blocker
Class II anti-dysrhythmic

reduces the positive inotropic and chronotropic effects of sympathetic stimulation on heart. Also AVN blocker.

I: Angina, hypertension, rate control in AF, prevention of sudden cardiac death post-MI or IHD.

SE: bradycardia when given IV. Exercise intolerance.

C/I: ASTHMA. Avoid for hypertension in diabetics

Question 2

disopyramide

Answer 2

Na channel blocker
Class Ia antidysrhythmic

Lengthens AP, forcing slower rate. Prolongs effective refractory period, especially in ischaemic (depolarised) tissue. Thus prevents re-entrant tachycardias. Also suppresses ectopic foci by raising the threshold.

I: prevention and treatment of SV and V tachycardias, including after MI. Maintenance of sinus rhythm after cardioversion.

SE: anticholinergic side effects. Torsades de pointes.

C/I: AF - anticholinergic effect blocks parasympathetic (slowing) influence of vagus on AVN, so can allow atrial tachycardia to penetrate and become ventricular tachycardia.

Question 3

lidocaine (hydrochloride)

Answer 3

Na channel blocker
Ib antidysrrhythmic

Binds more to inactivated channels, so binds more when membrane depolarised (hence more effective in tachyarrhythmias, and in ventricle where AP is the longest). Dissociates within a /normal/ heartbeat, so prevents muscle firing too early.

I: 2nd choice CPR (if amiodarone is not available). Ventricular arrhythmias.

S/E: Convulsions. Torsades de pointes

C/I: Atrioventricular block.

Question 4

propafenone (hydrochloride)

Answer 4

Na channel blocker
1c antidysrrhythmic

Prolongs effective refractory period, especially in ischaemic (depolarised) tissue.

I: Ventricular arrhythmias. Alternative for paroxysmal supraventricular tachyarrhythmias.

SE: dizziness/headache, nausea/vomiting/constipation, anxiety

C/I: recent MI, severe congestive heart failure

Question 5

amiodarone

Answer 5

Na, Ca and K channel blocker. Alpha and beta blocker.
Class III antidysrhythmic

prolongs AP duration and hence effective refractory period, preventing re-entry.

I: CPR. Rhythm-control in AF. It’s an ‘anti-arrhythmic shotgun’, so can be used for anything, particularly when other drugs are ineffective or c/i.

SE: LUNG FIBROSIS, hepatic disorders, hyperthyroidism, nausea, skin reactions (turns blue in sun).

Question 6

flecainide

Answer 6

Na channel blocker
1c antidysrrhythmic

Prolongs effective refractory period, especially in ischaemic (depolarised) tissue. V slow to associate/dissociate, so suppress ectopic beats, but can suppress everything so pro-dysrhythmic.

I: Resistant ventricular tachyarrhythmias. Alternative for paroxysmal AF of recent onset. Wolff-Parkinson-White.

SE: dizziness, fever, oedema, vision disorders

C/I: heart failure, Hx of MI

Question 7

verapamil

Answer 7

L-type calcium blocker. Phenylalkylamine
Class IV antidysrrhythmic

Reduces calcium entry so negative inotropy and chronotropy (L-types are involved in pacemaker currents and phase 0). Bonus vasodilatation. Also AVN blocker

I: Supraventricular arrhythmias, paroxysmal tachyarrhythmias, angina, hypertension

SE: headache/dizziness, flushing/oedema, nausea/vomiting, rash.

C/I: Hx of heart failure (even if controlled, because reduced Ca entry means reduced excitation-contraction coupling). Acute porphyrias, WPW.

Question 8

adenosine

Answer 8

adenosine receptor agonist.

adenosine receptors are present on the AVN, and converge on the ACh pathway, so mimic parasympathetic activation. Hence it causes v brief atrioventricular block

I: diagnosis of broad or narrow complex SVTs (causes paroxysmal SVTs to rapidly return to sinus rhythm).

SE: sense of impending doom

C/I: asthma, COPD, decompensated heart failure, long QT syndrome, severe hypotension.

Question 9

digoxin

Answer 9

cardiac glycoside

Blocks Na/K ATP-ase, which is coupled to Na/Ca exchanger, so increases Ca in the cell. Positive inotrope. Also increases vagal input (we don’t know how), so negative chronotrope and reduces AVN conduction

I: heart failure, rhythm control in AF (only give to sedentary patients)

SE: cerebral impairment, vision disorders. Nausea/vomiting/diarrhoea. Eosinophilia.

C/I: VT or VFib, WPW, second-degree AV block, myocarditis

CANNOT TAKE WITH THIAZIDES

Question 10

diltiazem

Answer 10

L-type Ca channel blocker. Benzothiazepine
Class IV antidysrrhythmic

prevent calcium entry, so negative inotrope and chronotrope. Bonus vasodilatation. AVN blocker.

I: angina, mild hypertension. Also chronic anal fissure (!)

SE: dizziness/headache, flushing/oedema, nausea/vomiting, rash

C/I: AV block, severe bradycardia, acute porphyrias, severe heart failure.
{{i.e. not as strong as verapamil}}

Question 11

dobutamine

Answer 11

beta1 agonist, dopamine analogue

positive inotrope more than chronotrope. Can’t be used long-term because compensation occurs.

I: cardiogenic shock, heart failure w/o hypertension

SE: fever, bronchospasm, headache, inflammation, anti-platelet effect, urinary urgency, vasoconstriction

C/I: phaeochromocytoma

Question 12

furosemide

Answer 12

sulfonamide, loop diuretic

Inhibits NKCC2 in ascending limb, so increased Na excretion. Additional venodilatation effect.

I: fluid overload esp pulmonary oedema, resistant hypertension

SE: hypokalaemia, metabolic acidosis, spasms. Note, can exacerbate diabetes and gout.

C/I: anuria, iatrogenic renal failure, severe hypokalaemia/hyponatraemia, comatose from liver failure

Question 13

bendroflumethiazide

Answer 13

thiazide diuretic

Inhibits Na/Cl cotransport in early distal tubule by binding Cl- site. Also vasodilatation

I: fluid overload in mild-moderate heart failure, hypertension (2nd line)

SE: constipation, hypokalaemia, headache, postural hypotension. Exacerbates diabetes.

C/I: Addison’s, hypercalcaemia, hyponatraemia, refractory hypokalaemia, symptomatic hyperuricaemia

Question 14

Amiloride hydrochloride, triamterene

Answer 14

K-sparing diuretics

Mild diuretic on its own, but mainly used instead of a potassium supplement, bc they cause K retention

I: prevention of hypokalaemia with another diuretic

SE: plenty, freq not known

C/I: Addison’s, anuria, hyperkalaemia

DO NOT GIVE WITH ACEIs or AT2R ANTAGONISTS

Question 15

spironolactone

Answer 15

aldosterone competitive antagonist, K-sparing diuretic

Aldosterone is produced under AT2 influence, increases uptake of Na in early distal tubule. Spironolactone stops this.

I: Ascites, nephrotic syndrome, moderate-severe heart failure. Primary hyperaldosteronism (Conn’s) before surgery

SE: plenty, freq not known

C/I: Addison’s, anuria, hyperkalaemia

Question 16

enalapril, lisinopril, ramipril

Answer 16

Angiotensin converting enzyme inhibitors

Prevent conversion of angiotensin I to angiotensin II, thus disrupting the renin-angiotensin system.

I: heart failure (usually combined with beta-blocker), hypertension (esp young Caucasians), diabetic nephropathy

SE: nephrotoxicity, dry cough, angioedema (esp Afro-Caribbean patients), taste altered

C/I: bilateral renal artery stenosis. don’t combine with aliskiren in CKD2 onwards or diabetes

Question 17

losartan

Answer 17

AT2R (angiotensin II receptor) inhibitor specific for AT1

Angiotensin II acts on AT1 receptors to cause aldosterone release, increase thirst and vasoconstrict. Losartan antagonises this.

I: diabetic nephropathy, heart failure if ACEi is contraindicated, hypertension

SE: nephrotoxicity, postural hypotension, hyperkalaemia, vertigo, back pain, cough

C/I: don’t combine with aliskiren in CKD2 onwards or diabetes

Question 18

aliskiren

Answer 18

renin inhibitor

prevents renin converting angiotensinogen to angiotensin I

I: essential hypertension

SE: arthralgia, diarrhoea, dizziness, electrolyte imbalance

C/I: angioedema, don’t combine with ACEi or AT2R antagonist in patients with eGFR<60 or diabetes

Question 19

glyceryl trinitrate

Answer 19

NO donator

Vasodilates acutely, and reduces venous return.

I: prophylaxis and treatment of angina

SE: cerebral ischaemia, flushing/hypotension, headache

C/I: anything that increases pressure in pericardium (tamponade, hypertrophy, pericarditis), aortic or mitral stenosis, hypotension, raised ICP

Question 20

atorvastatin

Answer 20

Statin

Inhibits HMG-CoA reductase, the rate-limiting enzyme for cholesterol synthesis, so more LDL cholesterol must be taken up from blood to supply cellular requirements.

I: hypercholesterolaemia or hyperlipidaemia that didn’t respond to diet/lifestyle changes. Primary prevention of MI in patients at high risk, secondary prevention of MI.

SE: nausea/constipation/diarrhoea/flatulence. Rarely rhabdomyolysis (hence AKI) and interstitial lung disease

C/I: active liver disease, pregnancy, caution if eGFR <30

Question 21

nifedipine

Answer 21

DHP L-type Ca channel blocker

Stabilises closed conformation. Vaso-selective

I: hypertension (1st line in afro-caribbean patients, 3rd in all others), angina, Raynaud’s, preventing hiccups in palliative care

SE: peripheral oedema/flushing, headaches/dizziness, tachycardia

C/I: Within 1 months of MI, aortic stenosis, unstable or acute angina

Question 22

warfarin

Answer 22

vitamin K antagonist, anticoagulant

Inhibits synthesis of clotting factors (takes a few days)

I: prophylaxis in prosthetic valve, rheumatic heart disease, AF, TIA. Prophylaxis and treatment of DVT

SE: haemorrhage

C/I: first trimester pregnancy, 48 hours postpartum, haemorrhagic stroke

Dosing complicated bc of interactions with food

Question 23

Heparin (inc LMWH)

Answer 23

anticoagulant

Activates anti-thrombin III, which inhibits all the clotting factors in the intrinsic pathway plus thrombin, so prevents fibrin formation

I: thromboprophylaxis (s/c), PE, DVT

SE: thrombocytopenia, thrombocytosis, skin reactions, haemorrhage

C/I: spinal/epidural anaesthesia, recent eye/NS surgery, major trauma, peptic ulcer, severe hypertension, acute bacterial endocarditis, haemorrhagic disorders, thrombocytopenia

Question 24

dabigatran

Answer 24

anticoagulant, NOAC

thrombin inhibitor

I: Treatment and prophylaxis of DVT and PE. Thromboprophylaxis in AF or following hip/knee replacement.

SE: abnormal hepatic function

C/I: valvular heart disease or prosthetic valve (use warfarin instead). Oesophageal varices, vascular aneurysm, recent peptic ulcer, recent NS/eye surgery, recent intracranial haemorrhage

((note, all NOACs have a lower risk of intracranial haemorrhage cf warfarin for AF. Rivaroxaban is given once daily, dabigatran and apixaban twice))

Question 25

aspirin

Answer 25

antiplatelet

inhibits COX-1 in platelets, so prevents formation of TXA2 (platelet aggregant)

I: Secondary prevention of stroke, MI. Management of unstable angina.

SE: haemorrhage, dyspepsia

C/I: peptic ulcer, bleeding disorders, kids under 16

Question 26

clopidogrel

Answer 26

antiplatelet

P2Y12 inhibitor, prevents platelet aggregation

I: secondary prevention of stroke, MI, as adjunct or 2nd line to aspirin

SE: diarrhoea/GI discomfort, haemorrhage, skin reactions

C/I: active bleeding

Question 27

tranexamic acid

Answer 27

inhibits plasminogen activator, so prevents clot lysis

I: menorrhagia, angioedema, epistaxis, prophylaxis of haemorrhage in surgery, treatment and prophylaxis of major haemorrhage following trauma.

SE: diarrhoea/nausea/vomiting

C/I: thromboembolic disease, history of convulsions, fibrinolytic conditions e.g following disseminated intravascular coagulation