Cardiovascular drugs

Anti-platelet

• Aspirin - prevents production of thromboxane A2 inhibiting platelet aggregation. Used in low doses (75mg/day PO) for secondary prevention following myocardial infarction, Transient Ischemic Attack and Stroke. Also used for patients with Angina or peripheral vascular disease. Also an NSAID and may worsen GI symptoms.
• P2Y12 antagonists - (Clopidogrel, pasugrel, ticagrelor) also block platelet aggregation but cause less gastric irritation. Used with Aspirin after PCI, and in Acute Coronary Syndrome

Anticoagulants

• DOACs - Xa inhibitors (apixaban), direct thrombin inhibitors (dabigatran) for treatment of Atrial Fibrillation and clots.
• Warfarin is still used for people with mechanical heart valves
• Anticoagulants used in Acute Coronary Syndrome include LMWH, fondaparinux (Xa inhibitor) & bivalirudin (thrombin inhibitor)

$\beta$ blockers

• Antagonise the sympathetic nervous system
• Blocking ${\beta }_1$ is negatively inotropic and chronotropic
• Blocking ${\beta }_2$ induces peripheral vasoconstriction and bronchoconstriction
• Propanolol is non selective, bisoprolol is ${\beta }_1$ selective
• Used in Angina, hypertension, post myocardial infarction, Heart Failure
• Contraindicated in severe asthma/COPD, Heart Block

ACEi

• Causes vasodilation and excretion of sodium and water. eg Ramipril
• Used in hypertension, Heart Failure, post myocardial infarction
• Can cause Hyperkalaemia
• Put pressure on the kidneys so hold in Acute Kidney Injury and monitor U&Es for kidney function
• Can cause a dry cough so may switch to ARB (ARB contraindicated in Pregnancy however)

Diuretics

• Loop diuretics - eg Furosemide inhibit NA/2Cl/K co-transporter. $\downarrow$ Na${}^{+}$ $\downarrow$ K${}^{+}$ $\downarrow$ Ca${}^{2+}$. Heart Failure
• Thiazide/thiazide-like diuretics are used in hypertension (indapamide) and Heart Failure (metolazone). $\downarrow$ K${}^{+}$ $\uparrow$ Ca${}^{2+}$ $\downarrow$ Mg${}^{2+}$, $\uparrow$ urate ($\pm$ gout).
• Potassium sparing diruetics - aldosterone antagonists (spironolactone, eplerenone)

Vasodilators

• Used in Heart Failure, Ischemic Heart Disease,
• Nitrates - preferentially dilate veins and large arteries. $\downarrow$ preload (filling pressure)
• Hydralazine - primarily dilate resistance vessels $\downarrow$ after-load (BP)
• Prazosin - $\alpha$-blocker dilates veins and arteries

Calcium antagonists

• $\downarrow$ cell entry of Ca${}^{2+}$ in smooth muscle, promoting coronary and peripheral vasodilation and reducing myocardial Oxygen use. All current drugs block L-type Ca${}^{2+}$ channels but different binding properties cause different effects. hypertension and Angina
• Dihydropyridines - eg amlodipine are mainly peripheral vasodilators and cause a reflex tachycardia so used with a $\beta$-blocker
• Non-dihydropyridines - eg verapamil and diltiazem slow conduction at the AV and SV node and may be used to treat dysrhythmias in addition.

Don't give non-dihydropyridines with $\beta$-blockers for risk of severe bradycardia

Digoxin

• Blocks the Na+/K+ pump. Used to rate control in fast AF (aim for less than 100)
• Weak +ve inotrope, half life of 36 hours
• $\uparrow$ Toxicity risk if $\downarrow$ K${}^{+}$ $\downarrow$ Mg${}^{2+}$ or $\uparrow$ Ca${}^{2+}$
• May caused ST Depression in toxicity Digoxin effect

Sodium channel blockers

• Class I anti-arrhythmics
• Procainamide (1a) and Lidocaine (1b) can be used to terminate VT
• Flecainide (1c) is useful for Atrial Fibrillation cardioversion and for anti-arrhythmia prophylaxis
• Contraindicated in Heart Failure, Ischemic Heart Disease, Heart Block, and valve disease

Amiodarone

• Class III anti-arrhythmic
• Prolongs cardiac action potential reducing the chance for tacharrythmias
• Used in SVT and VT
• Broad side effects - thyroid disease, liver disease, Pulmonary Fibrosis and peripheral neuropathy
• Monitor TFTs and LFTs every 6 months

Ivabradine

• Blocks the pacemaker funny current (small current to give the heart a push to make a contraction). So slows pulse rate without significantly dropping blood pressure
• Angina, Heart Failure and off licence in autonomic tachycardia syndromes
• CI in acute myocardial infarction, long QT, bradycardia.
• Many drug interactions including with calcium antagonists

Statins

• Inhibit HMG-CoA reductase preventing de novo synthesis of cholesterol in the liver. This increases LDL receptor expression on hepatocytes leading to $\downarrow$ LDL cholesterol.
• More effective if given at night
• Generally v well tolerated