Drug Therapies Flashcards

1
Q

Mechanism of action: antiplatelet agents

A

-Cyclo-oxygenase inhibition (Aspirin)
-P2Y12 inhibitors (Clopidogrel, Prasugrel, Ticagrelor)
-GPIIb/IIIa inhibitors (Tirofiban, Epifibatide)

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2
Q

Indications for antiplatelet agents

A

-Acute coronary syndrome (secondary prevention):
=Dual antiplatelet therapy for 6 months: Aspirin (300 mg loading dose, 75mg OD) + P2Y12 inhibitor (ie. Clopidogrel 300mg/600mg loading dose for emergency PCI so STEMI, 75mg OD) , followed by lifelong single antiplatelet therapy. Thrombotic complications PCI= Triofiban etc

-Stable coronary artery disease: single antiplatelet therapy Aspirin or Clopidogrel (75mg OD)

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3
Q

Important contraindications of antiplatelets

A

-Recent GI/intracranial bleeding
-Bleeding disorders
-Thrombocytopenia

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4
Q

Important side effects/ cautions of antiplatelets

A

GI bleeding (consider co-prescribing with a proton-pump inhibitor [ie. omeprazole])

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5
Q

Mechanism of action: anticoagulants

A

-Oral anticoagulants:
=Vitamin K antagonist (Warfarin) *requires close INR monitoring [half-life ~ up to 2-3 days]
=Direct Factor Xa inhibitor (Apixaban, Rivaroxaban, Edoxaban) [half-life ~ 12 hours]
=Direct thrombin inhibitor (Dabigatran) [half-life ~ 12 hours]

-Parenteral anticoagulants:
=Antithrombin III agonist (Unfractionated heparin) [half-life ~ 60 minutes] *APTT/ACT monitoring
=Antithrombin III-mediated selective inhibition of factor Xa (Fondaparinux) [half-life ~ 15 hours]

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6
Q

Indications: anticoagulants

A

-Acute coronary syndrome: Fondaparinux 2.5mg SC OD (longer half life so one dose) or Unfractionated heparin (frequent bolus/ infusion) if undergoing emergency PCI

-Atrial fibrillation/flutter (prevention of stroke): Warfarin or Direct Factor Xa inhibitor or Direct thrombin inhibitor

-Metallic prosthetic valve (target INR depends on type and location of valve) (only warfarin)

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7
Q

Important contraindications: anticoagulants

A

recent GI/intracranial bleeding, bleeding disorders, thrombocytopenia,
*end-stage renal failure (warfarin or unfractionated heparin should be used as unpredictable bioavailability)

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8
Q

Important side effects/ cautions of anticoagulants

A

Bleeding (Direct Factor Xa inhibitors or Direct thrombin inhibitors should be favoured in patients with labile INR on warfarin), Heparin-induced thrombocytopenia (risk of venous and arterial thrombosis, unfractionated)

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9
Q

Reversal agents for anticoagulants

A

Warfarin (Vitamin K), Unfractionated heparin (protamine), Direct factor Xa inhibitors (adexanet alfa)

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10
Q

Mechanism of action: lipid lowering therapies

A

-HMG-CoA reductase inhibitors
=(Pravastatin < Simvastatin < Atorvastatin < Rosuvastatin)
-Cholesterol-absorption inhibitors (Ezetimibe)- intolerant/ additional
-PCSK9 inhibitors (Evolocumab, Alirocumab)- inactivated LDL receptors, severe FH
-Fibrates (infrequently used due to limited evidence)

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11
Q

Indications: lipid lowering therapies

A

-Primary prevention of CVD
=in particular, patients with important risk factors (ie. type 2 diabetes, chronic kidney disease, familial hypercholesterolaemia)
-Secondary prevention of CVD

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12
Q

Important contraindications: lipid lowering therapies

A

acute liver disease, pregnancy and breastfeeding (delay or advice contraception in women of childbearing age)

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13
Q

Important side effects/ cautions: lipid lowering therapies

A

GI disturbance (ie diarrhoea), muscle aches, rhabdomyolysis (increased risk with concurrent fibrates and cytochrome P450 inhibitors ie. macrolide antibiotics, antifungals)

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14
Q

Mechanism of action: renin-angiotensin-aldosterone system antagonists

A

-Angiotensin-converting enzyme inhibitor, ACEi (ie. Ramipril, Enalapril)
-Angiotensin receptor blocker, ARB (ie. Losartan, Candesartan)
-Mineralocorticoid receptor antagonist, MRA (ie. Spironolactone, Eplerenone)

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15
Q

Indications: renin-angiotensin-aldosterone system antagonists

A

-Chronic Heart failure (ACEi/ARBs + MRA)
-Hypertension (ACEi/ARBs)
-Post-MI secondary prevention (ACEi/ARBs)

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16
Q

Important contraindications: renin-angiotensin-aldosterone system antagonists

A

ACEi/ARBs: severe aortic stenosis, bilateral renal artery stenosis, pregnancy

17
Q

Important side effects/cautions: renin-angiotensin-aldosterone system antagonists

A

renal impairment, hyperkalaemia
ACEi: angioedema, first dose hypotension, dry cough

18
Q

Newer heart failure therapies

A

-Angiotensin receptor and Neprilysin inhibitor, ARNI (secubitril/valsartan)
-Inhibitors of sodium–glucose cotransporter 2, SGLT2 (ie. dapaglifozin)

19
Q

Mechanism of action: Diuretics

A

-Loop diuretics (ie. Furosemide, Bumetanide) ascending loop
-Thiazide diuretics (ie. Bendroflumethiazide, Indapamide, Metolazone) distal convoluted
-Potassium sparing diuretics (MRAs, Amiloride, Triamterene)

20
Q

Indications: diuretics

A

-Decompensated heart failure
-Hypertension

21
Q

Important side effects/ caution: diuretics

A

Hypovolaemia, Hyponatraemia, Hypokalaemia (loop diuretic), Hyperkalaemia (potassium sparing diuretics), renal impairment

22
Q

Monitoring of diuretics

A

-Careful titration to fluid status
-Start at lower dose for diuretic-naïve patients
-Monitor potassium, sodium and creatinine levels

23
Q

Mechanism of action: beta-blockers

A

-Inhibition of noradrenaline at β‎-adrenceptors (β1‎, β‎2)
=negatively inotropic and chronotropic

24
Q

Indications: beta-blocker

A

-Angina
-Chronic heart failure
-Post-MI secondary prevention
-Atrial fibrillation
-Suppression of ventricular and supraventricular arrhythmia

25
Q

Important contraindications: beta-blocker

A

2nd/3rd degree heart block, severe peripheral vascular disease, asthma/bronchospasm, patients on verapamil

26
Q

Important side effects/ cautions: beta-blockers

A

bradycardia, hypotension, fatigue, bronchospasm, sleep disturbance

27
Q

Mechanism of action: calcium channel blockers

A

-Inhibit inward movement of Ca2+
=Dihydropyridine, DHP (more affinity for vascular smooth muscles) ie. Amlodipine, Felodipine
==peripheral vasodilation, reduction in BP and reduce afterload

-Non-Dihydropyridine, non-DHP (more affinity on myocardium and cardiac conductive system)- ie. Verapamil, Diltiazem
=negatively inotropic and chronotropic (angina, AF)

28
Q

Indications: calcium channel blockers

A

-Hypertension (DHP)
-Angina (both DHP and nonDHP)
-Atrial fibrillation (non-DHP)

29
Q

Important contraindications: calcium channel blockers

A

Hypotension, severe aortic stenosis, AV block (non-DHP), heart failure, patients on beta blockers (non-DHP)

30
Q

Important side effects/ cautions: calcium channel blockers

A

bradycardia, hypotension, ankle oedema, constipation

31
Q

Mechanism of action: nitrates

A

-Vasodilation and venodilation-> reduce preload and afterload
-improve coronary blood flow and myocardial oxygen demand

32
Q

Preparations of nitrates

A

-Sublingual GTN- tablet/spray: repeat every 5-10 minutes, urgent medical advice if CP does not resolve after 2 doses
-Oral isosorbide mononitrate- short acting: 20-40mg BD or long acting: 60-120mg OD
=asymmetric dosing to allow nitrate free period
-IV GTN- infusion 10-200 micrograms/min titrated to chest pain/BP, acute decompensated

33
Q

Indications: nitrates

A

-Angina
-Acute heart failure

34
Q

Important contraindications: nitrates

A

Aortic stenosis, HOCM, patients on sildenafil

35
Q

Important side effects/ cautions: nitrates

A

-Hypotension, headache

36
Q

Other antianginals

A

-Nicorandil (potassium-channel activator)
-Ivabradine (If channel inhibition in sino-atrial node)

37
Q

Nicorandil overview

A

-Potassium-channel activator)
-Activation of potassium channels lead to vasodilation and venodilation, reduced afterload and preload, similar effect as nitrates
-Important side-effects: headache, hypotension, ulceration in skin/mucosal membrane

38
Q

Ivabradine overview

A

-If channel inhibition in sino-atrial node
reduction in heart rate only in patients in sinus rhythm
often used in patients who are intolerant to Beta blockers
-Also used to treat chronic heart failure
-Important side-effects: bradycardia, visual symptoms