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What type of drugs inhibit platelet function?
What type of drugs inhibit platelet function?
What is a common side-effect of warfarin?
What is a common side-effect of warfarin?
Can warfarin be used in breast-feeding mothers?
Can warfarin be used in breast-feeding mothers?
What is a rare side-effect of warfarin?
What is a rare side-effect of warfarin?
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What is the name of the oral anticoagulant mentioned in the text?
What is the name of the oral anticoagulant mentioned in the text?
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Why does warfarin increase the risk of hemorrhage?
Why does warfarin increase the risk of hemorrhage?
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What is a teratogenic effect of warfarin?
What is a teratogenic effect of warfarin?
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When does warfarin cause skin necrosis?
When does warfarin cause skin necrosis?
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What is the effect of warfarin on protein C biosynthesis?
What is the effect of warfarin on protein C biosynthesis?
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What is a potential complication of thrombosis in venules?
What is a potential complication of thrombosis in venules?
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What is a benefit of DOACs compared to Vitamin K antagonists?
What is a benefit of DOACs compared to Vitamin K antagonists?
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What is a symptom associated with thrombosis in venules?
What is a symptom associated with thrombosis in venules?
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What is a characteristic of DOACs?
What is a characteristic of DOACs?
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What is a common location where thrombosis may occur?
What is a common location where thrombosis may occur?
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What is a complication of thrombosis in venules?
What is a complication of thrombosis in venules?
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What type of anticoagulants are DOACs?
What type of anticoagulants are DOACs?
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What is a benefit of DOACs over Vitamin K antagonists?
What is a benefit of DOACs over Vitamin K antagonists?
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What is a characteristic of thrombosis in venules?
What is a characteristic of thrombosis in venules?
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What is a symptom associated with thrombosis?
What is a symptom associated with thrombosis?
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What is warfarin primarily used to prevent?
What is warfarin primarily used to prevent?
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What is monitored in patients taking warfarin?
What is monitored in patients taking warfarin?
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What is the purpose of measuring the INR in patients taking warfarin?
What is the purpose of measuring the INR in patients taking warfarin?
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What is the name of the ratio used to monitor warfarin's effectiveness?
What is the name of the ratio used to monitor warfarin's effectiveness?
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What is a common indication for warfarin therapy?
What is a common indication for warfarin therapy?
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Why is warfarin considered a narrow therapeutic index drug?
Why is warfarin considered a narrow therapeutic index drug?
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What is the purpose of taking warfarin in patients with mechanical heart valves?
What is the purpose of taking warfarin in patients with mechanical heart valves?
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What is the relationship between the INR and the prothrombin time?
What is the relationship between the INR and the prothrombin time?
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What is the indication for warfarin therapy in patients with venous thromboembolism?
What is the indication for warfarin therapy in patients with venous thromboembolism?
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What is the primary goal of warfarin therapy?
What is the primary goal of warfarin therapy?
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Study Notes
Lipid-Lowering Drugs
- HMG-CoA reductase inhibitors, PCSK9 MAB, niacin, ezetimibe, and resins are used to treat hyperlipidemias, such as secondary sarcoidosis.
- These drugs work by reducing cholesterol levels, leading to increased bile acid synthesis.
Pulmonary Arterial Hypertension (PAH)
- Exertional dyspnea is the most common symptom of PAH.
- Chest pain and syncope may also occur.
- Characteristic physical examination findings include loud P2 (Pulmonic closure sound) and left parasternal heave (due to right ventricular hypertrophy).
Management of PAH
- Treatment should first involve addressing any underlying conditions, such as with anticoagulants or oxygen.
- If there is a positive response to acute vasodilator testing, oral calcium channel blockers can be used.
Pathophysiology of PAH
- Three pathways are involved in the development of PAH:
- Nitric oxide pathway
- Prostacyclin pathway
- Endothelin pathway
Anticoagulants
- Warfarin is an oral anticoagulant with a long half-life, requiring several days to achieve a stable INR.
- Factors that may potentiate warfarin:
- Liver disease
- P450 enzyme inhibitors (e.g., amiodarone, ciprofloxacin)
- Cranberry juice
- Drugs that displace warfarin from plasma albumin (e.g., NSAIDs)
- Drugs that inhibit platelet function (e.g., NSAIDs)
- Side effects of warfarin:
- Hemorrhage
- Teratogenic effects (although safe for breast-feeding mothers)
- Skin necrosis (when warfarin is first started, biosynthesis of protein C is reduced)
Acute Vasodilator Testing
- Aims to determine which patients show a significant fall in pulmonary arterial pressure following vasodilator administration
- Vasodilators used: IV Epoprostenol, inhaled nitric oxide, prostacyclin analogues (iloprost, treprostinil), and phosphodiesterase-5 (PDE-5) inhibitors (sildenafil)
Blood Coagulation
Platelet Aggregation and Blood Coagulation
- Involved in antiplatelet drugs and anticoagulants
Antiplatelet Drugs
- No specific information provided
Anticoagulants
Injectable Anticoagulants
- Standard heparin: administered intravenously, short duration of action, side effects include bleeding, heparin-induced thrombocytopenia (HIT), and osteoporosis
- Low molecular weight heparin (LMWH): administered subcutaneously, long duration of action, side effects include bleeding, lower risk of HIT and osteoporosis
Monitoring
- Standard heparin: monitored using activated partial thromboplastin time (APTT)
- LMWH: monitored using anti-Factor Xa (although routine monitoring is not required)
- Heparin overdose may be reversed by protamine sulphate, although this only partially reverses the effect of LMWH
Indications
- Venous thromboembolism
- Atrial fibrillation
- Mechanical heart valves
Oral Anticoagulants
Warfarin
- Monitored using the INR (international normalised ratio)
- Has a long half-life, achieving a stable INR may take several days
- Factors that may potentiate warfarin:
- Liver disease
- P450 enzyme inhibitors (e.g. amiodarone, ciprofloxacin)
- Cranberry juice
- Drugs that displace warfarin from plasma albumin
- Thrombosis may occur in venules, leading to skin necrosis and purple toes
Direct Oral Anticoagulants (DOACs)
- Have a fixed dosing regimen and do not require frequent monitoring
- Offer greater convenience to patients compared to Vitamin K antagonists (e.g. warfarin)
Disorders of Lipid Metabolism
- Disorders of lipid metabolism can occur as primary conditions (familial or polygenic) or secondary to an underlying disease state or drug treatment.
- Risks of dyslipidemias include increased risk of atherosclerosis, ischaemic heart disease, cerebrovascular disease, and peripheral vascular diseases, directly related to increasing levels of serum cholesterol.
Management of Dyslipidemias
- Increase intake of unsaturated fats (e.g., olive oil, salmon, cashews, almonds) to help manage dyslipidemias.
- Increase physical activity to reduce risks of dyslipidemias.
Lipid-Lowering Drugs
- Statins: inhibit HMG CoA reductase, reducing cholesterol synthesis; examples include Atorvastatin, Simvastatin, and Rosuvastatin; adverse effects include muscle pain (myositis) and liver damage.
- Ezetimibe: decreases cholesterol absorption in the small intestine; adverse effects include headache.
- Nicotinic acid (Niacin, Vit B3): decreases hepatic VLDL secretion; adverse effects include myositis and flushing.
- Fibrates: agonist of PPAR-alpha, increasing lipoprotein lipase expression; examples include Gemfibrozil and Fenofibrate; adverse effects include myositis, pruritus, and cholestasis.
- Cholestyramine: binds bile acid, decreasing reabsorption in the small intestine; adverse effects include GI side-effects.
Pulmonary Arterial Hypertension (PAH)
- Defined as a sustained elevation in mean pulmonary arterial pressure (>25 mmHg at rest or >30 mmHg after exercise).
- Acute vasodilator testing: decides which patients show a significant fall in pulmonary arterial pressure following vasodilator administration (e.g., IV Epoprostenol or inhaled nitric oxide).
- Indications for PAH treatment include venous thromboembolism, atrial fibrillation, and mechanical heart valves.
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Description
This quiz covers the sites of action of various lipid-lowering drugs, including HMG-CoA reductase inhibitors, PCSK9 MAB, niacin, ezetimibe, and resins, used to treat hyperlipidemias. Understand the mechanisms of these drugs in reducing cholesterol levels.
