Antiarrhythmic - Diuretics - Hyperlipidemia Flashcards
Polymorphic ventricular tachycardia, often displaying waxing and waning QRS amplitude in ECG
Torsades de Pointes
Two arrhythmogenic mechanisms
- Abnormal automaticity
2. Abnormal conduction
What are the different class of antiarrhythmic drugs based on Singh Vaughan Williams Classifications
Class 1: Sodium channel blockers
Class 2: Beta-adrenoceptor blockers
Class 3: Potassium channel blockers
Class 4: Calcium channel blockers
What portion of the cardiac action potential does the Class 1 antiarrhythmic drugs act on?
Phase 0
Class 1A antiarrhythmic drug that has a lupus like syndrome side effects
Procainamide - used for atrial and ventricular arrhythmias, especially after MI
A class 1A antiarrhythmic drug that has a marked antimuscarinic effects
Disopyramide
Antiarrhythmic drug that is also used in malaria with a side effect of having cinchonism and autoimmune reactions (ITP)
Quinidine - reduces clearance of digoxin
Treatment for class 1A overdose
Sodium lactate - reverse drug induced arrhythmias
Antiarrhythmic drugs that reduces AP duration, selectively affects ischemic or depolarized Purkinje and ventricular tissues. Have little effect on the ECG
Group 1B antiarrhythmic drugs
Drug of choice for ventricular arrhythmias post-myocardial infarction. It is also the least cardiotoxic among conventional anti-arrhythmic drugs
Lidocaine
Antiarrhythmic drug that has a powerful depressants of sodium current. Can markedly slow conduction velocity in atrial and ventricular cells
Group 1C antiarrhythmic drugs
Anti arrhythmic drug used for refractory arrhythmias, contraindicated for post MI arrhythmia
Flecainide
Class IA drugs used for WPW syndrome
Procainamide and Amiodarone
Class 2 antiarrhythmic drugs act on what phase of action potential?
Phase 4 - AV node is particularly sensitive to blockers
Class 2 antiarrhythmic drug used for post - MI prophylaxis against sudden death and thyrotoxicosis
Propranolol - slowed pacemaker activity
Beta-blocker lacking local anesthetic effect
Timolol
Beta-blocker with low lipid solubility
Atenolol
Antiarrhythmic drug that acts on phase 3, hallmark is prolongation of the AP duration, ECG: increAse in QT interval
Class 3 antiarryhythmic drugs - blockade of potassium that are responsible for the repolarization of the AP
Class 3 antiarrhythmic drug used for treatment and prophylaxis of atrial fibrillation
Dofetilide - side effects: Torsades de pointes
A beta-blocker that has class 3 properties, used for ventricular arrhythmia and atrial fibrillation
Sotalol
Class 3 antiarrhythmic drug used for refractory arrhythmias, most efficacious of all antiarrhythmic drugs.
Amiodarone - it has group 1, group 2 and 4 effects
Toxicity results to pulmonary fibrosis, paresthesias, tremors, thyroid dysfunctions, corneal deposits, and skin deposits
Amiodarone toxicity
Group of drugs effective in arrhythmias that must traverse calcium dependent cardiac tissues (AV node). ECG: PR interval is consistently increased
Class 4 antiarrhythmic drugs
Why are dihydropyridine calcium channel blockers not useful as antiarrhythmics?
Dihydropyridine CCBs evoke compensatory sympathetic discharge which facilitates arrhythmias rather than terminating them
Class 4 antiarrhythmic drug used for Reynaud’s phenomenon
Diltiazem
Site of active sodium and chloride pump out of the lumen of the nephron via Na/Cl carrier
Distal convoluted tubule
It is a miscellaneous antiarrhythmic drug of choice for paroxysmal supraventricular tachycardia
Adenosine
Major site for sodium chloride and sodium bicarbonate reabsoption (60-70%)
Proximal convoluted tubule
Carbonic anhydrase inhibitor drug used for glaucoma,
Acetazolamide - SE: hyperchloremic metabolic acidosis (NAGMA)
Site for sodium chloride reabsoption via Na/K/2Cl transporter
Thick ascending loop of Henle
Site of calcium and magnesium reabsorption
Thick ascending loop of Henle
Important in maintaining glomerular filtration
Prostaglandins
Drugs that decreases the efficacy of loop diuretics
NSAIDs
Site for last tubular sodium reabsoption, reabsorbing (2-5%) of sodiu via channels
Cortical collecting ducts
Loop diuretic that has synergistic effect with aminoglycosides. Half life of 6 hours used for heart failure and pulmonary edema
Furosemide - SIMD: Ethacrynic acid
Primary site of acidification of urine, last site of potassium excretion
Cortical collecting duct
Site of reabsorption of water occurs under the control of antidiuretic hormones (ADH)
Medullary collecting duct
Calcium is also reabsorbed at this distal convoluted tubule under the control of what hormone?
PTH
Diuretic used for hyperaldosteronism, SE: gynecomastia, impotence
Spironolactone - SIMD: Eplerenone - reduces progression of DM nephropathy
Remains in the lumen and holds water by virtue of its osmotic effect. Used for rhabdomyolysis and increased intracranial pressure
Mannitol
Drugs effective in lowering LDL cholesterol except:
Statins, fibrates, resins, ezetimibe, niacin
Fibrates - has no or little effect on LDL concentrations
Potassium - sparing diuretic (Na blocker) used for hypokalemia. SE: hyperkalemia, acute renal failure and kidney stones
Amiloride
An ADH antagonist used for SIADH and hyponatremia
Conivaptan
Drug used for hypercholesterolemia (high LDL), pruritus in cholestasis. SE: steatorrhea, constipation and malabsorption
Cholestyramine - bile acid binding resin
Conditioned highly associated with acute pancreatitis
Hyperchylomicronemia
Drugs most effective in lowering triglycerides and VLDL, increasing HDL
Niacin and fibrates
It raises triglyceride and VLDL levels and should be avoided in patients with hyoertriglyceridemia
Alcohol
Has anti-atherosclerotic effects and prevent bone loss. However, had increased risk of myopathy and rhabdomyolysis when used with fibrates
Simvastatin - reversible competitive inhibitor of HMG-CoA reductase
Drug converted to glucuronide form in the liver, it inhibits NPC1L1 transporter and prevents absorptionof dietary cholesterol and cholesterol that is excreted in bile
Ezetimibe - with synergistic effect with Statins in lowering LDL
Most effective agent for increasing HDL levels, reduces LDL cholesterol, triglycerides and VLDL. Both vitamin and antihyperlipidemic drug
Niacin - aspirin pre-treatment reduces flushing, avoid in patients with peptic ulcer disease
90% of bile acids are reabsorbed and returned to the liver for reuse via?
Enterohepatic recirculation
Synergistic combination for Familial combined hypercholesterolemia?
Niacin + Resin or Statin + Fibrate
Disadvantage of Statin and Fibrate combination
Increased risk of myopathy and rhabdomyolysisw
A sterol absorption blocker used for hypercholesterolemia by acting as cholesterol analog
Sitosterol
Used as an antiarrhythmic drug by depressing ectopic pacemakers, including those caused by digitalis toxicity
Potassium ion
Drug that activates PPAR-a, increases expression of lipoprotein lipase and apolipoproteins apoA-I and apoA-II. Drug of choice for hyperetriglyceridemia but increased risk for cholesterol gallstones
Gemfibrozil - fibric acid derivative
Combination of hyperlipidemic drugs that may increase risk of cholithiasis
Fibrate + Resin
Synergistic combination for familial hypercholesterolemia?
Niacin + Statins or Statin + Ezetimibe
ADH agonist - act at V1 and V2 ADH receptors used in central diabetes insipidus
Desmopressin
What would be the blood pH if using both loop diuretics and thiazides?
Alkalemia
Thiazide diuretic that has synergistic effect with loop diuretics
Hydrochlorothiazide
Toxicity results to ototoxicity, hypokalemia, dehydration, allergy to sulfa drugs, nephritis and gout
Loop diuretic toxicity
Site of uric acid transport
Proximal convoluted tubules
