40. Antiarrhythmics Flashcards
Dronedarone carries boxed warning against use in which of the following types of patients: (Select ALL that apply.)
A. Class IV heart failure
B. Permanent atrial fibrillation
C. Recurrent atrial fibrillation
D. Paroxysmal atrial fibrillation
E. Peripheral arterial disease
A, B. Dronedarone has been shown to be associated with worse outcomes in patients with moderate-severe heart failure, and when used in patients with permanent atrial fibrillation.
dronedarone (Multaq): PO. with meals. Boxed warning: HF (NYHA Class IV or any with recent hospitalization) and in patients with permanent AFib. CI: 2nd/3rd degree heart block, symptomatic heart failure, HR<50, concomitant use of strong 3A4 inhbitors and drugs that prolong QT, QT≥500ms, PR interval>280ms, lung or liver toxicity, severe hepatic impairment, pregnancy (X), nursing mothers. Warning: hepatic failure, lung disease, marked increase in SCr, prerenal azotemia, heart failure and acute renal failure have been reported in setting of HF or hypovolemia, hypokalemia, hypomagnesemia, concomitant administration of K-depleting diuretics. SE: QT prolongation, increase SCr, nausea, vomiting, abdominal pain, diarrhea, bradycardia, dermatitis, asthenia
Jack is a 77 year-old male with heart failure who is receiving a new prescription for amiodarone. The pharmacist will counsel the patient on risks to these organs with amiodarone therapy:
A. Liver, kidney, and eyes
B. Liver, colon, and kidney
C. Kidney, gall bladder, and CNS
D. Thyroid, pancreas, and liver
E. Thyroid, liver, and lungs
E. The patient should receive baseline laboratory function tests of these organs.
amiodarone (Cordarone, Pacerone, Nexterone): PO, IV. infusions longer than 2 hours need non-PVC. drug of choice in HF patients. long half life.(40-60 days) Boxed warning: only for life-threatening arrhythmias due to toxicity (patients should be hospitalized when therapy is initiated), pulmonary toxicity, liver toxicity, exacerbation of arrhythmias. CI: severe sinus-node dysfunction, 2nd/3rd degree heart block, bradycardia causing syncope, cardiogenic shock, hypersensitivity to iodine. SE: hypotension, bradycardia, corneal microdeposits, dizziness, ataxia, GI upset, constipation, peripheral neuropathy, tremor, hypo/hyper-thyroidism (more hypo), optic neuritis, pulmonary fibrosis, photosensitivity, increase LFts, slate blue (blue-grayish) skin discoloration, pregnancy (D). when starting amiodarone, decrease digoxin dose by 50% and warfarin by 30-50%.
A patient is beginning digoxin 0.125 mg daily. The patient has mild renal insufficiency. After a few weeks, the patient develops an infection with nausea and vomiting. She is weak, dehydrated and bradycardic. The patient is admitted to the hospital. Which of the following statements are correct? (Select ALL that apply.)
A. Hyperkalemia may increase the risk of digoxin toxicity more than hypokalemia.
B. Digoxin is mainly eliminated by the kidney and decreased renal function can lead to supratherapeutic levels.
C. An elevated digoxin level can worsen nausea and vomiting.
D. Mental confusion and bradycardia can be caused by an elevated digoxin level.
E. Digoxin toxicity should be treated with beta-agonists.
B, C, D. Digoxin is renally eliminated; elevated levels can cause nausea/vomiting as well as mental confusion and bradycardia.
digoxin (Digox, Lanoxin): PO, IV. used for rate control but not first line. only reduces resting heart rate (not during exercise). inhibits Na/K ATPase pump which results in positive inotropic effect (increase CO) and provides negative chronotropic effect (decrease HR)therapeutic range for AFib = 0.8-2.0ng/mL. CI: ventricular fibrillation. Warning: 2nd/3rd degree heart block, Wolff-Parkinson-White syndrome with AFib. SE: dizziness, mental disturbances, headache, diarrhea, nausea, vomiting. Signs of toxicity: nausea/vomiting, loss of appetite, bradycardia, blurred/double vision, altered color perception, abdominal pain, confusion, delirium, arrhythmia. Antidote: DigiFab. Therapeutic range for HF: 0.5-0.9ng/mL (higher range for AFib). Decrease dose when CrCl<30. Hypokalemia, hypomagnesemia, and hypercalcemia increase risk of digoxin toxicity.
What class of antiarrhythmic is amiodarone in according to the Vaughn Williams classification system?
A. Ia
B. Ib
C. Ic
D. III
E. IV
D.
Ia: procainamide, disopyramide, quinidine
Ib: lidocaine, mexiletine
Ic: flecainide, propafenone
“police department questions liquored man for peeing”
II: beta blockers
III: amiodarone, dronedarone, sotalol, ibutilide, dofetilide “after drinking scotch in dark”
IV: diltiazem, verapamil
Which of the following drugs is used to control ventricular rate in a patient presenting in atrial fibrillation with a rapid ventricular response?
A. Quinidine
B. Digoxin
C. Sotalol
D. Procainamide
E. Mexiletine
B. Digoxin acts to slow AV nodal conduction through a vagal effect. Although not effective for preventing exercise induced increases in heart rate, it does decrease resting heart rate. Although sotalol has beta-blocking effects, it is used to maintain sinus rhythm (rhythm control agent), not as ventricular rate controlling agent.
digoxin (Digox, Lanoxin): PO, IV. used for rate control but not first line. only reduces resting heart rate (not during exercise). inhibits Na/K ATPase pump which results in positive inotropic effect (increase CO) and provides negative chronotropic effect (decrease HR)therapeutic range for AFib = 0.8-2.0ng/mL. CI: ventricular fibrillation. Warning: 2nd/3rd degree heart block, Wolff-Parkinson-White syndrome with AFib. SE: dizziness, mental disturbances, headache, diarrhea, nausea, vomiting. Signs of toxicity: nausea/vomiting, loss of appetite, bradycardia, blurred/double vision, altered color perception, abdominal pain, confusion, delirium, arrhythmia. Antidote: DigiFab. Therapeutic range for HF: 0.5-0.9ng/mL (higher range for AFib). Decrease dose when CrCl<30. Hypokalemia, hypomagnesemia, and hypercalcemia increase risk of digoxin toxicity.
Conrad is a 60 year-old obese male whose total cholesterol measured 312 mg/dL several years ago. He believed that high cholesterol was his only medical condition because that is all the doctor had mentioned. He refused medicine because he felt fine. The only thing he takes is a daily aspirin and one or two fish oil capsules. Recently, Conrad cut off a finger by accident while working in his wood shop. When he arrived at the hospital, he was in atrial fibrillation and was started on digoxin. Which of the following statements regarding digoxin is correct?
A. Digoxin decreases vagal tone which reduces the resting heart rate.
B. Digoxin dose should be decreased by 25% when switching from oral to IV
C. Digoxin blocks the K+/H+ ATPase pump
D. Digoxin is pregnancy category X.
E. Digoxin has a short half-live of 2 hours.
B. Digoxin enhances vagal tone, blocks the Na+/H+ ATPase pump, has a ~24-48 hour half-life and is pregnancy category C.
digoxin (Digox, Lanoxin): PO, IV. used for rate control but not first line. only reduces resting heart rate (not during exercise). inhibits Na/K ATPase pump which results in positive inotropic effect (increase CO) and provides negative chronotropic effect (decrease HR)therapeutic range for AFib = 0.8-2.0ng/mL. CI: ventricular fibrillation. Warning: 2nd/3rd degree heart block, Wolff-Parkinson-White syndrome with AFib. SE: dizziness, mental disturbances, headache, diarrhea, nausea, vomiting. Signs of toxicity: nausea/vomiting, loss of appetite, bradycardia, blurred/double vision, altered color perception, abdominal pain, confusion, delirium, arrhythmia. Antidote: DigiFab. Therapeutic range for HF: 0.5-0.9ng/mL (higher range for AFib). Decrease dose when CrCl<30. Hypokalemia, hypomagnesemia, and hypercalcemia increase risk of digoxin toxicity.
What class of antiarrhythmic is verapamil in according to the Vaughn Williams classification system?
A. Ia
B. Ib
C. Ic
D. III
E. IV
E.
Ia: procainamide, disopyramide, quinidine
Ib: lidocaine, mexiletine
Ic: flecainide, propafenone
“police department questions liquored man for peeing”
II: beta blockers
III: amiodarone, dronedarone, sotalol, ibutilide, dofetilide “after drinking scotch in dark”
IV: diltiazem, verapamil
A patient presents with a supraventricular tachycardia. The rhythm is terminated with adenosine. Which of the following correctly describes adenosine’s pharmacology?
A. Beta-1 receptor agonist
B. Calcium channel antagonist
C. Potassium channel agonist
D. Sodium channel antagonist
E. Adenosine receptor agonist
E. Adenosine works by activating A1 receptors in the AV node, causing transient AV block which can terminate re-entrant arrhythmias involving the AV node.
adenosine (Adenocard): IV. activates adenosine-1 receptors to slow conduction through AV node. used in paroxysmal supraventricular tachycardia. 2nd/3rd degree heart block, sick sinus syndrome, symptomatic bradycardia, bronchospastic lung disease. SE: transient new arrhythmia, facial flushing, chest pain/pressure, neck discomfort, dizziness, headache, GI distress, transient decrease in blood pressure, dyspnea
Jack has been using amiodarone for nine months. Long-term therapy with amiodarone can cause the following thyroid problems: (Select ALL that apply.)
A. Hypothyroidism, as demonstrated by a high TSH and low FT4
B. Hypothyroidism, as demonstrated by a low TSH and high FT4
C. Hyperthyroidism, as demonstrated by a low TSH and high FT4
D. Hyperthyroidism, as demonstrated by a high TSH and low FT4
E. Amiodarone does not affect the thyroid
A, C. The incidence of amiodarone-induced thyroid dysfunction is about 4% of patients. The effects range from abnormal thyroid function test findings to overt thyroid dysfunction, which can manifest as either hyperthyroidism or hypothyroidism. All patients using amiodarone should have the thyroid function monitored (by the primary parameters FT4 and TSH), along with symptoms.
amiodarone (Cordarone, Pacerone, Nexterone): PO, IV. infusions longer than 2 hours need non-PVC. drug of choice in HF patients. long half life.(40-60 days) Boxed warning: only for life-threatening arrhythmias due to toxicity (patients should be hospitalized when therapy is initiated), pulmonary toxicity, liver toxicity, exacerbation of arrhythmias. CI: severe sinus-node dysfunction, 2nd/3rd degree heart block, bradycardia causing syncope, cardiogenic shock, hypersensitivity to iodine. SE: hypotension, bradycardia, corneal microdeposits, dizziness, ataxia, GI upset, constipation, peripheral neuropathy, tremor, hypo/hyper-thyroidism (more hypo), optic neuritis, pulmonary fibrosis, photosensitivity, increase LFts, slate blue (blue-grayish) skin discoloration, pregnancy (D). when starting amiodarone, decrease digoxin dose by 50% and warfarin by 30-50%.
Sotalol is classified in which Vaughan Williams class?
A. Ia
B. Ib
C. Ic
D. II
E. III
E. Although sotalol has beta-blocking effects, it is a potent potassium channel blocker and is classified as a class III antiarrhythmic.
Ia: procainamide, disopyramide, quinidine
Ib: lidocaine, mexiletine
Ic: flecainide, propafenone
“police department questions liquored man for peeing”
II: beta blockers
III: amiodarone, dronedarone, sotalol, ibutilide, dofetilide “after drinking scotch in dark”
IV: diltiazem, verapamil
Which Vaughan Williams classification represents agents that bind to Na+ channels for a prolonged period of time (long-acting)?
A. Ia
B. Ib
C. Ic
D. II
E. III
C.
Primary Ion Channels
Class Ia – intermediate DoA: Na blocker
Class Ib – fast DoA: Na blocker
Class Ic – long DoA: Na blocker
Class II: beta blockers (indirect calcium channel blockers)
Class III: potassium channel blockers
Class IV: calcium channel blockers (direct)
“Some block potassium channels” = sodium blocker, beta blocker, potassium blocker, calcium blocker
Class I and III are rhythm control: convert/maintain normal sinus rhythm
Class II and IV are rate control
Multaq has a warning against use with any of the following medications: voriconazole, ritonavir, telithromycin, ketoconazole, itraconazole, clarithromycin, cyclosporine and grapefruit. Which statement correctly describes the risk if Multaq is administered with any of these medications?
A. This statement is incorrect; Multaq is preferred because it has few significant drug interactions.
B. These are strong CYP 3A4 inducers; Multaq is a 3A4 substrate and concurrent use would increase the concentration and could cause an arrhythmia and other adverse reactions.
C. These are strong CYP 3A4 inhibitors; Multaq is a 3A4 substrate and concurrent use would increase the concentration and could cause an arrhythmia and other adverse reactions.
D. If administered together, the patient is at high risk for hypersensitivity.
E. If administered together, the concentration of Multaq would decrease and the arrhythmia would not be treated.
C. Both dronedarone (Multaq) and amiodarone are CYP 3A4 substrates; do not use with 3A4 inhibitors.
dronedarone (Multaq): PO. with meals. Boxed warning: HF (NYHA Class IV or any with recent hospitalization) and in patients with permanent AFib. CI: 2nd/3rd degree heart block, symptomatic heart failure, HR<50, concomitant use of strong 3A4 inhbitors and drugs that prolong QT, QT≥500ms, PR interval>280ms, lung or liver toxicity, severe hepatic impairment, pregnancy (X), nursing mothers. Warning: hepatic failure, lung disease, marked increase in SCr, prerenal azotemia, heart failure and acute renal failure have been reported in setting of HF or hypovolemia, hypokalemia, hypomagnesemia, concomitant administration of K-depleting diuretics. SE: QT prolongation, increase SCr, nausea, vomiting, abdominal pain, diarrhea, bradycardia, dermatitis, asthenia
What phase of the cardiac action potential does propranolol mainly work?
A. Phase 0
B. Phase 1
C. Phase 2
D. Phase 3
E. Phase 4
C. Propranolol works mainly on phase 2 of the cardiac action potential.
Phase 0 is depolarization (Na channels open, Na enters)
Phase 1 is peak (Na channels close)
Phase 2 is plateau (Ca channel opens, K channel opens, Ca enters, K exits)
Phase 3 is repolarization (Ca channel closes, K exits)
Phase 4 is automaticity (slow increase in potential)
What class of antiarrhythmic is mexiletine in according to the Vaughn Williams classification system?
A. Ia
B. Ib
C. Ic
D. III
E. IV
B.
Ia: procainamide, disopyramide, quinidine
Ib: lidocaine, mexiletine
Ic: flecainide, propafenone
“police department questions liquored man for peeing”
II: beta blockers
III: amiodarone, dronedarone, sotalol, ibutilide, dofetilide “after drinking scotch in dark”
A patient was using furosemide 40 mg twice daily (at 8 am and 12 noon) for heart failure. The doctor forgot to call in a prescription for potassium when he called the pharmacy to order the furosemide. The patient’s other medications include carvedilol, digoxin and aspirin. The patient ran out of the potassium. The patient is at increased risk for:
A. Digoxin toxicity
B. Carvedilol toxicity
C. Aspirin toxicity
D. Furosemide toxicity
E. None of the above
A. Hypokalemia may increase the risk of digoxin toxicity. The potassium must be kept within the normal physiologic range when using digoxin.
digoxin (Digox, Lanoxin): PO, IV. used for rate control but not first line. only reduces resting heart rate (not during exercise). inhibits Na/K ATPase pump which results in positive inotropic effect (increase CO) and provides negative chronotropic effect (decrease HR)therapeutic range for AFib = 0.8-2.0ng/mL. CI: ventricular fibrillation. Warning: 2nd/3rd degree heart block, Wolff-Parkinson-White syndrome with AFib. SE: dizziness, mental disturbances, headache, diarrhea, nausea, vomiting. Signs of toxicity: nausea/vomiting, loss of appetite, bradycardia, blurred/double vision, altered color perception, abdominal pain, confusion, delirium, arrhythmia. Antidote: DigiFab. Therapeutic range for HF: 0.5-0.9ng/mL (higher range for AFib). Decrease dose when CrCl<30. Hypokalemia, hypomagnesemia, and hypercalcemia increase risk of digoxin toxicity.
