Chapter 49: Antidysrhythmic Drugs Flashcards
Which dysrhythmias are more dangerous: atrial or ventricular? What dysrhythmia results in the lowest cardiac output and what is the treatment of this life-threatening rhythm?
Ventricular dysrhythmias are more dangerous than atrial dysrhythmias. Ventricular fibrillation is the most dangerous dysrhythmia with the least amount of cardiac output. Treatment requires defibrillation and/or CPR.
What is the MAJOR adverse effect of antidysrhythmic drugs?
NEW DYSRHYTHMIAS
What is the basic mechanism of action for Class I, II, II, and IV antidysrhythmics?
Class I: Sodium channel blockers
Class II: Beta blockers
Class III: Potassium channel blockers (delay repolarization)
Class IV: Calcium Channel blockers
What is Quinidine? What class of drug is this? What are its adverse effects? What changes specific to an EKG reading?
Quinidine: Class I A antidysrhythmic drug. It is an anticholinergic one and can cause excessive ventricular stimulation. QRS complex is widened by slowing depolarization of the ventricles and prolongs the QT interval by delaying ventricular repolarization . Other adverse effects: diarrhea, cinchonism (tinnitus, H/A, N/V, disturbed vision, and vertigo), cardiovascular toxicity: (AV block, ventricular tachydysrhythmias, asystole, and sinus arrest), arterial embolism, fever, thrombocytopenia, hypotension, and anaphylactic reactions. *** this drug should be given PO as this decreases risk of cardiovascular reactions.
What is Lidocaine Which class? What are some CNS toxicity signs/interventions?
Lidocaine: Class I B antidysrhythmic drug.
CNS adverse effects: Drowsiness, constipation, and paresthesias. Toxic levels: may produce seizures and respiratory arrest. If toxicity persists, the rate of dosage would be slowed.
Which class of antidysrhythmic does propranolol, verapamil, and diltiazem belong? Why must one be extra cautious when giving these two classes of drugs together?
Propranolol: Class II Beta blocker
Verapamil: Class IV Calcium channel blocker
Diltiazem: Class IV Calcium channel blocker
**caution needs to be exercised as these classes each have adverse reactions that include heart failure and AV block.
What class of drug is Amiodarone? What are its serious side effects?
Amiodarone is a class III antidysrhythmic drug that is used to treat both atrial and ventricular dysrhythmias
Pulmonary toxicity: hypersensitivity, pneumonitis, interstitial/alveolar pneumonitis, pulmonary fibrosis.
Cardiotoxicity: HF, atrial and ventricular dysrhythmias, liver toxicity, thyroid toxicity, optic neuropathy, corneal microdeposits, toxicity in pregnancy and breast feeding. Dermatologic effects.
Cardio/Pulm: toxicities show up earlier than the others.
What is an adverse effect of all the antidysrhythmic drugs? Do some of these drugs increase mortality in some patients?
An adverse effect of all dysrhythmias is tha tthey all can worsen existing dysrhythmias and create new ones. Many of these drugs may actually double the risk of mortality in patients who have had myocardial infarctions. (CAST study)
