Class III antiarrhythmics (potassium channel blockers) — Flashcards

Flashcard 1: Cardiovascular (Antiarrhythmics) _____, a class III antiarrhythmic, has many neurologic side effects (e.g. tremor, ataxia, peripheral neuropathy, sleep disturbances)

Answer: Amiodarone

Flashcard 2: What adverse effect is common to sotalol, dofetilide, and ibutilide (class III antiarrhythmics)? _____

Answer: Torsades de pointes

Flashcard 3: What effect do class III antiarrhythmics have on effective refractory period?_____

Answer: Increased ERP

Flashcard 4: _____ is a class III anti-arrhythmic that can produce hyper or hypothyroidism.

Answer: Amiodarone

Flashcard 5: What effect do class III antiarrhythmics have on action potential duration?_____

Answer: Increased AP duration

Flashcard 6: Amiodarone, a class III antiarrhythmic, can induce _____, especially with rapid IV administration

Answer: heart block

Flashcard 7: vardenafil

Answer: PDE5 inhibitor

Extra: erectile dysfunctionpatients taking nitrates (lethal hypotension)inhbit phosphodiesterase 5, resulting in increased cGMP and smooth muscle relaxation in corpus cavernosumheadache, flushing, impaired blue-green color vision, hypotension, dyspepsia

Flashcard 8: sildenafil

Answer: PDE5 inhibitor

Extra: erectile dysfunctionpatients taking nitrates (lethal hypotension)inhbit phosphodiesterase 5, resulting in increased cGMP and smooth muscle relaxation in corpus cavernosumheadache, flushing, impaired blue-green color vision, hypotension, dyspepsia

Flashcard 9: What is the effect of high-dose Aspirin (salicylates) on oxidative phosphorylation?

Answer: Uncouples oxidative phosphorylation (increases permeability of the inner mitochondrial membrane)

Extra: Aspirin (salicylates) in high doses uncouples oxidative phosphorylation, leading to a decreased ATP production and increased heat production (fever). It also contributes to the metabolic acidosis seen in salicylate toxicity.

Flashcard 10: Mechanism of action of Ouabain?

Answer: Inhibits Na+/K+-ATPase by binding to the K+ binding site

Extra: Ouabain is a cardiac glycoside (similar to digoxin) that binds to the extracellular side of the Na+/K+-ATPase pump, competing with Potassium (K+). This leads to increased intracellular Na+, which in turn decreases the activity of the Na+/Ca2+ exchanger, resulting in increased intracellular Ca2+ and positive inotropy.