Pharmacology

Question 1

What are the four classes of antiarrhythmic medications?

Which phase of the cardiac action potential does each class work on?

Answer 1

• Class I: Na+ Channel Blockers (use has declined due to their proarrhythmic effects, esp in pt with ischemic heart disease and or heart failure)
• Class II: Ca2+ Channel Blockers
• Class III: K+ Channel Blockers (all have potential to induce dysrhythmias)
• Class IV: Beta-Blockers

Question 2

Why should antiarrhythmic medications (other than beta blockers and calcium channel blockers) be prescribed by a cardiologist rather than you?

Answer 2

Bc I’m just a kid, and life is a nightmare

Require intensive monitoring, several side effects, proarrhythmic actions (can prolong QT interval)

Question 3

1. What are the adverse effects of amiodarone (Class III)?

Answer 3

• Pulmonary fibrosis (fatal in 1% of pts)
• Blue-gray skin discoloration (<3% of pts undergoing chronic therapy)
• Hypo- or hyperthyroidism
• Corneal deposits
• Optic neuritis
• Hepatotoxicity

Question 4

What are the adverse effects of digoxin?

Answer 4

At toxic concentrations, causes ectopic ventricular beats that may result in VT and ventricular fibrillation (serum trough concentrations 1.0-2.0 ng/mL)

Question 5

Class IA: Quinidine side effects

Answer 5

Cinchonism – Blurred vision, tinnitus, HA, disorientation, psychosis.

Question 6

Class III: Sotalol side effects

Answer 6

Proarrhythmic. Initiation in hospital is required to monitor QT interval

Question 7

What condition is severe hypertriglyceridemia associated with?

Answer 7

Acute pancreatitis

Question 8

What is the Friedewald equation?

Answer 8

• LDL is calculated by this equation if triglycerides <400 mg/dL
• LDL = total cholesterol – HDL – triglycerides/5
• When triglycerides are not elevated, this equation is sufficiently accurate.

Question 9

What is hypercholesterolemia versus combined hyperlipidemia versus hypertriglyceridemia?

Answer 9

• Hypercholesterolemia: Triglycerides <176 mg/dL (LDL is main atherogenic component in plasma)
• Combined hyperlipidemia: Triglycerides 176-999 mg/dL (LDL, IDL, chylomicron remnants, and VLDL combined constitute the atherogenic plasma component)
• Hypertriglyceridemia: Triglycerides >999 mg/dL

Question 10

What are the different classes of medications for hyperlipidemia and hypertriglyceridemia?

Answer 10

• HMG-CoA reductase inhibitors – Statins
• Intestinal absorption inhibitors – Ezetimibe (Zetia)
• Bile acid-binding resins – Cholestyramine
• PCSK9 inhibitors – Alirocumab (Praluent) + Evilocumab (Repatha)
• Omega-3 fatty acids – Lovaza 4 g/day
• Niacin– Niaspan 2g max/day
• Fibrates – Fenofibrate + Gemfibrozil