Source / episode info

• **Episode:**255
• **Title:**Divine Intervention Episode 255 – The Legendary Step 2CK/3 Pharmacology Podcast.
• **Published:**2020-08-16
• Source:Episode page

One-liner

This episode provides a comprehensive review of major pharmacological classes tested on USMLE/COMLEX, covering antiplatelet agents (Aspirin, P2Y12 inhibitors), anticoagulants (Warfarin, DOACs), cardiovascular drugs (ACEi, ARBs, Beta-blockers, CCBs), and renal physiology (Loop vs Thiazide diuretics).

High-yield summary

• Antiplatelets: Aspirin irreversibly inhibits COX-1, preventing the formation of thromboxane A2 ({TXA}_2), thereby inhibiting platelet aggregation. P2Y12 inhibitors block ADP receptors.
• Anticoagulation Bridging: When initiating Warfarin therapy (a Vitamin K antagonist), bridging with unfractionated heparin is mandatory because natural anticoagulants like Protein C and Protein S have shorter half-lives than Factors II and X, creating a temporary hypercoagulable state.
• ACE Inhibitors (ACEi): Used for CHF and HTN; they are contraindicated in bilateral renal artery stenosis due to the risk of acute kidney injury. Side effects include dry cough (due to bradykinin accumulation) and angioedema; ARBs can be used as alternatives.
• Beta-blockers: Used extensively for rate control in Atrial Fibrillation (AFib). In a patient intoxicated with cocaine, an alpha blocker must be administered before a beta blocker to prevent severe hypertension/stroke.
• Diuretics Comparison: Loop diuretics inhibit the {Na}^+-{K}^+-2{Cl}^- cotransporter in the thick ascending limb (TAL) and are associated with hypocalcemia and hypercalciuria; Thiazides inhibit {Na}^+/{Cl}^- cotransporter in the DCT and are associated with hypercalcemia and hypocalciuria.
• Digoxin Toxicity: Digoxin inhibits the {Na}^+/{K}^+ ATPase pump, causing hyperkalemia as a side effect; toxicity risk is significantly increased when the patient is already hypokalemic due to increased binding sites on the pump.

Learning objectives

• Differentiate the mechanisms of action and clinical uses of antiplatelet agents (Aspirin, P2Y12 inhibitors).
• Understand the principles of anticoagulation management, including bridging protocols for Warfarin initiation.
• Compare and contrast the side effects and indications of major cardiovascular drug classes (ACEi, ARBs, Beta-blockers, CCBs).
• Analyze renal tubular physiology to distinguish between Loop and Thiazide diuretics regarding electrolyte balance (\text{Ca}^{2+}, \text{K}^+) and nephrolithiasis risk.
• Recognize the clinical implications of drug interactions, such as Digoxin toxicity in hypokalemia or Alpha blocker use with cocaine intoxication.