JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD Pharm. D II Year PHARMACOTHERAPEUTICS-I Previous Question Paper (October/November - 2020 - R08)

The Joint National Committee (JNC 8) report provides evidence-based guidelines for the management of hypertension in adults. Key highlights include:

• Treatment Thresholds: For the general population aged 60 years or older, pharmacologic treatment is initiated at a systolic blood pressure (SBP) of 150 mmHg or higher or a diastolic blood pressure (DBP) of 90 mmHg or higher, with a goal of < 150/90 mmHg.
• General Population < 60: The treatment threshold is set at 140/90 mmHg, with a goal of < 140/90 mmHg.
• Comorbidities: In patients with diabetes or chronic kidney disease (CKD), the threshold and goal are set at < 140/90 mmHg regardless of age.
• Drug Selection: For the non-black population, initial therapy should include a thiazide-type diuretic, calcium channel blocker (CCB), angiotensin-converting enzyme inhibitor (ACEI), or angiotensin receptor blocker (ARB).
• Black Population: Initial therapy should include a thiazide-type diuretic or CCB.
• CKD Management: ACEIs or ARBs are recommended for all patients with CKD to improve kidney outcomes, regardless of race or diabetes status.
• Combination Therapy: The report advises against combining an ACEI with an ARB and suggests titration or adding a second drug if the goal is not reached within one month.

The electrophysiology of the heart involves the generation and conduction of electrical impulses that coordinate cardiac contraction. This process is driven by the movement of ions across the myocardial cell membranes.

• Resting Membrane Potential: Myocardial cells maintain a negative resting potential (approx. -90 mV) primarily due to high intracellular potassium concentration and the activity of the Na+/K+-ATPase pump.
• Action Potential Phases: The ventricular action potential consists of five phases:
  • Phase 0 (Depolarization): Rapid influx of Na+ ions through fast voltage-gated channels, causing the membrane potential to become positive.
  • Phase 1 (Initial Repolarization): Inactivation of Na+ channels and brief outward flow of K+.
  • Phase 2 (Plateau): Sustained depolarization due to the influx of Ca2+ through L-type channels, balancing the outward K+ current. This phase is critical for excitation-contraction coupling.
  • Phase 3 (Rapid Repolarization): Closure of Ca2+ channels and massive efflux of K+ through delayed rectifier channels, returning the cell to its resting state.
  • Phase 4 (Resting Phase): Maintenance of the resting membrane potential.
• Conduction System: The impulse originates in the SA node (pacemaker), travels through the atria to the AV node (where it is delayed to allow ventricular filling), and then spreads rapidly through the Bundle of His and Purkinje fibers to trigger ventricular contraction.