Free CDN Pharmacology Practice Questions with Answers

The hypotension is likely due to the rate of infusion of labile or free iron. Rapid infusion of iron preparations can cause transient vasodilation and hypotension. Preventive Strategy: Slow the rate of administration. Ferric Gluconate should be administered at a rate not exceeding 12.5 mg/minute (e.g., 125mg over at least 10 minutes). Rationale: Unlike iron dextran, newer agents are more stable, but they still contain a small amount of labile iron that can cause vasomotor symptoms if pushed too quickly.

Sevelamer Hydrochloride (Renagel) can worsen metabolic acidosis because it exchanges chloride ions for phosphate, increasing the chloride load. Sevelamer Carbonate (Renvela) is the preferred alternative as it uses a carbonate buffer, which may help maintain or even increase serum bicarbonate levels. Clinical Pearl: Chronic acidosis contributes to bone resorption and muscle wasting; thus, Sevelamer Carbonate has become the standard in modern nephrology practice. Exam focus: Differentiating between the HCl and Carbonate formulations. Difficulty: Medium

The ESA dose should be reduced by at least 25%. A rise in Hb >1 g/dL in any 2-week period is considered too rapid and increases the risk of adverse CV events and hypertension. Clinical Pearl: Consistency is key; do not adjust doses more frequently than every 4 weeks unless the Hb rise is excessive. Exam Tip: NNCC frequently uses math-based scenarios where you must calculate a 25% reduction based on a provided dose.

The liver is the primary site for citrate metabolism into bicarbonate. In hepatic failure or hypoperfusion (shock), citrate clearance is severely reduced, leading to citrate accumulation and systemic hypocalcemia. This is often accompanied by a metabolic acidosis because the body cannot convert the citrate (an organic acid) into bicarbonate. Clinical Pearl: In these patients, the Total Calcium will rise significantly while Ionized Calcium drops. This is a common distractor; liver failure causes citrate accumulation, not necessarily immediate alkalosis.

Dextrose-based solutions utilize both the small pores and ultrasmall pores (aquaporin-1) for water transport. The high osmotic pressure of dextrose is the main driver for aquaporin-mediated transport (free water clearance). Icodextrin, due to its colloid nature, moves fluid primarily through the small pores and does NOT significantly utilize aquaporins. This is why Icodextrin is effective in patients with diminished aquaporin function but preserved small-pore transport.