PEBC MCQ study guide: Renal & Genitourinary Disorders

Providing Care – Clinical Care

Chronic kidney disease, renal drug dosing, and common genitourinary conditions.

Chronic Kidney Disease

KDIGO's 2024 CKD guideline reinforces ACE inhibitors/ARBs as foundational therapy for CKD with albuminuria (proteinuria reduction, slows progression independent of blood pressure effect), and now positions SGLT2 inhibitors as an additional foundational pillar for CKD with albuminuria (with or without diabetes) — a major expansion of SGLT2 inhibitor use beyond diabetes/heart failure into nephrology-driven indications, based on trials showing slowed progression to kidney failure.

Finerenone (a nonsteroidal mineralocorticoid receptor antagonist) is a newer add-on option for CKD with type 2 diabetes and albuminuria, providing further cardiorenal protection on top of ACE inhibitor/ARB and SGLT2 inhibitor therapy.

Staging combines eGFR category (G1–G5) with albuminuria category (A1–A3) — the combination, not eGFR alone, determines risk category and monitoring/referral intensity. NSAIDs should be avoided/minimized in CKD (reduce renal perfusion via afferent arteriole vasoconstriction, worsen the very albuminuria the other therapies are trying to reduce).

Renal Drug Dosing Principles

Loading doses generally do NOT require adjustment for renal impairment (volume of distribution is largely unaffected) — only maintenance doses/intervals need adjustment, since it's clearance, not distribution, that renal impairment affects. Renally-cleared drugs requiring common dose/interval adjustment on the exam: most antibiotics (aminoglycosides, vancomycin, many beta-lactams), DOACs, metformin, gabapentin/pregabalin, and digoxin.

Nephrotoxic drug combinations to flag: NSAID + ACE inhibitor/ARB + diuretic ("triple whammy" — significantly raises acute kidney injury risk, especially with volume depletion); vancomycin + aminoglycoside (additive nephrotoxicity); and contrast dye in patients with reduced eGFR (hold metformin around contrast administration per current renally-based guidance, rather than a fixed universal 48-hour rule).

Genitourinary Conditions

Benign prostatic hyperplasia (BPH): alpha-1 blockers (tamsulosin, alfuzosin) provide rapid symptomatic relief by relaxing prostatic smooth muscle; 5-alpha-reductase inhibitors (finasteride, dutasteride) shrink prostate volume over months and are more useful for larger prostates/long-term risk reduction — combination therapy is used for larger glands with bothersome symptoms. Alpha-blockers cause orthostatic hypotension and "floppy iris syndrome" (relevant to cataract surgery — inform the surgeon).

Overactive bladder: antimuscarinics (oxybutynin, solifenacin) or the beta-3 agonist mirabegron are first-line; antimuscarinics carry significant anticholinergic burden and are used cautiously in the elderly (Beers-listed), where mirabegron is often preferred.

High-yield points

KDIGO 2024: SGLT2 inhibitors are now foundational CKD therapy for albuminuric CKD (with or without diabetes), alongside ACE inhibitor/ARB.
Loading doses don't need renal adjustment — only maintenance dose/interval does.
"Triple whammy" (NSAID + ACEi/ARB + diuretic) significantly raises AKI risk.
Alpha-blockers (tamsulosin) cause floppy iris syndrome — flag before cataract surgery.
Antimuscarinics for overactive bladder are Beers-listed — mirabegron often preferred in older adults.

Guideline references

KDIGO 2024 Clinical Practice Guideline for CKD
Canadian Urological Association Guidelines