Is renal high yield on the PEBC exam?

Yes, and more than it looks. Beyond dedicated chronic kidney disease and acute kidney injury questions, renal drug dosing is woven through almost every other therapeutic area, so being comfortable adjusting doses by kidney function pays off across the whole exam.

What renal topics should I focus on for the PEBC?

Focus on chronic kidney disease management and its complications, the common causes of acute kidney injury, renal drug dosing and the major nephrotoxins, and electrolyte disorders. Being able to adjust a dose by creatinine clearance or eGFR is the single most transferable skill.

Which guidelines should I use for renal on the PEBC?

The standard references are the KDIGO guidelines for chronic kidney disease and acute kidney injury, which are the internationally and Canadian-accepted standard. For dosing, work from the renal adjustment information in your drug references.

How should I study renal for the PEBC?

Get fast at adjusting doses by creatinine clearance and eGFR, memorize the common nephrotoxins and the drugs to avoid in chronic kidney disease, and learn the common electrolyte-drug links.

PEBC Renal Practice Questions

Renal is a deceptively high-yield area on the PEBC exam, because renal drug dosing shows up inside almost every other topic, not just in dedicated kidney questions. Chronic kidney disease, acute kidney injury, electrolyte disorders, and dose adjustment by kidney function all matter.

Below is a sample drawn from those areas. The reasoning covers every option, not just the right one, so the kidney-function detail that settled the question is on the page.

Written and reviewed against current Canadian guidelines and references.

free questions here

no signup to start

All 4

options explained

How to approach a PEBC renal question

1Check kidney function first. Many questions test whether you adjust the dose or avoid the drug entirely at a given creatinine clearance or eGFR.
2Know the drugs that need renal dose adjustment and the ones to avoid in chronic kidney disease, including the metformin eGFR thresholds, several antibiotics, and NSAIDs.
3For electrolytes, match the abnormality to its cause and the responsible drug, such as high potassium with ACE inhibitors, ARBs, and spironolactone.
4Anchor on the KDIGO guidelines for chronic kidney disease and acute kidney injury.
5Watch for nephrotoxins and the patient who is on several interacting kidney-risk drugs at once.

Practice questions

Tap an answer to see why each option is right or wrong.

Question 1AKI

A 64-year-old male admitted 4 days ago has had his SCr rise from a baseline of 92 µmol/L to 168 µmol/L (1.8× baseline). Urine output is 0.55 mL/kg/h. He has not yet started renal replacement therapy. Which KDIGO AKI stage applies?

Incorrect · Answer: B

PEBC Yield: Highkdigo-stagingdiagnosis-classification

Stage 3 requires SCr ≥3× baseline OR SCr ≥354 µmol/L OR initiation of RRT (in pediatrics, eGFR <35 mL/min/1.73 m²). None of these are present.

B) (Correct)

Correct. KDIGO Stage 1 captures SCr 1.5-1.9× baseline within 7 days OR a ≥26.5 µmol/L rise in 48 hours. The patient's 1.8× rise falls within Stage 1. Urine output of 0.55 mL/kg/h is above the 0.5 oliguria threshold and does not upstage the patient. Key point: KDIGO stages use the WORSE of SCr or urine output criteria — always check both axes, then take the higher stage.

Stage 2 requires SCr 2.0-2.9× baseline. The patient's 1.8× rise hasn't reached this threshold.

Stage 1 SCr criteria are met when SCr rises ≥26.5 µmol/L in 48 h OR is 1.5-1.9× baseline within 7 days. This patient's SCr is 1.8× baseline — clearly within Stage 1 SCr criteria. The AKI is staged, not unstaged.

Question 2AKI

A 70-year-old with AKI has K⁺ 5.6 mmol/L (controlled with insulin/dextrose), pH 7.32, urine output 25 mL/h responding to furosemide, and no encephalopathy. Which clinical finding, if present, would MOST clearly indicate the need for urgent renal replacement therapy?

Incorrect · Answer: A

PEBC Yield: Highrrt-indicationsaeiou

A) (Correct)

Correct. Volume overload refractory to maximum-dose IV diuretic therapy is the 'O' in AEIOU and a primary RRT indication. Pulmonary edema unresponsive to IV furosemide 120 mg in a patient with AKI means the kidney can no longer offload the volume — dialysis is required. Key point: AEIOU = Acidosis (pH <7.1 refractory), Electrolyte (K+ >6.5 refractory or with ECG changes), Intoxication (dialyzable toxins — methanol, ethylene glycol, salicylates, lithium, metformin), Overload (refractory pulmonary edema), Uremia (symptomatic). Memorize these five — they're the universally accepted RRT triggers.

Mild peripheral edema in a hemodynamically stable patient does not meet 'refractory volume overload' criteria. Diuretics, fluid restriction, and observation are appropriate first.

SCr 2.5× baseline meets KDIGO Stage 2 AKI criteria but is not, by itself, an RRT trigger. RRT timing is based on clinical complications (AEIOU), not creatinine level alone — early prophylactic RRT has not been shown to improve outcomes.

Asymptomatic uremia is NOT an RRT trigger. The 'U' in AEIOU specifically requires SYMPTOMATIC uremia — encephalopathy, pericarditis, or bleeding from platelet dysfunction. Isolated urea elevation without symptoms can usually be observed.

Question 3AKI

A resident proposes initiating low-dose dopamine in a 68-year-old with AKI and oliguria to improve renal perfusion. Per KDIGO recommendations, which is the MOST appropriate response?

Incorrect · Answer: B

PEBC Yield: Highkdigo-recommendationsvasopressors

Titrating dopamine to a urine output goal misses the underlying issue: low-dose dopamine transiently increases urine output without improving GFR or any patient-oriented outcome. The increased urine flow is not protective.

B) (Correct)

Correct. KDIGO explicitly recommends AGAINST low-dose ('renal-dose') dopamine for AKI prevention or treatment. Despite older teaching that low-dose dopamine selectively dilates renal vasculature, multiple trials have shown no improvement in clinical outcomes (mortality, RRT need) and demonstrated harm (arrhythmias, mesenteric vasoconstriction). Norepinephrine is the preferred vasopressor when one is needed. Key point: 'renal-dose dopamine' is a classic PEBC distractor — KDIGO's explicit recommendation against this practice is a high-frequency exam point.

Low-dose dopamine is not preferred when BP is stable but oliguria persists. The correct approach is to optimize volume status with crystalloid, then use norepinephrine if hemodynamic support is needed.

Giving dopamine before fluid resuscitation skips the most important AKI prevention step. Volume status must be addressed first; pressors only after adequate volume challenge.

Question 4AKI

A 58-year-old with septic shock and developing AKI requires volume resuscitation. The ICU has hydroxyethyl starch (HES), 0.9% NaCl, Ringer's lactate, and isotonic sodium bicarbonate available. Which fluid should be AVOIDED per KDIGO guidance?

Incorrect · Answer: C

PEBC Yield: Highkdigofluid-selection

Isotonic sodium bicarbonate is an acceptable alternative to NS, particularly when CI-AKI prevention or concurrent metabolic acidosis correction is also desired.

0.9% NaCl (normal saline) is the standard isotonic crystalloid for resuscitation and is fully appropriate in AKI risk and sepsis.

C) (Correct)

Correct. KDIGO recommends AGAINST hydroxyethyl starch (HES) in patients at risk for AKI or with sepsis. Three landmark trials — VISEP (2008), 6S (2012), and CHEST (2012) — showed HES is associated with increased AKI incidence and increased need for RRT compared to crystalloid. Health Canada subsequently restricted HES use. Key point: HES is on the AVOID list for AKI risk; isotonic crystalloid is the universal first-line resuscitation fluid.

Ringer's lactate is a balanced isotonic crystalloid recommended by KDIGO for resuscitation and is fully appropriate.

Question 5CKD

A 64-year-old with CKD Stage 4 and T2DM has been on dapagliflozin 10 mg daily for 18 months. He is not on dialysis, tolerates the drug well, and has had a 40% reduction in albuminuria. His eGFR has gradually declined to 17 mL/min/1.73 m². Which action regarding dapagliflozin is MOST appropriate per KDIGO 2024?

Incorrect · Answer: A

PEBC Yield: Highsglt2idrug-selectionkdigo-2024

A) (Correct)

Correct. KDIGO 2024 practice point: once initiated, SGLT2i should be CONTINUED even if eGFR falls below the 20 mL/min/1.73 m² initiation threshold. The cardiorenal benefit (slowed kidney disease progression, reduced HF hospitalizations) persists at low eGFR. Discontinuation is reserved for dialysis initiation, transplant, or intolerance. This patient has a 40% ACR reduction — clearly benefiting — so continuation is appropriate. Key point: SGLT2i initiation threshold (eGFR ≥20) differs from continuation threshold (no lower limit until dialysis) — this distinction is high-yield PEBC; trials like DAPA-CKD and EMPA-KIDNEY established the continuation rule.

Dose reduction is not recommended for SGLT2i in CKD — they're given at fixed doses regardless of eGFR (dapagliflozin 10 mg daily; empagliflozin 10 mg daily; canagliflozin 100 mg daily for renal indication). Reducing the dose attenuates cardiorenal benefit without safety advantage.

Switching to empagliflozin doesn't change the continuation rule — all SGLT2i agents (dapagliflozin, empagliflozin, canagliflozin) share the same KDIGO recommendation. There's no tolerability advantage specific to empagliflozin at low eGFR.

Discontinuing at eGFR 17 misapplies the 20 mL/min INITIATION rule to a patient already on therapy. Once started, SGLT2i should continue regardless of eGFR decline.

Question 6CKD

A pharmacist initiates ramipril 5 mg daily in a CKD Stage 3b patient (eGFR 36). Two weeks later, eGFR is 28 (a 22% drop). Serum potassium is 4.8 mmol/L. Which action is MOST appropriate?

Incorrect · Answer: A

PEBC Yield: Highaceimonitoring

A) (Correct)

Correct. KDIGO accepts an initial eGFR dip of up to 30% on ACEi/ARB initiation as expected hemodynamic adjustment — efferent arteriole dilation reduces intraglomerular pressure, which is the renoprotective mechanism. With 22% drop AND stable potassium (4.8 within normal), the medication should continue. Recheck labs in 4-6 weeks for stabilization. Key point: the 30% rule is one of the most testable PEBC concepts — DON'T stop ACEi/ARB for predictable hemodynamic eGFR drops; DO stop for >30% drop, hyperkalemia >5.5, or symptomatic hypotension.

Switching to amlodipine abandons the proteinuria-reducing benefit of RAAS blockade. The eGFR drop is expected and acceptable — switching agents is unnecessary.

Adding a potassium binder is unnecessary when K+ is 4.8 (well within normal). Binders (patiromer, sodium zirconium cyclosilicate) are reserved for K+ >5.5 mmol/L preventing ACEi/ARB continuation.

Discontinuing ramipril over a 22% eGFR drop abandons the renoprotective effect prematurely. KDIGO accepts up to 30% initial eGFR decline as expected hemodynamic adjustment — the drop IS the drug working (efferent dilation lowering intraglomerular pressure).

Question 7CKD

A 72-year-old male with atrial fibrillation and CKD Stage 4 (eGFR 24) needs oral anticoagulation. He weighs 75 kg with SCr 195 µmol/L. Which DOAC is MOST appropriate for this patient?

Incorrect · Answer: B

PEBC Yield: Highdoacanticoagulationdrug-selection

Dabigatran is ~80% renally excreted and accumulates significantly at CrCl <30. Contraindicated in CKD Stage 4 due to substantial bleeding risk — the half-life can double, leading to unpredictable anticoagulation depth.

B) (Correct)

Correct. Apixaban is the preferred DOAC in advanced CKD because of its LOWEST renal elimination (~27%) and the LARGEST body of safety data at low eGFR. Standard dose is 5 mg BID; reduce to 2.5 mg BID if ≥2 of: age ≥80, weight ≤60 kg, SCr ≥133 µmol/L. For this patient, the SCr criterion is met (195) but only one criterion total, so 5 mg BID is appropriate. Key point: in CKD-AF, the DOAC hierarchy is apixaban > rivaroxaban > dabigatran > edoxaban — apixaban's low renal clearance and AUGUSTUS/ARISTOTLE trial data give it the strongest position at advanced CKD.

Rivaroxaban 20 mg daily is the standard AF dose for CrCl ≥50. At this patient's CrCl ~24, the dose would need to be reduced to 15 mg daily, but rivaroxaban has less robust safety data at advanced CKD than apixaban.

Edoxaban requires CrCl 15-50 for use, but it has substantially less long-term safety data in advanced CKD than apixaban. Apixaban remains the preferred first choice.

Question 8Electrolyte Disorders

Which patient is at HIGHEST risk for osmotic demyelination syndrome during sodium correction?

Incorrect · Answer: A

PEBC Yield: Highosmotic-demyelinationhyponatremia

A) (Correct)

Correct. The highest ODS risk combines all four major risk factors: chronic hyponatremia (Na 110, well below the 120 threshold), alcohol use disorder, malnutrition, and hypokalemia. Each independently amplifies ODS risk; together they multiply — alcohol and malnutrition impair brain osmolyte recovery, hypokalemia worsens cerebral edema during correction. Maximum correction rate must be strictly limited to <8 mEq/L per 24 hours (some sources say <6) in this profile. Key point: ODS risk factors mnemonic — Chronic hyponatremia + Alcohol + Malnutrition + Potassium depletion (CAMP); presence of all four flags the most aggressive correction limits.

Acute hyponatremia (developed within 48 hours, as in exercise-associated hyponatremia) has very low ODS risk because the brain has not yet adapted to low sodium by exporting organic osmolytes. Rapid correction is actually preferred for acute symptomatic hyponatremia — the brain can quickly re-equilibrate.

Chronic hyponatremia with sodium 115 from SIADH is a real ODS risk if corrected too quickly, but this patient is well-nourished with normal potassium — missing the major risk multipliers (alcohol, malnutrition, hypokalemia). Risk is moderate but not highest.

Acute hyponatremia (developed within 24 hours, even with loop diuretic) carries low ODS risk because the brain has not had time to adapt. Rapid correction is appropriate for acute symptomatic cases.

Question 9Electrolyte Disorders

A 52-year-old presents with Na 112 mmol/L, witnessed seizure, and ongoing confusion. The medical team plans urgent treatment with 3% NaCl. Which initial dose is MOST appropriate?

Incorrect · Answer: D

PEBC Yield: Highhyponatremiahypertonic-saline

1 L of 3% NaCl over 1 hour would massively over-correct serum sodium and cause severe ODS. This volume of hypertonic saline is never appropriate.

500 mL of 3% NaCl over 30 minutes risks rapid over-correction (>10-12 mEq/L in 24h) and osmotic demyelination syndrome. Hypertonic saline boluses are deliberately small and titrated to symptoms.

50 mL of 3% NaCl is below the recommended bolus volume — it would raise serum sodium by only ~1 mEq/L, insufficient to reverse cerebral edema in seizure-level symptomatic hyponatremia.

D) (Correct)

Correct. Severe symptomatic hyponatremia (seizure, coma, or severely altered mental status) is treated with 3% NaCl 100 mL IV bolus over 10 minutes, which may be repeated once if symptoms persist after 10 minutes. This raises serum sodium by approximately 2-4 mEq/L safely without overshooting the 8-10 mEq/L per 24h correction ceiling. Key point: the 100 mL × 10 min bolus protocol is the universal hypertonic saline emergency dose — small enough to avoid over-correction, large enough to reverse cerebral edema in symptomatic patients.

Question 10Electrolyte Disorders

A patient with hypokalemia (K+ 2.9 mmol/L) has received 80 mEq of oral potassium chloride over 24 hours with minimal response. Mg level is 0.55 mmol/L (normal 0.7-1.0). Which is the MOST appropriate next step?

Incorrect · Answer: C

PEBC Yield: Highhypokalemiahypomagnesemiadrug-selection

Continuing oral KCl 40 mEq twice daily and waiting will continue to produce poor results — Mg deficiency impairs the ROMK potassium channel in the renal collecting duct, driving ongoing renal potassium wasting regardless of replacement dose. The K+ replacement is being lost faster than it's being absorbed.

Switching to IV potassium without first addressing magnesium will also fail because the renal wasting persists. IV potassium is reserved for severe hypokalemia (K+ <2.5) or when oral is not tolerated — not as a workaround for magnesium-driven loss.

C) (Correct)

Correct. In refractory hypokalemia with concurrent hypomagnesemia, magnesium must be repleted FIRST (typical: IV magnesium sulfate 2 g over 1 hour) before potassium replacement can be effective. Mg deficiency impairs renal K+ retention via ROMK channel inhibition — the channel that normally returns secreted K+ to the blood. With Mg low, K+ leaks out into the urine continuously, and oral K+ supplementation just feeds the leak. Replace Mg, then K+ retention restores. Key point: 'Mg before K' is one of the most testable PEBC nephrology pearls — refractory hypokalemia ALWAYS prompts a Mg level check; correcting Mg often restores K+ within 24 hours without aggressive supplementation.

Adding spironolactone treats the symptom (renal K loss) rather than the cause (Mg deficiency). It also introduces its own risks (hyperkalemia paradoxically once Mg is corrected, gynecomastia) and is not the canonical solution to refractory hypokalemia.

Want the full bank?

These are a sample. The full bank adds full-length cases and timed mock exams.

Frequently asked questions

Is renal high yield on the PEBC exam?: Yes, and more than it looks. Beyond dedicated chronic kidney disease and acute kidney injury questions, renal drug dosing is woven through almost every other therapeutic area, so being comfortable adjusting doses by kidney function pays off across the whole exam.
What renal topics should I focus on for the PEBC?: Focus on chronic kidney disease management and its complications, the common causes of acute kidney injury, renal drug dosing and the major nephrotoxins, and electrolyte disorders. Being able to adjust a dose by creatinine clearance or eGFR is the single most transferable skill.
Which guidelines should I use for renal on the PEBC?: The standard references are the KDIGO guidelines for chronic kidney disease and acute kidney injury, which are the internationally and Canadian-accepted standard. For dosing, work from the renal adjustment information in your drug references.
How should I study renal for the PEBC?: Get fast at adjusting doses by creatinine clearance and eGFR, memorize the common nephrotoxins and the drugs to avoid in chronic kidney disease, and learn the common electrolyte-drug links.