Medication Management During Acute Kidney Injury

Medication management during acute kidney injury follows three actions: hold what harms or accumulates, adjust what is cleared by the kidney, and restart in a planned order once function recovers. A full medication chart review within 24 hours of diagnosis is usual practice.

Hold. ACE inhibitors, angiotensin receptor blockers, mineralocorticoid receptor antagonists, NSAIDs, metformin, SGLT2 inhibitors, lithium and, unless the patient is overloaded, diuretics.

Adjust. Gabapentinoids, enoxaparin, antibiotics and antivirals with renal clearance, opioids with active metabolites, and insulin and sulphonylureas, whose action lasts longer.

Continue. Beta blockers, aspirin, statins, most antiepileptic drugs (with dose review) and essential antimicrobials at full first dose.

Hyperkalaemia treatment. Potassium of 6.0 mmol/L or over, or any ECG change, needs immediate treatment.

• Calcium gluconate 10 percent, 10 mL intravenously over 5 to 10 minutes. Repeat after 5 to 10 minutes if ECG changes persist.

• Soluble insulin 10 units with glucose 25 g (50 mL of 50 percent dextrose) intravenously over 15 minutes. Use less insulin or more glucose if the starting glucose is low, and check glucose hourly for 6 hours.

• Salbutamol 10 to 20 mg nebulised over 10 minutes, as an addition.

• Sodium zirconium cyclosilicate 10 g orally three times daily for up to 48 hours to lower potassium.

• Sodium bicarbonate when there is metabolic acidosis, and a loop diuretic if the patient makes urine.

Fluid overload. Furosemide 40 to 80 mg intravenously, doubling the dose after 1 to 2 hours if response is poor, with an intravenous infusion for continued overload. No response in a patient with oliguria is an indication for dialysis.

Special groups.

• Children: dose by mg/kg.

• Pregnancy: avoid renin-angiotensin blockers and NSAIDs.

• Older adults: reduce insulin doses early.

• East Africa: severe malaria, sepsis, rhabdomyolysis and dehydration are frequent causes, so treat the cause with full doses of antimicrobials such as artesunate, which needs no kidney adjustment.

Restarting medicines.

• ACE inhibitor or angiotensin receptor blocker: restart when the patient is euvolaemic, blood pressure is adequate, potassium is under 5.5 mmol/L and creatinine is within about 20 to 30 percent of baseline. Restart at a low dose and recheck in 1 to 2 weeks.

• Metformin: restart when eGFR is stable and 30 or over, using a maximum of 1 g daily until eGFR is 45 or over.

• SGLT2 inhibitor: restart when eating and drinking normally and creatinine is stable.

• Diuretic: restart for fluid overload only.

• Enoxaparin: use 20 mg once daily for prophylaxis if clearance is under 30 mL/min, and increase as clearance recovers.

Monitoring. Record creatinine, potassium, urine output and weight daily. Review the chart daily and update each dose to current function.

Stop rules. Stop any drug that worsens creatinine, potassium or blood pressure after a restart, and hold restarts during recurrent illness.

Referral and escalation. Seek urgent nephrology advice for potassium 6.5 mmol/L or over, ECG changes unresponsive to treatment, pH under 7.2 persistently, refractory fluid overload, uraemic pericarditis or encephalopathy, and dialysable poisons.

Common errors. Giving insulin and glucose without hourly glucose checks, restarting an ACE inhibitor too soon, keeping metformin and NSAIDs on the chart, and under-treating sepsis because of kidney function.