An older adult with an estimated glomerular filtration rate … | MyMerci
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Medication AdministrationPPT
Question
An older adult with an estimated glomerular filtration rate of 32 mL/min takes lisinopril and spironolactone. A new prescription for trimethoprim-sulfamethoxazole is received. Which action should the nurse take before the first dose?
1Hold the dose and contact the prescriber to review hyperkalemia risk, potassium monitoring, renal dosing, and an alternative.✓ Correct answer
2Administer the dose and add a potassium supplement because sulfonamide antibiotics increase urinary potassium loss.
3Give the dose with orange juice to improve absorption and offset the potassium-lowering effect of lisinopril.
4Discontinue lisinopril and spironolactone independently for the antibiotic course, then restart both at discharge.
Explanation
Trimethoprim can cause hyperkalemia, and the risk rises with renal insufficiency and concurrent potassium-raising drugs such as an ACE inhibitor and spironolactone. The nurse should pause the new dose and obtain a medication review that addresses indication, renal dosing, an alternative agent, and close potassium and kidney-function monitoring. Potassium supplementation is unsafe, and chronic cardiovascular medications are not independently stopped by the nurse.
Clinical reasoning This client has several converging hyperkalemia risks: reduced renal clearance, trimethoprim, ACE inhibition, and aldosterone antagonism. A normal baseline potassium value does not eliminate the risk after therapy begins.
Decision rule Before combining trimethoprim-sulfamethoxazole with potassium-raising therapy in renal impairment, clarify the regimen and establish potassium and renal-function surveillance.
Key concepts
Trimethoprim-associated hyperkalemia — An increase in serum potassium linked to trimethoprim, especially in renal impairment or with other potassium-raising drugs.
Additive drug risk — A medication hazard produced when several therapies and patient factors act in the same harmful direction.