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Difficulty: MediumPharmacologic Interventions

A 62-year-old woman is evaluated in the ambulatory care clinic for a post-hospital discharge follow-up. Four days ago, she was discharged after a 3-day hospitalization for a non-ST-segment elevation myocardial infarction (NSTEMI). During her hospitalization, she underwent percutaneous coronary intervention with the placement of a drug-eluting stent in the right coronary artery. Her medical history is significant for type 2 diabetes mellitus, gastroesophageal reflux disease, and stage 4 chronic kidney disease.

Current medications include:
* Aspirin 81 mg daily
* Clopidogrel 75 mg daily
* Metoprolol succinate 50 mg daily
* Lisinopril 20 mg daily
* Atorvastatin 80 mg daily
* Metformin 1000 mg twice daily
* Omeprazole 40 mg daily

Laboratory studies obtained today show:

TestResult
Serum sodium138 mEq/L
Serum potassium4.6 mEq/L
Blood urea nitrogen34 mg/dL
Serum creatinine2.3 mg/dL (baseline 2.2 mg/dL)
Estimated glomerular filtration rate24 mL/min/1.73 m²
Hemoglobin A1c7.8%

Which of the following pharmacologic interventions are indicated for this patient at this time? (Select all that apply)

  1. Discontinue metforminAnswer
  2. Replace omeprazole with pantoprazoleAnswer
  3. C
    Initiate spironolactone
  4. D
    Decrease the dose of atorvastatin to 20 mg daily
  5. E
    Discontinue lisinopril

Answer

The correct interventions are to discontinue metformin and replace omeprazole with pantoprazole.
This patient requires two immediate pharmacologic adjustments. First, metformin must be discontinued because her estimated glomerular filtration rate (eGFR) is less than 30 mL/min/1.73 m2, placing her at a high risk for metformin-associated lactic acidosis. Second, omeprazole should be replaced with an alternative acid-suppressing agent, such as pantoprazole or a histamine H2-receptor antagonist. Omeprazole is a strong inhibitor of the cytochrome P450 2C19 (CYP2C19) enzyme, which is required to convert clopidogrel into its active antiplatelet metabolite. Concurrent use of omeprazole and clopidogrel reduces the efficacy of clopidogrel and increases the risk of major adverse cardiovascular events, including stent thrombosis. Pantoprazole does not significantly inhibit CYP2C19 and is a safer alternative.

Step-by-Step Solution

1
Review the patient's renal function against her current medication list.
The patient has an eGFR of 24 mL/min/1.73 m2. Metformin is contraindicated below an eGFR of 30 mL/min/1.73 m2.
Continuing metformin in advanced renal failure poses an unacceptably high risk for life-threatening lactic acidosis.
2
Evaluate the patient's post-myocardial infarction regimen for severe drug-drug interactions.
The patient is taking omeprazole alongside clopidogrel.
Omeprazole is a strong CYP2C19 inhibitor, which prevents clopidogrel from converting to its active antiplatelet metabolite, thereby increasing the risk of stent thrombosis. A safer agent like pantoprazole must be substituted.
3
Assess the appropriateness of other cardiac medications in the context of chronic kidney disease.
Atorvastatin requires no renal adjustment. Lisinopril is safe to continue given stable baseline creatinine and normokalemia. Spironolactone is contraindicated due to the eGFR < 30 mL/min/1.73 m2.
Recognizing the indications and contraindications for secondary prevention medications ensures optimal cardiac remodeling without precipitating iatrogenic harm.

Key Concept

Medication reconciliation and pharmacologic adjustments in chronic kidney disease and post-acute coronary syndrome.
Estimated Time:1m 30s
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Topics

Pharmacologic Interventions

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