What testing and side effects should be assessed in a patient returning for recheck 6 weeks after starting lisinopril (Angiotensin-Converting Enzyme inhibitor)?

Testing and Side Effects Assessment for Lisinopril Follow-up at 6 Weeks

At the 6-week follow-up visit after starting lisinopril, renal function and serum electrolytes must be assessed, with particular attention to potassium levels and creatinine, while monitoring for common side effects including cough, hypotension, dizziness, and angioedema. 1

Laboratory Testing Required

Essential Tests

• Renal function

  • Serum creatinine (monitor for increases >50% from baseline or above 265 μmol/L [3 mg/dL]) 1
  • Blood urea nitrogen (BUN)
  • Estimated glomerular filtration rate (eGFR)

• Electrolytes

  • Serum potassium (critical to detect hyperkalemia >5.5 mmol/L) 1
  • Serum sodium (to detect hyponatremia)

Additional Tests to Consider

• Complete blood count (to monitor for small decreases in hemoglobin and hematocrit) 2
• Blood glucose in diabetic patients (ACE inhibitors may enhance hypoglycemic effects of antidiabetic medications) 2

Side Effects Assessment

High Priority Side Effects

1. Renal dysfunction

   • Increases in creatinine up to 50% from baseline or to an absolute value of 265 μmol/L (3 mg/dL) are acceptable 1
   • If creatinine rises above 265 μmol/L but below 310 μmol/L (3.5 mg/dL), halve the dose of lisinopril 1
   • If creatinine rises above 310 μmol/L (3.5 mg/dL), stop lisinopril immediately 1

2. Hyperkalemia

   • If potassium rises above 5.5 mmol/L, halve the dose of lisinopril 1
   • If potassium rises above 6.0 mmol/L, stop lisinopril immediately 1
   • Check for use of potassium supplements or potassium-sparing diuretics 1

3. Hypotension

   • Assess for symptoms like dizziness, light-headedness, or syncope 1
   • Measure blood pressure in both sitting and standing positions
   • Symptomatic hypotension often improves with time; reassure patient 1
   • Consider reducing dose of diuretics if hypotension is problematic 1

4. Persistent dry cough

   • A common side effect specific to ACE inhibitors 1
   • Document presence, severity, and impact on quality of life

5. Angioedema

   • Rare but potentially life-threatening reaction 1, 2
   • Assess for facial, lip, tongue, or throat swelling

Additional Side Effects to Monitor

• Fatigue or asthenia 2
• Headache
• Taste disturbances
• Rash or other dermatological manifestations 2
• Gastrointestinal symptoms (nausea, diarrhea, abdominal pain)

Dose Adjustment Considerations

1. If no adverse effects and blood pressure not at target:

   • Consider dose up-titration toward target dose (20-35 mg daily for lisinopril) 1
   • Recheck renal function and electrolytes 1 and 4 weeks after increasing dose 1

2. If adverse effects present:

   • For mild side effects: continue monitoring without dose change
   • For moderate side effects: consider dose reduction
   • For severe side effects: consider drug discontinuation

Patient Education Points to Review

• Importance of medication adherence
• Need for regular monitoring of kidney function and electrolytes
• Instructions to report symptoms of hypotension (dizziness, lightheadedness)
• Guidance to report any swelling of face, lips, tongue, or throat immediately
• Avoidance of NSAIDs which can worsen renal function 1
• Avoidance of potassium supplements or salt substitutes containing potassium 1

Common Pitfalls to Avoid

• Failure to check renal function and electrolytes - these are essential at the 6-week follow-up
• Missing hyperkalemia - can be life-threatening if severe and undetected
• Discontinuing medication due to expected minor increases in creatinine - small increases are expected and acceptable
• Ignoring drug interactions - particularly NSAIDs, potassium-sparing diuretics, and antidiabetic medications 2
• Overlooking non-adherence - assess if side effects are affecting compliance

Following this systematic approach to monitoring will help ensure safe and effective use of lisinopril while minimizing risks of serious adverse events.