What is the recommended initial dose and monitoring protocol when initiating lisinopril (angiotensin-converting enzyme inhibitor) for patients with hypertension or heart failure?

Initiating Lisinopril for Hypertension and Heart Failure

For patients with hypertension, lisinopril should be initiated at 10 mg once daily, while heart failure patients should start at 5 mg once daily (or 2.5 mg if hyponatremic), with monitoring of blood pressure, renal function, and electrolytes 1-2 weeks after initiation and after each dose increase. 1, 2

Initial Dosing

Hypertension

• Initial dose: 10 mg once daily 1
• If patient is already taking diuretics: 5 mg once daily 1
• Usual maintenance range: 20-40 mg once daily 1
• Maximum dose: 40 mg daily (doses up to 80 mg have been used but provide minimal additional benefit) 1

Heart Failure

• Initial dose: 5 mg once daily 1, 3
• For patients with hyponatremia (serum sodium <130 mEq/L): 2.5 mg once daily 1
• Target dose: 20-40 mg once daily 3
• Mean doses achieved in clinical trials: 32.5-35 mg daily 3

Dose Titration Protocol

1. Start with appropriate initial dose based on indication
2. Double the dose at intervals of not less than 2 weeks 3, 2
3. Aim for target dose or highest tolerated dose 3
4. Remember: some ACE inhibitor is better than no ACE inhibitor 3

Monitoring Protocol

Initial Monitoring

• Check blood pressure, renal function (creatinine), and electrolytes (especially potassium) 5-7 days after starting treatment 3, 2
• Recheck every 5-7 days until potassium values are stable 3

Follow-up Monitoring

• Monitor 1-2 weeks after each dose increase 3, 2
• Once at maintenance dose: check at 3 months, then every 6 months 2
• Monitor for:
  • Blood pressure response
  • Renal function (creatinine)
  • Electrolytes (especially potassium)
  • Symptoms of adverse effects

Special Considerations

Renal Impairment

• For creatinine clearance >30 mL/min: no dose adjustment required 1
• For creatinine clearance 10-30 mL/min: reduce initial dose by half
  • Hypertension: 5 mg once daily
  • Heart failure: 2.5 mg once daily 1
• For hemodialysis or creatinine clearance <10 mL/min: initial dose 2.5 mg once daily 1

Precautions Before Initiating

• Review need for and dose of diuretics 3
• Consider reducing or withholding diuretics for 24 hours before starting lisinopril 3
• Avoid potassium-sparing diuretics during initiation 3
• Avoid NSAIDs and COX-2 inhibitors 3

Managing Common Issues

Hypotension

• Asymptomatic hypotension usually doesn't require therapy change 3
• For symptomatic hypotension:
  • Consider reducing diuretic dose if no signs of congestion 3
  • If hypotension occurs after initial dose, it doesn't preclude continued therapy after effective management 1

Worsening Renal Function

• Some increase in creatinine is expected and acceptable
• An increase in creatinine of up to 50% above baseline, or to 3 mg/dL, whichever is greater, is acceptable 3
• If renal function deteriorates substantially, stop treatment 3

Cough

• Cough is common in heart failure patients and may be due to pulmonary edema rather than ACE inhibition 3
• ACE inhibitor-induced cough rarely requires treatment discontinuation 3
• If troublesome cough develops and is proven to be due to ACE inhibition, consider substituting an angiotensin receptor blocker 3

Contraindications

• History of angioedema
• Pregnancy
• Bilateral renal artery stenosis 2
• Significant renal dysfunction (creatinine >2.5 mg/dL or >221 μmol/L) - seek specialist advice 3
• Hyperkalemia (>5.0 mmol/L) - seek specialist advice 3
• Symptomatic or severe asymptomatic hypotension (systolic BP <90 mmHg) - seek specialist advice 3

By following this structured approach to initiating lisinopril, clinicians can optimize the benefits of ACE inhibition while minimizing potential adverse effects in patients with hypertension or heart failure.