What is the recommended initial dose of lisinopril (Angiotensin-Converting Enzyme Inhibitor) for an 89-year-old patient with a blood pressure of 174/78 and a past medical history (PMH) of supraventricular tachycardia (SVT)?

Initial Lisinopril Dosing for an 89-Year-Old with Hypertension and SVT

For an 89-year-old patient with a blood pressure of 174/78 mmHg and a history of SVT, the recommended initial dose of lisinopril is 2.5 mg once daily with gradual titration as tolerated.

Rationale for Low Initial Dose

The FDA label for lisinopril 1 recommends a standard initial dose of 10 mg once daily for hypertension in adults. However, several factors in this case warrant a more cautious approach:

1. Advanced Age: At 89 years old, this patient falls into the very elderly category (≥80 years) where guidelines recommend more conservative dosing.

2. Isolated Systolic Hypertension: The patient has a systolic BP of 174 mmHg with normal diastolic BP (78 mmHg), which is common in elderly patients.

3. Risk of Orthostatic Hypotension: Elderly patients are more susceptible to orthostatic hypotension with antihypertensive medications.

Guidelines Supporting This Approach

The 2024 European Society of Cardiology (ESC) guidelines 2 specifically recommend:

• More cautious initiation of antihypertensive therapy in patients aged ≥85 years
• Consideration of a single agent rather than combination therapy in very elderly patients
• Fixed-dose single-pill combinations are preferred when combination therapy is needed

The 2007 ESH/ESC guidelines 2 emphasize:

• Initial doses and subsequent dose titration should be more gradual in elderly patients
• Higher risk of undesirable effects in very old and frail subjects

Treatment Algorithm

1. Initial Dose: Start with 2.5 mg lisinopril once daily (half the recommended starting dose for elderly patients taking diuretics) 1

2. Monitoring:

   • Check blood pressure after 1-2 weeks
   • Monitor for orthostatic hypotension (measure BP in both sitting and standing positions)
   • Assess renal function and electrolytes within 1-2 weeks of initiation

3. Dose Titration:

   • If BP remains >150/90 mmHg (target for very elderly) 2 and no adverse effects, increase to 5 mg daily
   • Further titration should be gradual (every 2-4 weeks) to a maximum of 40 mg daily as tolerated

4. Target BP:

   • For patients ≥80 years, guidelines suggest a target of <150/90 mmHg 2
   • The 2024 ESC guidelines 2 recommend a systolic BP target of 120-129 mmHg if well tolerated, but using the "as low as reasonably achievable" (ALARA) principle if not well tolerated

Special Considerations for SVT

The patient's history of supraventricular tachycardia (SVT) does not contraindicate lisinopril use. ACE inhibitors like lisinopril do not typically exacerbate SVT and may be beneficial in patients with cardiovascular conditions.

If the patient experiences an acute SVT episode, management would typically involve:

• Vagal maneuvers
• Adenosine as first-line pharmacological therapy
• Calcium channel blockers (verapamil, diltiazem) as alternatives

Potential Pitfalls and Cautions

• Renal Function: Ensure renal function is assessed before starting therapy. If creatinine clearance is ≤30 mL/min, the initial dose should be reduced to 2.5 mg 1

• Orthostatic Hypotension: Monitor for symptoms like dizziness upon standing, especially after initial dosing

• Electrolyte Monitoring: Check potassium levels within 1-2 weeks of initiation as hyperkalemia can occur with ACE inhibitors

• Drug Interactions: Be cautious with concomitant use of potassium supplements, potassium-sparing diuretics, or NSAIDs

By starting with a low dose of 2.5 mg and gradually titrating based on BP response and tolerability, you can minimize adverse effects while effectively managing hypertension in this elderly patient.