What is the recommended initial treatment for a new patient with newly diagnosed hypertension, normal potassium and serum creatinine levels, and no other significant past medical history?

Prescription for Newly Diagnosed Hypertension

For a newly diagnosed hypertensive patient with normal labs and no comorbidities, prescribe lisinopril 10 mg once daily and hydrochlorothiazide 12.5 mg once daily as separate tablets for a 30-day supply. 1

Rationale for Starting Doses

Lisinopril Dosing

• The FDA-approved initial dose for hypertension is 10 mg once daily, which represents the standard starting point for monotherapy 1
• When used in combination with a diuretic, the FDA label recommends starting at 5 mg once daily 1
• However, since you are prescribing these as separate medications (not initiated simultaneously), start with lisinopril 10 mg once daily 1

Hydrochlorothiazide Dosing

• Start with 12.5 mg once daily, which is the low-dose thiazide recommended by multiple guidelines 2
• This dose provides effective blood pressure reduction while minimizing metabolic side effects 3, 4
• The 12.5 mg dose is equipotent to 25 mg for blood pressure control but has fewer adverse metabolic effects on potassium, glucose, and lipids 4

Prescription Format

Prescription #1:

• Lisinopril 10 mg tablets
• Sig: Take 1 tablet by mouth once daily
• Dispense: 30 tablets
• Refills: 0 (requires follow-up for titration)

Prescription #2:

• Hydrochlorothiazide 12.5 mg tablets
• Sig: Take 1 tablet by mouth once daily
• Dispense: 30 tablets
• Refills: 0 (requires follow-up for titration)

Guideline Support for This Approach

First-Line Drug Classes

• Both ACE inhibitors and thiazide-like diuretics are recommended first-line agents for hypertension 2, 5
• The combination of an ACE inhibitor plus thiazide diuretic is specifically endorsed for initial therapy in stage 2 hypertension 2, 5

Combination Therapy Rationale

• Multiple-drug therapy is generally required to achieve blood pressure targets 2
• Starting with two agents from different classes is recommended for patients with blood pressure ≥160/100 mmHg (stage 2 hypertension) 2
• The combination of lisinopril and hydrochlorothiazide produces greater blood pressure reduction than either agent alone 6, 4

Critical Monitoring Requirements

Laboratory Monitoring

• Monitor serum creatinine, eGFR, and potassium levels at least annually 2
• Recheck these labs within 2-4 weeks after initiation to detect early adverse effects 2
• The combination may cause hyperkalemia (from lisinopril) or hypokalemia (from hydrochlorothiazide), though these effects often balance each other 6, 4

Blood Pressure Monitoring

• Schedule monthly follow-up visits until target blood pressure (<130/80 mmHg) is achieved 5
• Use home blood pressure monitoring for medication titration 5
• Target blood pressure should be achieved within 3 months 2

Common Pitfalls to Avoid

Dosing Errors

• Do not start lisinopril at 5 mg when prescribing separately—this lower dose is only recommended when initiating both drugs simultaneously or in patients already on diuretics 1
• Avoid hydrochlorothiazide 25 mg as initial dose—this higher dose increases metabolic side effects without additional blood pressure benefit 3, 4

Metabolic Considerations

• Hydrochlorothiazide 12.5 mg causes minimal changes in glucose, potassium, and lipids compared to 25 mg 3, 4
• Lisinopril attenuates some adverse metabolic effects of hydrochlorothiazide when used in combination 7, 8
• The 12.5 mg dose of hydrochlorothiazide had borderline blood pressure effects alone but is highly effective when combined with an ACE inhibitor 3, 4

Titration Strategy

• If blood pressure remains uncontrolled after 2-4 weeks, increase lisinopril to 20 mg once daily before increasing hydrochlorothiazide 1
• The usual maintenance dose range for lisinopril is 20-40 mg daily 1
• Doses of hydrochlorothiazide above 12.5 mg provide minimal additional benefit and increase side effects 4

Expected Adverse Effects

Most Common Side Effects

• Dizziness (7.5%), headache (5.2%), cough (3.9%), and fatigue (3.7%) are the most frequent adverse effects with this combination 7
• Cough is specifically related to lisinopril and occurs in approximately 4% of patients 7, 4
• Orthostatic effects occur in 3.2% of patients—counsel patient to rise slowly from sitting or lying positions 7

Serious Adverse Effects to Monitor

• Angioedema (rare but serious complication of ACE inhibitors) 1
• Acute kidney injury, particularly in patients with bilateral renal artery stenosis 1
• Hyperkalemia when combined with potassium supplements or potassium-sparing diuretics 2