Is it appropriate to give scheduled hydralazine with a blood pressure reading of 139/57?

Hydralazine Should Not Be Given for Blood Pressure of 139/57

Scheduled hydralazine should not be administered with a blood pressure reading of 139/57 as this blood pressure is not elevated and hydralazine could cause harmful hypotension. 1

Assessment of Blood Pressure Reading

• The blood pressure reading of 139/57 mmHg does not meet criteria for hypertension according to current guidelines, as it is below the threshold of 140/90 mmHg 1
• The diastolic reading of 57 mmHg is actually low and indicates potential risk for hypotension if blood pressure is further reduced 1
• This blood pressure does not qualify as a hypertensive urgency (which requires diastolic BP >120 mmHg) or hypertensive emergency (which requires evidence of acute target organ damage) 2

Risks of Administering Hydralazine at This Blood Pressure

• Hydralazine is a direct vasodilator that can cause significant blood pressure reduction, with effects beginning within 10-30 minutes and lasting 2-4 hours 1
• Administration at this blood pressure level could lead to symptomatic hypotension, which was the most common adverse event reported in studies of inappropriate hydralazine use 3
• Hydralazine has unpredictable response and prolonged duration of action, making it unsuitable for use in non-urgent situations, especially with borderline or normal blood pressure 1

Appropriate Use of Hydralazine

• Hydralazine is indicated for:

  • Hypertensive emergencies when administered intravenously (initial 10 mg via slow IV infusion) 1
  • As a step 5 agent in resistant hypertension management (25 mg three times daily, titrated upward) 1
  • In combination with isosorbide dinitrate for heart failure with reduced ejection fraction 1

• Hydralazine is not recommended as a first-line agent for acute treatment in most patients due to:

  • Unpredictability of response 1
  • Prolonged duration of action 1
  • Risk of reflex tachycardia 1, 4

Evidence Against "As-Needed" Hydralazine Use

• A retrospective study found that 36% of PRN (as-needed) antihypertensive administrations were given for SBP <180 mmHg and DBP <110 mmHg, which is below the threshold for acute severe hypertension 5
• Another study found that intravenous hydralazine is commonly prescribed for non-urgent cases of hypertension in hospitalized patients, with 17% of patients experiencing adverse events, most commonly hypotension 3
• Changes in blood pressure after hydralazine administration are highly variable and related to baseline blood pressure values, making outcomes unpredictable 3, 6

Recommended Approach

• For a blood pressure of 139/57 mmHg:

  • Withhold scheduled hydralazine as this could worsen the already low diastolic pressure 1, 3
  • Monitor blood pressure for trends rather than treating a single reading 1
  • If the patient is on scheduled hydralazine for another indication (such as heart failure), consult with the prescribing physician about temporarily holding the dose 1
  • Consider evaluation for causes of low diastolic pressure if this is a persistent finding 1

• For patients with true hypertension requiring treatment:

  • Follow a stepwise approach to hypertension management as outlined in guidelines 1
  • Reserve hydralazine for specific indications such as resistant hypertension or hypertensive emergencies 1