Should a patient with low blood pressure take their diltiazem?

Should This Patient Take Their Diltiazem with BP 115/60?

Yes, the patient should take their diltiazem unless they are experiencing symptoms of hypotension (dizziness, lightheadedness, confusion). A blood pressure of 115/60 mmHg represents asymptomatic low blood pressure, which does not require medication adjustment according to heart failure guidelines 1.

Key Decision Point: Symptomatic vs Asymptomatic Hypotension

The critical distinction is whether the patient has symptoms:

• Asymptomatic low blood pressure (115/60 without symptoms): Continue diltiazem as prescribed 1
• Symptomatic hypotension (with dizziness, lightheadedness, confusion): Reconsider need for diltiazem and other vasodilators 1

The European Society of Cardiology explicitly states that "asymptomatic low blood pressure does not usually require any change in therapy" 1. This guidance applies to calcium channel blockers like diltiazem when used for rate control or blood pressure management.

Clinical Context and Reasoning

Diltiazem's primary indications matter here:

• If prescribed for atrial fibrillation rate control, the heart rate is more important than blood pressure 1
• If prescribed for hypertension, a BP of 115/60 is actually within target range (target <130/80 mmHg per 2020 ISH guidelines) 1
• If prescribed for angina, symptom control takes precedence over absolute BP numbers 2

The FDA label contraindicates diltiazem only when systolic BP is less than 90 mmHg 3. At 115/60, this patient is well above the absolute contraindication threshold.

What to Monitor

Before taking the dose, the patient should assess for:

• Dizziness or lightheadedness when standing 1
• Confusion or altered mental status 1
• Signs of worsening heart failure (if applicable): increased shortness of breath, weight gain, edema 1
• Heart rate if on concurrent beta-blockers (risk of excessive bradycardia) 1

When to Hold or Adjust Diltiazem

Hold the dose and contact the prescriber if:

• Symptomatic hypotension develops (dizziness, lightheadedness, confusion with low BP) 1
• Heart rate drops below 50 bpm with worsening symptoms 1
• New or worsening signs of heart failure appear 1

For symptomatic hypotension management:

• First reconsider other vasodilators (nitrates, other calcium channel blockers) 1
• If no signs of fluid overload, consider reducing diuretic dose 1
• Only after these steps should diltiazem dose reduction be considered 1

Common Pitfalls to Avoid

Do not reflexively hold diltiazem based solely on a BP number. The 2012 ESC Heart Failure Guidelines emphasize that asymptomatic low blood pressure is common and expected with appropriate cardiovascular medication dosing 1. Unnecessarily holding medications can lead to:

• Loss of rate control in atrial fibrillation
• Return of anginal symptoms
• Rebound hypertension (though less concerning with diltiazem than beta-blockers) 4

The blood pressure of 115/60 is not inherently dangerous and may represent optimal cardiovascular protection, particularly if the patient is on diltiazem for hypertension management where targets are <130/80 mmHg 1.

Special Considerations

If the patient is also taking beta-blockers: Exercise extra caution, as the combination increases risk of bradycardia and hypotension 1, 2. Check heart rate before dosing.

If the patient has heart failure with reduced ejection fraction: Diltiazem should generally be avoided due to negative inotropic effects 1, 3, but if already prescribed, asymptomatic low BP alone is not a reason to stop 1.

Elderly or frail patients: May be more susceptible to symptomatic hypotension even at higher BP readings, so symptom assessment is particularly important 1.