How should I taper a continuous intravenous nitroglycerin infusion running at 5 mL/hr (≈1 mg/hr) in a stable, symptom‑free patient with systolic blood pressure ≥90 mm Hg and a heart rate that is not markedly bradycardic or tachycardic?

Tapering Intravenous Nitroglycerin from 5 mL/hr

Reduce the infusion by 5–10 mcg/min every 3–5 minutes while monitoring blood pressure continuously, then transition to oral or topical nitrates once the patient has been symptom-free for 12–24 hours. 1, 2

Pre-Taper Assessment

Before initiating any dose reduction, confirm the patient meets these criteria:

• Symptom-free for at least 12–24 hours with no chest pain, dyspnea, or other ischemic manifestations 1, 2
• Systolic blood pressure ≥110 mmHg in previously normotensive patients, or not more than 25% below baseline mean arterial pressure in hypertensive patients 1
• Heart rate stable without marked bradycardia (<50 bpm) or tachycardia (>100 bpm) 2, 3
• No active pulmonary congestion or ongoing ischemia 1

Do not attempt tapering if the patient has active ischemic symptoms, hypotension (SBP <90 mmHg), or hemodynamic instability. 1, 2

Stepwise Tapering Protocol

Step 1: Gradual Dose Reduction

Decrease the infusion rate by 5–10 mcg/min every 3–5 minutes while continuously monitoring blood pressure and heart rate. 1, 4 This mirrors the titration increments used during initiation but in reverse, minimizing the risk of rebound ischemia.

• Monitor blood pressure before each dose reduction to detect early signs of hemodynamic instability 2
• Watch for ECG changes because abrupt cessation has been associated with exacerbation of ischemic changes 1
• If symptoms recur during tapering, increase the dose back to the previous effective level and stabilize for several more hours before attempting another reduction 1

Step 2: Transition to Non-Parenteral Nitrates

Once the infusion rate is reduced to 10–20 mcg/min and the patient remains stable:

Switch to oral or topical nitrates using a non-tolerance-producing regimen (intermittent dosing with a nitrate-free interval). 1, 2 Options include:

• Isosorbide mononitrate 20 mg twice daily (with doses separated to allow a nitrate-free interval) 1
• Isosorbide dinitrate 5–80 mg two or three times daily 1
• Transdermal nitroglycerin patch 0.2–0.8 mg/hr applied for 12 hours daily, then removed for 12 hours to prevent tolerance 1, 5, 6

Apply the first dose of oral/topical nitrate 1–2 hours before discontinuing the IV infusion to ensure therapeutic overlap and avoid a nitrate-free gap that could precipitate rebound ischemia. 1

Critical Monitoring During Taper

Continuously monitor blood pressure and heart rate throughout the taper because tolerance may have developed during prolonged infusion, and abrupt withdrawal can unmask underlying hemodynamic instability. 2

• Measure vital signs before each dose reduction 2
• Observe for chest pain, dyspnea, or ECG changes that signal recurrent ischemia 1
• In patients with inferior-wall MI or right ventricular involvement, exercise extra caution because these patients are preload-dependent and may decompensate during nitrate withdrawal 2

Common Pitfalls and How to Avoid Them

Rebound Ischemia

Abrupt discontinuation of IV nitroglycerin has been associated with exacerbation of ischemic ECG changes. 1 Always use a graded reduction rather than stopping the infusion suddenly.

Tolerance After Prolonged Infusion

Tolerance to nitroglycerin's hemodynamic effects typically develops after 24 hours of continuous therapy. 1, 2, 5, 6 If the patient has been on the infusion for >24 hours, they may have required escalating doses to maintain efficacy. During tapering, this tolerance may persist, so monitor closely for breakthrough symptoms.

Inadequate Transition to Oral Therapy

Ensure the oral or topical nitrate is administered 1–2 hours before stopping the IV infusion to maintain therapeutic nitrate levels and prevent a gap in coverage. 1 Use a non-tolerance-producing regimen (intermittent dosing) to preserve long-term efficacy. 1, 2

Premature Tapering

Do not taper in patients who are not yet symptom-free or who remain hemodynamically unstable. 2 Attempting to wean too early increases the risk of recurrent ischemia or pulmonary edema.

Special Populations Requiring Extra Caution

• Right ventricular infarction or inferior-wall MI: These patients depend on adequate preload; nitrate withdrawal can precipitate hypotension and low cardiac output 2
• Renal dysfunction: Hypotension during tapering can worsen renal perfusion; monitor blood pressure closely 1
• Aortic stenosis: These patients may experience marked hypotension with any change in vasodilator therapy 1

Duration Considerations

In stabilized patients, IV nitroglycerin should generally be converted to a non-parenteral alternative within 24 hours to avoid tolerance and facilitate hospital discharge. 1 If the infusion has been running for >24–48 hours, tolerance is likely, and you may need to increase doses periodically during the taper to maintain symptom control. 1, 2