Can hydralazine (oral antihypertensive medication) 10mg (by mouth) twice a day (po bid) be stopped abruptly?

Can Hydralazine 10mg PO BID Be Stopped Abruptly?

No, hydralazine should not be stopped abruptly—it must be tapered gradually over 1-2 weeks while maintaining concurrent beta-blocker and diuretic therapy to prevent rebound hypertension. 1, 2

Why Abrupt Discontinuation Is Dangerous

Hydralazine causes significant physiologic changes that persist during withdrawal, making abrupt cessation risky:

• Increased sympathetic tone and reflex tachycardia occur with hydralazine use and can worsen dramatically upon sudden withdrawal 3, 1, 2
• Sodium and water retention induced by hydralazine persists during the discontinuation period 3, 1, 2
• Rebound hypertension is well-documented when antihypertensive medications, including hydralazine, are stopped abruptly 4

The 2017 ACC/AHA guidelines explicitly state that hydralazine is "associated with sodium and water retention and reflex tachycardia; use with a diuretic and beta blocker" 3, underscoring that these compensatory mechanisms must be managed during discontinuation.

Required Safeguards Before and During Discontinuation

Essential Concurrent Medications

You must ensure the patient is on both of the following before tapering hydralazine:

• Beta-blocker therapy (preferably metoprolol succinate or similar) to counteract the increased sympathetic tone that occurs during hydralazine withdrawal 1, 2
• Diuretic therapy to address ongoing sodium retention that persists even as hydralazine is being discontinued 1, 2

Critical warning: Never discontinue a beta-blocker at the same time as hydralazine, as abrupt beta-blocker cessation itself causes severe rebound hypertension 3, 2, 5

Tapering Protocol

• Taper gradually over 1-2 weeks rather than stopping abruptly 1, 2
• For a patient on 10mg BID (20mg total daily), consider reducing to 10mg once daily for 5-7 days, then discontinuing 1, 2
• Do not reduce diuretic therapy during the taper, as sodium retention persists 2

Monitoring Requirements

Implement close blood pressure surveillance throughout the discontinuation process:

• Check blood pressure every 2-3 days during the taper period 2
• Continue monitoring for one week after complete discontinuation to detect delayed rebound hypertension 2
• Home blood pressure monitoring is strongly recommended if available 2

Common Pitfalls to Avoid

• Stopping hydralazine without a beta-blocker on board: This allows unopposed sympathetic activation and dramatically increases rebound risk 1, 2
• Discontinuing the beta-blocker simultaneously: This compounds the risk of severe rebound hypertension 2, 5
• Reducing diuretic therapy during the taper: Sodium retention continues and requires ongoing diuretic management 1, 2
• Inadequate monitoring: Rebound hypertension may not manifest immediately and requires vigilant follow-up 2, 4

Context: When Hydralazine Discontinuation Is Appropriate

Hydralazine is typically reserved as 5th or 6th-line therapy in resistant hypertension 2. Discontinuation may be considered when:

• Blood pressure is well-controlled on other agents 2
• The patient is experiencing adverse effects (drug-induced lupus occurs at doses >150mg daily) 3, 1, 2
• Medication regimen simplification is needed 2

However, even in these scenarios, the tapering protocol and monitoring requirements remain unchanged.