Can patients take beta blockers and hydralazine before surgery?

Perioperative Management of Beta Blockers and Hydralazine

Yes, patients should continue beta blockers before surgery if they are already taking them chronically, and hydralazine can be used perioperatively for specific indications such as eclampsia/preeclampsia or acute hypertensive emergencies, but the management approach differs significantly between these two medications. 1

Beta Blocker Management

For Patients Already on Beta Blockers

• Continue beta blockers in all patients who are on them chronically - this is a Class I recommendation with strong evidence, as abrupt discontinuation causes severe harm including exacerbation of angina, myocardial infarction, and ventricular arrhythmias. 1

• Never abruptly discontinue beta blockers perioperatively - this is classified as Class III: Harm, meaning it is potentially harmful and should be avoided. 1

• The FDA drug labels for metoprolol and atenolol explicitly warn: "Chronically administered beta-blocking therapy should not be routinely withdrawn prior to major surgery" and "severe exacerbation of angina, myocardial infarction and ventricular arrhythmias have been reported in patients with coronary artery disease following the abrupt discontinuation of therapy with beta-blockers." 2, 3

• Titrate beta blockers perioperatively based on hemodynamics, but ensure continuation through hospital stay and at discharge unless clear contraindications arise (severe bradycardia <60 bpm, hypotension with SBP <100 mmHg, second- or third-degree heart block, acute pulmonary edema). 1

For Beta Blocker-Naïve Patients

• Do not start beta blockers on the day of surgery - this is Class III: Harm based on the POISE trial, which demonstrated increased all-cause mortality, stroke, and hypotension when high-dose beta blockers were initiated immediately before surgery. 1

• If beta blocker initiation is deemed necessary before surgery, begin at least 7 days before surgery (preferably >1 day minimum, optimally >31 days) to assess safety and tolerability, as initiating <7 days before surgery is associated with higher mortality risk. 1

• Starting beta blockers perioperatively in patients without established indications (heart failure, coronary artery disease) is not recommended, as the POISE trial showed that potential benefits (moderate reduction in MACE) were offset by harms (hypotension, stroke, increased mortality). 1

Hydralazine Management

Specific Perioperative Indications

• Hydralazine is specifically recommended for eclampsia or preeclampsia as a first-line agent for rapid blood pressure lowering in this population, where ACE inhibitors, ARBs, renin inhibitors, and nitroprusside are contraindicated. 1

• For perioperative hypertension (BP ≥160/90 mmHg or SBP elevation ≥20% of preoperative value persisting >15 minutes), other IV agents are preferred over hydralazine, including clevidipine, esmolol, nicardipine, or nitroglycerin. 1

• Hydralazine can cause reflex tachycardia and increased inotropic effect, so beta blockers or other agents may be needed for BP control when using hydralazine. 1

Chronic Hydralazine Use

• If a patient is chronically taking hydralazine for hypertension, it is reasonable to continue it perioperatively as part of the general principle that antihypertensive medications should be continued until surgery. 1

• However, for intraoperative hypertensive emergencies, IV formulations of clevidipine, nicardipine, or esmolol are preferred over hydralazine due to more predictable pharmacokinetics and easier titration. 1

Critical Pitfalls to Avoid

• Never stop beta blockers abruptly - this creates rebound hypertension, tachycardia, and acute coronary syndromes that are far more dangerous than any theoretical surgical risk. 1, 2, 3

• Never start beta blockers on the day of surgery in beta blocker-naïve patients - the POISE trial definitively showed this increases mortality. 1

• Do not confuse hydralazine with other vasodilators - it has specific indications (eclampsia/preeclampsia) where it is preferred, but for general perioperative hypertension, other IV agents are superior. 1

• Be aware that beta blockers mask tachycardia from hypoglycemia in diabetic patients, though other manifestations like dizziness and sweating remain. 2, 3

• The impaired ability of the heart to respond to reflex adrenergic stimuli when on beta blockers may augment risks of general anesthesia, but this does not justify discontinuation - instead, be prepared to manage bradycardia and hypotension with appropriate interventions. 2, 3

Postoperative Management

• Resume beta blockers immediately postoperatively and ensure they are continued at discharge - guide management by clinical circumstances including hemodynamics. 1

• If hydralazine was used for acute perioperative hypertension, transition to oral antihypertensive regimen as soon as the patient can tolerate oral medications. 1