Should I add a calcium‑channel blocker (CCB) on the morning of surgery for a hypertensive adult who is already taking metoprolol?

Should You Add a Calcium Channel Blocker on the Morning of Surgery?

No, do not add a new calcium channel blocker on the morning of surgery for a patient already taking metoprolol—continue the metoprolol and avoid initiating any new antihypertensive agents perioperatively.

Key Principle: Continue Existing Beta-Blockers, Avoid New Medications

Patients already taking beta-blockers like metoprolol should continue them through the morning of surgery to prevent rebound hypertension and tachycardia 1, 2, 3. This is a Class I recommendation with strong evidence 1.

• Abruptly discontinuing beta-blockers causes potentially harmful rebound hypertension 2, 3
• Continuing metoprolol perioperatively reduces perioperative cardiac death and nonfatal MI (2.1% vs 6.0% in controls) 1

Why Not Add a CCB on the Morning of Surgery?

Adding a new antihypertensive medication on the morning of surgery is explicitly contraindicated:

• Initiating beta-blocker therapy (or by extension, any new antihypertensive) the night before or morning of non-cardiac surgery is not recommended (Class III recommendation) 1
• There is no evidence that perioperative initiation of calcium channel blockers provides benefit 1
• Starting new medications perioperatively increases unpredictable hemodynamic effects during anesthesia

Blood Pressure Thresholds for Proceeding with Surgery

Proceed with surgery if blood pressure is <180/110 mmHg while continuing current medications 1, 2, 3:

• Blood pressure <160/100 mmHg: Proceed without delay 1, 3
• Blood pressure 160-179/100-109 mmHg: Proceed but inform primary care 1
• Blood pressure ≥180/110 mmHg: Defer surgery for optimization 1, 2

Management of Existing CCBs

If the patient were already taking a CCB chronically, it should be continued through the morning of surgery 3, 4, 5:

• Continuing CCBs does not increase perioperative risk when used chronically 4, 5
• Stopping CCBs can cause rebound hypertension 5
• However, continuing ARB/CCB combinations may increase intraoperative hypotension requiring vasopressors 6

Postoperative CCB Use

CCBs may be restarted postoperatively as blood pressure rises, but this is a reactive rather than preemptive strategy 1:

• Resume antihypertensive medications when the patient can tolerate oral intake 7, 2
• Postoperative medication decisions should be made progressively on a case-by-case basis 1
• Avoid hypotension, which may worsen organ perfusion 1, 2

Critical Pitfalls to Avoid

• Never initiate new antihypertensive therapy on the morning of surgery 1
• Never discontinue beta-blockers abruptly 1, 2, 3
• Do not add medications without considering intraoperative hypotension risk 6
• Ensure adequate pain control, as inadequate analgesia can cause postoperative hypertension 1