Continue Home Losartan
You should advise this patient to continue his home losartan through the perioperative period for his total knee arthroplasty. There is no indication to add or substitute carvedilol (Coreg) in this clinical scenario.
Rationale for Continuing Losartan
While there has been historical debate about perioperating management of angiotensin receptor blockers (ARBs) like losartan, the evidence does not support routine discontinuation or substitution with beta-blockers in this patient:
No clear contraindication exists: This patient has well-controlled hypertension (BP 140/70), normal renal function (normal CMP), and stable hemodynamics (HR 75). These parameters suggest he tolerates losartan well 1, 2, 3.
ARB discontinuation remains controversial: While some older literature suggested withholding ARBs on the day of surgery due to hypotension risk 2, 4, 3, there is no high-quality evidence mandating discontinuation, and the decision "should be made on a case-by-case basis" 2. The 2024 AHA/ACC perioperative guidelines 5 do not recommend routine ARB discontinuation.
Losartan shows no adverse effects in TKA patients: A 2025 study specifically examining losartan in total knee arthroplasty patients found no difference in complications or outcomes compared to patients not taking losartan 6.
Why NOT Carvedilol (Coreg)?
There is absolutely no indication to initiate or add carvedilol in this patient:
Beta-Blocker Initiation is Harmful Perioperatively
The 2024 AHA/ACC guidelines explicitly state that initiating beta-blockers should be restricted to patients with clear long-term or acute indications (heart failure, history of CAD) 5. This patient has neither.
Timing matters critically: If beta-blockers must be initiated, they should be started ≥7 days before surgery, not in the immediate perioperative period 5. Starting beta-blockers on the day of surgery or within days is associated with increased mortality, hypotension, and stroke 5.
The POISE trial demonstrated harm: High-dose beta-blockers initiated immediately before surgery in beta-blocker-naïve patients showed a net increase in all-cause mortality despite modest MACE reduction 5.
Carvedilol-Specific Concerns
The FDA labeling for carvedilol highlights multiple concerns relevant to this patient 7:
Perioperative risks: "If treatment with COREG is to be continued perioperatively, particular care should be taken when anesthetic agents which depress myocardial function...are used" 7. This warning applies to continuing carvedilol in patients already on it—not initiating it.
Glycemic effects in pre-diabetes: While carvedilol had no adverse effect on HbA1c in one study 7, beta-blockers generally "may mask manifestations of hypoglycemia" and "may potentiate insulin-induced hypoglycemia" 7. In a pre-diabetic patient, introducing this risk perioperatively is unnecessary.
Hypotension risk: Carvedilol commonly causes "low blood pressure (which may cause dizziness or fainting)" 7, which would compound any intraoperative hypotension risk.
Practical Management
Continue losartan at the current dose through surgery. Monitor blood pressure and hemodynamics closely in the perioperative period, as with any antihypertensive medication. Be prepared to manage hypotension if it occurs (typically with fluids and vasopressors as needed), but this risk does not justify discontinuation or medication substitution in a stable patient 1, 3.
Key Pitfalls to Avoid
- Do not initiate beta-blockers perioperatively without clear cardiac indications (heart failure, recent MI, CAD requiring beta-blockade) 5.
- Do not discontinue losartan abruptly without a specific contraindication, as this may lead to rebound hypertension.
- Do not add unnecessary medications that increase polypharmacy and perioperative risk without evidence of benefit.