Perioperative Medication Management for Open Appendectomy
Continue telmisartan, carvedilol, and levothyroxine on the morning of surgery; hold metformin on the day of surgery and restart when oral intake resumes. 1
Telmisartan (ARB) - Hold on Day of Surgery
While there is ongoing debate about ARB management, the safest approach is to hold telmisartan on the morning of surgery due to increased risk of intraoperative hypotension. ARBs and ACE inhibitors are the two exceptions to the general rule of continuing antihypertensives perioperatively 2. The drug label confirms telmisartan can cause symptomatic hypotension in volume-depleted states, which commonly occur during surgery 3.
- Restart telmisartan within 24-48 hours postoperatively once hemodynamically stable and oral intake established 4
- Monitor blood pressure closely during the perioperative period
- Ensure adequate volume status before anesthesia induction
Carvedilol (Beta-blocker) - Continue
Continue carvedilol 12.5 mg on the morning of surgery with a sip of water. This patient is already on chronic beta-blocker therapy, and abrupt discontinuation increases risk of rebound hypertension, tachycardia, and myocardial ischemia 1. The 2024 AHA/ACC guidelines emphasize that patients already taking beta-blockers should continue them perioperatively 1.
- The FDA label notes that if carvedilol is continued perioperatively, use caution with myocardial-depressant anesthetic agents 5
- Critical pitfall: Never initiate beta-blockers <7 days before surgery (associated with increased mortality), but this patient is already on chronic therapy 1
- Resume normal dosing schedule postoperatively
Metformin - Hold Day of Surgery
Hold metformin 500 mg on the day of surgery. The 2024 AHA/ACC guidelines state that continuation of metformin during the perioperative period is reasonable for glycemic control 1, but the practical approach for appendectomy (which may involve NPO status and potential bowel involvement) is to hold it the morning of surgery.
- Restart metformin when patient resumes normal oral intake and renal function is confirmed stable (typically postoperative day 1-2 for uncomplicated appendectomy)
- Check renal function if not done within 3 months 1
- Monitor for lactic acidosis risk factors (sepsis, hypoperfusion)
- Important: If patient were on SGLT2 inhibitors, those must be stopped 3-4 days before surgery to prevent perioperative ketoacidosis 1, but metformin does not carry this risk
Levothyroxine - Continue
Continue levothyroxine 50 mcg on the morning of surgery with a sip of water. Thyroid hormone has a long half-life (approximately 7 days), so missing a single dose has minimal clinical impact, but there is no reason to hold it 6.
- Resume normal dosing schedule immediately postoperatively
- Inadequately controlled hypothyroidism is associated with increased cardiovascular risk in diabetic patients 6
- No dose adjustment needed for surgery itself
Additional Perioperative Considerations
Glycemic monitoring: Check HbA1c if not done within 3 months 1. Target intraoperative glucose control, though optimal targets remain undefined 1.
Drug interactions: Monitor digoxin levels if patient is on it (carvedilol increases digoxin by 15%) 5. Carvedilol may enhance blood-sugar-lowering effects of metformin, requiring closer glucose monitoring 5.
Anesthesia coordination: Inform anesthesiologist about carvedilol continuation, as it may interact with myocardial-depressant anesthetic agents 5.
Blood pressure management: Expect potential hypotension from combined effects of ARB withdrawal, beta-blockade, and anesthesia. Have vasopressors readily available.