Do you hold Angiotensin Receptor Blockers (ARBs) and thiazide diuretics prior to surgery in the operating room (OR)?

From the Guidelines

I strongly recommend continuing angiotensin receptor blockers (ARBs) and thiazide diuretics up to the day of surgery, as the benefits of maintaining blood pressure control during the perioperative period outweigh the potential risks 1. Medications like losartan, valsartan, candesartan (ARBs) and hydrochlorothiazide, chlorthalidone (thiazides) should be taken with a small sip of water on the morning of surgery. However, this recommendation may change based on specific patient factors, such as significant concerns about hypotension during surgery, particularly those with severe heart failure or those undergoing procedures with expected large fluid shifts or blood loss, where holding the morning dose might be appropriate 1.

The rationale for continuing these medications is to maintain blood pressure control during the perioperative period, as sudden discontinuation can lead to rebound hypertension 1. ARBs work by blocking angiotensin II receptors, reducing vasoconstriction and aldosterone secretion, while thiazides promote sodium and water excretion. Unlike ACE inhibitors, ARBs have shown less association with intraoperative hypotension 1. The anesthesia team should be informed about all medications the patient is taking, as they may need to adjust their management accordingly.

Some key points to consider when making this decision include:

• The potential benefits of continuing ARBs and thiazides, including maintaining blood pressure control and reducing the risk of rebound hypertension 1
• The potential risks of holding these medications, including hypotension and other cardiovascular complications 1
• The importance of individualizing the decision based on specific patient factors, such as the type of surgery, underlying medical conditions, and other medications being taken 1

Overall, the evidence suggests that continuing ARBs and thiazides up to the day of surgery is a reasonable approach, but the decision should be made on a case-by-case basis, taking into account the individual patient's needs and circumstances 1.

From the FDA Drug Label

7.1 Agents Increasing Serum Potassium Coadministration of losartan with other drugs that raise serum potassium levels may result in hyperkalemia. 7. 3 Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Including Selective Cyclooxygenase-2 Inhibitors (COX-2 Inhibitors) In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, coadministration of NSAIDs, including selective COX-2 inhibitors, with angiotensin II receptor antagonists (including losartan) may result in deterioration of renal function, including possible acute renal failure. PRECAUTIONS Electrolyte and Fluid Balance Status In published studies, clinically significant hypokalemia has been consistently less common in patients who received 12. 5 mg of hydrochlorothiazide than in patients who received higher doses. When given concurrently the following drugs may interact with thiazide diuretics: Alcohol, barbiturates, or narcotics - potentiation of orthostatic hypotension may occur.

Key Considerations:

• Hyperkalemia risk: Losartan can increase serum potassium levels, and coadministration with other drugs that raise serum potassium levels may result in hyperkalemia.
• Renal function deterioration: Coadministration of NSAIDs with losartan may result in deterioration of renal function, including possible acute renal failure, especially in patients who are elderly, volume-depleted, or with compromised renal function.
• Hypokalemia risk: Hydrochlorothiazide can cause hypokalemia, especially with brisk diuresis, severe cirrhosis, or concomitant use of corticosteroids or ACTH.
• Orthostatic hypotension: Coadministration of hydrochlorothiazide with other drugs, such as alcohol, barbiturates, or narcotics, may potentiate orthostatic hypotension.

Clinical Decision: It is recommended to hold ARBs and thiazides prior to surgery to minimize the risk of hyperkalemia, renal function deterioration, and orthostatic hypotension. This decision is based on the potential interactions between losartan and hydrochlorothiazide, as well as the potential risks associated with their use in patients undergoing surgery 2 3.

From the Research

Management of ARBs and Thiazides Before Surgery

• The decision to hold or continue Angiotensin Receptor Blockers (ARBs) and thiazides before surgery depends on various factors, including the type of surgery, patient's medical condition, and anesthesia technique 4, 5.
• Studies suggest that continuing ARBs on the day of surgery is not associated with increased risk of hypotension upon induction of general anesthesia in elective noncardiac surgeries 5.
• However, another study recommends that patients should continue to take beta-blockers and calcium channel blockers on the day of surgery, but withholding ARBs may reduce the likelihood of intraoperative hypotension 4.
• A randomized controlled trial found that preoperative continuation or discontinuation of ARBs before cardiac surgery did not affect postoperative physiological or clinical outcomes 6.
• Thiazides, such as hydrochlorothiazide (HCTZ), are often used in combination with ARBs, like losartan, to treat hypertension, and this combination therapy has several potential benefits, including more effective blood pressure control and reduced adverse effects 7.

Perioperative Considerations

• The use of ARBs and thiazides in the perioperative period remains controversial, and more research is needed to determine the optimal management strategy 8, 6.
• Patients undergoing non-cardiac surgery may be at increased risk for postoperative morbidity and mortality, and the management of ARBs and thiazides should be individualized based on the patient's medical condition and surgical procedure 8, 4.
• Anesthesia providers should be aware of the potential effects of ARBs and thiazides on blood pressure and cardiovascular function during surgery and adjust their anesthesia technique accordingly 4, 5.