From the Guidelines
Amlodipine should generally be continued preoperatively to prevent hypertension, not hypotension. Amlodipine, a long-acting calcium channel blocker, should be taken up to and including the morning of surgery. The usual adult dose ranges from 2.5 to 10 mg once daily. Abrupt discontinuation of amlodipine before surgery can lead to rebound hypertension, which poses greater surgical risks than continuing the medication. While calcium channel blockers can cause vasodilation and potentially contribute to hypotension during anesthesia, the risks of uncontrolled blood pressure from stopping the medication typically outweigh this concern. Anesthesiologists can manage any intraoperative hypotension with fluids and vasopressors as needed. It's essential to consider the most recent guidelines, such as the 2019 commentary on the 2017 ACC/AHA hypertension guideline 1, which suggests continuing medical therapy for hypertension until surgery. Although this guideline does not specifically address amlodipine, the principle of continuing antihypertensive medication to avoid rebound hypertension applies. Patients should inform their surgical team about all medications they're taking, and any decision to modify the regimen should be made in consultation with both the surgeon and the prescribing physician. The long half-life of amlodipine (30-50 hours) means that stopping it just before surgery wouldn't significantly reduce its effects anyway. Key points to consider include:
- Continuing amlodipine preoperatively to prevent rebound hypertension
- Managing potential intraoperative hypotension with appropriate measures
- Consulting with both the surgeon and the prescribing physician regarding any changes to the medication regimen
- Informing the surgical team about all medications being taken.
From the FDA Drug Label
5 WARNINGS AND PRECAUTIONS
5.1 Hypotension Symptomatic hypotension is possible, particularly in patients with severe aortic stenosis. Because of the gradual onset of action, acute hypotension is unlikely.
The FDA drug label does not answer the question.
From the Research
Amlodipine and Pre-Operative Hypotension
- Amlodipine is a calcium channel blocker that is often used to control blood pressure and relieve symptoms of angina pectoris 2.
- The decision to continue or withhold amlodipine pre-operatively depends on various factors, including the patient's medical condition, the type of surgery, and the anesthetic technique used.
Studies on Amlodipine and Hypotension
- A study published in the Middle East journal of anaesthesiology in 2013 reported a case of severe post-operative hypotension in a patient who was taking amlodipine for blood pressure control 3.
- Another study published in The Journal of clinical endocrinology and metabolism in 2021 found that preoperative amlodipine was efficacious in preventing intraoperative hemodynamic instability in patients with pheochromocytoma/paraganglioma 4.
- A study published in Blood pressure monitoring in 1998 found that amlodipine significantly reduced systolic and diastolic blood pressures during daytime, but had no significant effect on nighttime blood pressure 5.
Implications for Pre-Operative Management
- The available evidence suggests that amlodipine can be continued pre-operatively in some patients, but the decision should be made on a case-by-case basis, taking into account the patient's individual risk factors and medical condition 3, 4.
- It is essential to monitor the patient's blood pressure and adjust the amlodipine dose as needed to minimize the risk of hypotension during surgery 5, 2.
- Further studies are needed to fully understand the effects of amlodipine on intraoperative hemodynamics and to determine the optimal pre-operative management strategy for patients taking this medication.