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Diuretics and Coumadin before surgery



Do you allow your patients to take diuretics the morning of surgery? Is there literature to support either taking or not taking the diuretic? How long prior to surgery where you want a patients PT/INR to be normal do you have them stop coumadin?


 NetWellness  is a forum for questions submitted by patient, not clinicians. I suspect you are a clinician, so I would normally suggest that you to try to get your question answered in some other way. However, I believe a few general comments about this issue may have some value to the lay public so I will try to address it!

Diuretics ("water pills") are commonly used to treat high blood pressure but are also given to patients with heart failure, or to treat swelling of the legs (edema). They are very useful medications, but they cause at least two problems when taken on the day of a surgical procedure. Firstly the need to urinate after taking a diuretic may be an inconvenience for patients travelling in by car. Secondly, and perhaps more importantly, diuretics may cause a decrease in blood volume ("hypovolemia") which can be detrimental during and after surgery and anesthesia, especially if the surgical procedure is a major one. So, under most circumstances, we tell our patients not to take their diuretics on the day of surgery. There are always exceptions to any guideline like this and patients should consult with their internist, surgeon, or (ideally) their anesthesiology about which medicines to take or withold on the day of surgery.

The same advice applies to deciding when (or whether) to stop taking coumadin, a potent anticoagulant (blood thining) medication - check with your doctor(s). Our usual practice is to have patients stop taking their coumadin four or five days before the procedure, and checking the PT/INR (a measure of how thin the blood is) by drawing blood on admission to the hospital or surgery center.

For more information:

Go to the Anesthesia health topic, where you can:

Response by:

Gareth S Kantor, MD Gareth S Kantor, MD
Assistant Professor of Anesthesiology
School of Medicine
Case Western Reserve University