The drugs contain nitric oxide, which opens blood vessels and relaxes muscles. This can cause a patient's blood pressure to become dangerously low when combined with anesthesia and other drugs used during surgery, according to the American Association of Nurse Anesthetists (AANA).
The group advises men not to take Viagra or Cialis the day before surgery because the drugs take more than 24 hours to clear the body.
It's also important for men to inform the person administering their anesthesia about their use of erectile dysfunction drugs.
"Patients should never feel embarrassed about telling their anesthesia professional that they use these products," Juan Quintana, AANA president, said in a new release from the association.
"Anesthesia professionals need to know this information to prepare the anesthesia plan, and to keep patients safe. As with all sensitive information, we honor the patient-provider trust," Quintana added.
It's also important for patients to share information about any other prescription drugs or complementary and alternative medicines they are using, such as ginseng, ginger or other dietary supplements.
The American Academy of Family Physicians has more about erectile dysfunction.
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