Possible interaction between sevoflurane and Aloe vera.

OBJECTIVE

To describe a patient with massive intraoperative bleeding after oral consumption of Aloe vera tablets.

METHODS

A 35-year-old woman lost 5 L of blood during surgery as a result of a possible herb-drug interaction between Aloe vera and sevoflurane.

CONCLUSIONS

Aloe vera is a common herb used for antiinflammatory and antiarthritic activity, as well as antibacterial, hypoglycemic, and lipid-lowering effects. Compounds contained within Aloe vera can cause a reduction in prostaglandin synthesis, which may inhibit secondary aggregation of platelets. Sevoflurane inhibits thromboxane A(2) formation by suppression of cyclooxygenase activity, impairs platelet aggregation, and prolongs bleeding. Although the vascularity and size of the hemangioma were the most important factors for the massive intraoperative blood loss, concomitant use of sevoflurane and Aloe vera played a contributory role. An objective causality assessment revealed that this adverse event was possible as a result of the sevoflurane and Aloe vera interaction.

CONCLUSIONS

There is a potential herb-drug interaction between Aloe vera and sevoflurane based on the antiplatelet effects of these 2 agents. Herbal medications with antiplatelet potential should be discontinued before anesthesia and surgery.