Droperidol is a neuroleptic drug (butyrophenone class) frequently used postoperatively as an antiemetic and a sedative.
General: anaphylactic shock.
Cutaneous: angioedema (swollen tongue), erythema of face and torso.
Intradermal skin-tests (1/1000) positive in 2 patients.
IgE-mediated hypersensitivity (positive cutaneous tests, one case with positive Prausnitz-Kustner test).
Increase in serum histamine due to inhibition of histamine-N-methyltransferase.