Propranolol hydrochloride, like other β-adrenergic blocking agents, is frequently used to treat hypertension, ischemic heart disease, some arrhythmias, and migraine headaches, as well as some common neurologic diseases. Epinephrine is used in combination with lidocaine as local anesthesia in dermatologic and cosmetic surgery. When patients receiving propranolol hydrochloride during surgery are exposed to epinephrine, they are at risk for a potentially lethal drug interaction.