During mandibular anesthetization with 4% solution of Ultracain-forte, a 13-year-old girl complained of sudden weakness, laboured respiration, nausea, fear. Objectively: the patient has pale skin covered with cold sweat, hyperemic spots on the face and neck. Respiration is frequent, the pulse is weak, blood pressure is 60/40 mm Hg, hands are cold. What is the most likely diagnosis?