In adult patients undergoing maxillofacial surgery, diphenhydramine (antihistamine) effectively reduces pain and emergence agitation, and improves recovery, concluded a randomized controlled trial published in European Archives of Oto-rhino-laryngology. Researchers aimed to explore the consequences of preemptive use of diphenhydramine on emergence agitation (a serious complication for the anesthesiologist and surgeon) and recovery post-maxillofacial surgery.

On the whole, 85 participants were divided into two groups: Group D or diphenhydramine group in which patients were administered diphenhydramine 0.5 mg/kg prior to anesthesia induction; Group C or Control group in which patients received normal saline (placebo). Before the incision, all patients received morphine sulfate 0.1 mg per kg gradually intravenously in 5 minutes.

During the anesthesia phase, constant infusion of remifentanil 0.2 μg/kg/h and inhalation of isoflurane was sustained. Paracetamol (also called acetaminophen) 1 g was infused 15 minutes prior to extubation. Emergence agitation during the extubation period following anesthesia, hemodynamics, and characteristics of recovery during the postoperative phase were all assessed.

During extubation time, the occurrence of emergence agitation was lower in Group D compared to Group C. Time from isoflurane withdrawal to extubation did not vary, as shown in Table 1:

Patients in group D had a lower grade of cough during emergence, pain severity, analgesic needs, and hemodynamic changes than Group C. Thus, preemptive use of diphenhydramine offered smooth emergence from anesthesia and improved quality of recovery following maxillofacial surgery.