Pain after ambulatory surgery remains an unsolved problem in The United States and Europe. It is associated with delayed hospital discharge and it can result to an increased opioid consumption with adverse side effects. The concept of multimodal analgesic technique was introduced more than 15 years ago and several techniques have been studied over the years including non steroidal antiinflammatory drugs (NSAIDs), acetaminophen, gabapentoids, ketamine, local and regional anesthetic techniques. Histamine can have effects on polymodal nociceptors and C-fibers, producing pain which is further increased by neurogenically mediated release of substance P from afferent pain fibers. Several non-selective or H1 -selective histamine receptors antagonists have been demonstrated in animal models and clinical pain. Chia et al demonstrated that preoperative promethazine had opioid sparing properties without adverse sedative effects in patients undergoing abdominal hysterectomy.