A Dose Ranging Effect of Preoperative Diphenhydramine on Postoperative Quality of Recovery After Ambulatory Surgery
Condition: Surgery; Pain
Study type: Interventional

Summary: 
      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.

      Diphenhydramine is an anti-histamine drug who has been found to be effective in reducing
      postoperative nausea and vomiting after ambulatory surgery but its effects on postoperative
      pain and other important outcomes after ambulatory surgery such as time to meet discharge
      criteria have not being studied.

      The MQOR 40 is a validated instrument that was specifically design to evaluate patient
      recovery after anesthesia and surgery. This instrument can be particularly valid to examine
      interventions which affect different spheres of patient recovery as is the case of
      diphenhydramine. The objective of this study is to determine a dose response effect of
      preoperative diphenhydramine on postoperative quality of recovery after ambulatory surgery.
      The use of preoperative diphenhydramine can improve patient's quality of recovery, decrease
      postoperative pain, opioid consumption and opioid related side effects after ambulatory
      surgery.

      The research question: Does a preoperative dose of diphenhydramine improve postoperative
      quality of recovery after ambulatory surgery? The hypothesis of this study is that
      preoperative diphenhydramine will improve postoperative pain, Postoperative nausea and
      vomiting (PONV), sleep which will translate in a better overall quality of recovery.
    


Intervention name(s): .9 normal saline; 25 mg diphenhydramine IV; 50 mg diphenhydramine IV
Intervention type(s): Drug; Drug; Drug
Intervention description(s): .9 normal saline administered before surgery.; 25 mg diphenhydramine IV administered before surgery; 50 mg diphenhydramine administered IV before surgery
Intervention MeSH terms: Diphenhydramine; Promethazine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: pain; anesthesia; surgery; postoperative