Duloxetine and Dexamethasone for Improving Postoperative Pain
Condition: Post Operative Pain Control
MeSH terms: Pain, Postoperative
Study type: Interventional
Phase: Phase 4

Summary: 
      75 female patients were randomly allocated into one of three equal groups. Group I(GI)
      received Dulox 60 mg orally and 100 ml 0.9% sodium chloride solution (NS) intravenous
      infusion (IVI) over 15 min, group II(GII): received combined Dulox capsule 60 mg orally and
      Dex 0.1mg/kg mixed with 100 ml NS IVI and group III(GIII) received identical placebo
      duloxetine capsule and 100 ml NS IVI as a placebo for Dex, 2 hours preoperatively. Patients'
      vitals, VAS and sedation score were assessed at 30 minutes, 1h, 2 h, 6h and 12h
      postoperatively. Total pethidine requirements, plasma cortisol, PONV and patient's
      satisfaction were recorded.
    

Detailed description: 
      This study was designed to be a randomized, placebo-controlled, double-blinded parallel study
      and this study was carried out at Ain-Shams university hospitals, from December 2014 to
      January2016, on 75 female patients aged between 25 and 35 years old of the American Society
      of Anesthesiologists (ASA) physical status I and II scheduled for elective laparoscopic
      gynecological surgeries (for infertility) under general anesthesia. Approval was obtained
      from the institutional ethical committee and written informed consent was obtained from all
      patients.

      Patients were not admitted to the study if any of the following criteria were present: (1)
      patient's refusal, (2) duration of surgery more than 90 minutes, (3) allergy to any drugs of
      the study, (4) smokers, history of drug or alcohol abuse, (5) treatment with antidepressants,
      (6) history of diabetes or epilepsy, (7) , history of chronic pain or daily intake of
      analgesics within 24 h before surgery, (8) treatment with systemic glucocorticoids within 4
      weeks before surgery and (9) impaired kidney or liver functions.

      Patients were randomly allocated into 3 equal groups, group (I) (GI) (n=25) each patient
      received Dulox capsule (60mg) orally with sips of water 2 hours preoperatively and 100 ml
      0.9% sodium chloride solution (NS) intravenous infusion (IVI) over 15 min (Placebo), group
      (II) (GII) (n=25) each patient received combined Dulox capsule (60 mg) orally with sips of
      water and Dex 0.1mg/kg diluted in 100 ml 0.9% NS IVI over 15 min, 2 hours preoperatively and
      group (III) (GIII) (control group) (n=25) each patient received a placebo capsule identical
      to Dulox capsule and 100 ml 0.9% NS IVI over 15 min, as a placebo for dexamethasone 2 hours
      preoperatively. Dulox was presented as CYMBALTA® capsules manufactured by Lilly del Caribe
      Inc. Imported by Elco and Dex was presented as dexamethasone sulphate ampoules 8mg in 2ml.
      (Medical Union Pharmaceutical, Egypt MUP). Randomization was done using computer-generated
      number table of random numbers in a 1:1 ratio and conducted using sequentially numbered,
      opaque and sealed envelope (SNOSE). Active Dulox capsules were indistinguishable from placebo
      capsules and placebo capsules contained starch. The study drugs were prepared by the hospital
      pharmacy and follow-up of patients was conducted by the anesthesia residents not involved in
      any other part of the study.

      During the preoperative anesthetic evaluation, patients were familiarized with 10 cm marked
      visual analogue scale (VAS) for PO assessment of pain, where 0 cm defines no pain and 10 cm
      defines the maximum intolerable pain. Patients were also assured that they would receive
      intramuscular injection (IM) of pethidine 0.5 mg / kg once they experienced pain
      postoperatively (patients with (VAS > 3).

      The general anesthesia technique was standardized for all the patients as well as monitors
      including 5 lead ECG, non- invasive blood pressure (NIBP) monitor, pulse oximetry and
      capnography after intubation using Datascope monitors. Neuromuscular function was monitored
      using a peripheral nerve stimulator. After establishing an intravenous (IV) line, induction
      of general anesthesia with fentanyl (2 ug/kg) and sleeping dose of propofol followed by
      rocuronium (0.6 mg/kg) to facilitate orotracheal intubation was done. Anesthesia was
      maintained using isoflurane in oxygen and air. Ranitidine (50 mg/ampoule) was given diluted
      in 10 ml 0.9% sodium chloride solution (NS) slowly (IV) over 10 minutes as a gastroprotective
      regimen. At the end of the surgery, the residual neuromuscular paralysis was antagonized with
      neostigmine (0.05 mg/kg) and atropine (0.01 mg/kg). After satisfactory recovery, patients
      were extubated and transferred to the post-anesthesia care unit (PACU) where they were
      monitored with ECG, NIBP and pulse oximetry.

      Assessment of patients' vitals (HR, MAP), arterial SpO2, sedation score, visual analog scale
      (VAS), the first analgesic requirement time and adverse effects (e.g. nausea, vomiting
      (PONV), pruritis) were done at 30 minutes, 1h, 2 h, 6h and 12h postoperatively.

      PO pain was evaluated at rest based on visual analogue scale, first time to ask for rescue
      analgesia and total pethidine requirements in 12 hours (mg) postoperatively were recorded.
      Assessment of sedation was according to sedation score (Ramsay sedation scale) (14).

      Hypotension was considered if there was 20% decrease below the baseline for MAP and was
      treated with IV bolus of ephedrine (3-6 mg). Bradycardia was considered if the heart rate <
      55 beats/min and was treated with IV atropine (0.01mg/kg). Respiratory depression was defined
      as a respiratory rate less than 10 breaths/min-1 or peripheral oxygen saturation less than
      95% and was treated with oxygen through a transparent face mask and the intermittent doses of
      IV naloxone (0.4 mg). IV granisetron (1mg) was given in case of vomiting or after 2
      successive episodes of nausea. Pruritus was evaluated with a 4-point scale (0=absent, 1=mild,
      2=moderate, 3=severe or requiring treatment), and patients with severe pruritus were treated
      with IV clemastine (TavegylR) (2 mg / ampoule).

      Patient's satisfaction was done by asking the patient to answer the question, 'How would you
      rate your experience after the surgery?' using a 7-point Likert verbal rating scale (15) and
      acceptable satisfaction score of the patient being 5-7.

      Hormonal stress response was assessed through recording plasma cortisol (micrograms / dl) 2
      hours postoperatively. Serum cortisol was measured by a Fluorescence Polarization Immunoassay
      Technology (FPIA) by the Abbott AXSYM system with the following reference ranges (morning
      serum cortisol 4.2-38.4 ug/dl) and evening serum cortisol 1.7-16.6 ug/dl).
    

Intervention name(s): Dulox capsule (60mg); combined Dulox capsule (60 mg) orally and Dex 0.1mg/kg diluted in 100 ml 0.9% NS IVI; a placebo capsule identical to Dulox capsule and 100 ml 0.9% NS IVI over 15 min, as a placebo for dexamethasone
Intervention type(s): Drug; Drug; Drug
Intervention description(s): each patient received Dulox capsule (60mg) orally with sips of water 2 hours preoperatively and 100 ml 0.9% sodium chloride solution (NS) intravenous infusion (IVI) over 15 min; each patient received combined Dulox capsule (60 mg) orally with sips of water and Dex 0.1mg/kg diluted in 100 ml 0.9% NS IVI over 15 min, 2 hours preoperatively; each patient received a placebo capsule identical to Dulox capsule and 100 ml 0.9% NS IVI over 15 min, as a placebo for dexamethasone 2 hours preoperatively.
Other intervention name(s): Dulox was presented as CYMBALTA® capsules manufactured by Lilly del Caribe Inc.; Dex was presented as dexamethasone sulphate ampoules 8mg in 2ml. (Medical Union Pharmaceutical, Egypt MUP)
Intervention MeSH terms: Dexamethasone; Dexamethasone acetate; BB 1101
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Prevention
Keywords: Duloxetine, Dexamethasone, Postoperative pain, side effects.