Primary knee arthroplasty by total prosthesis is a painful surgery, performed on patients with advanced gonarthrosis (stage III), thus already presenting hyperalgesia and hyperalgesia and allodynia. This terrain makes the risk of postoperative hyperalgesia but also of persistent postoperative risk of persistent post-surgical pain. Nefopam is a non-opioid centrally acting analgesic drug used as a part of multimodal analgesia. The opioid-sparing effect of nefopam is still controversial across various surgical procedures. In France nefopam is only available as a parenteral formulation; however it is often administered orally. There is currently no study addressing the efficacy of oral nefopam for the postoperative pain management including pain prevention. The investigators conduct a prospective, double-blinded randomized controlled study with the main objective to examine the effect of perioperative orally administered nefopam on postoperative pain after a total knee arthroplasty. Secondary objectives include the quantification of wound allodynia, analysis of adverse events, clinical outcomes, and a pharmacokinetic study of orally given nefopam (plasma and cerebrospinal fluid dosage).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
40
Oral administration of nefopam 60mg 2 hours before the surgery following by 60mg each 8h for 24h. Oral nefopam is prepared ex-tempore from the intravenous formulation adding a taste masking compound by a non-caring nurse following detailed instructions.
Oral administration of a placebo 2 hours before the surgery following by one administration each 8h for 24h. Oral placebo is prepared ex-tempore with a taste masking compound by a non-charge nurse following detailed instructions
Département d'Anesthésie Réanimation, Groupement Hospitalier Nord, Hospices Civils de Lyon
Lyon, France
RECRUITINGTotal morphine consumption within 24h after the surgery.
Total dose of morphine consumed in 24h frame by a patient (PCA and/or additional morphine administration - parenteral or oral)
Time frame: 24 hours after the surgery.
Hyperalgesia - Pressure Pain Threshold
The pressure pain threshold is determined using a Von Frey monofilaments on both (operated and contralateral) knees 24 hours after incision.
Time frame: 24 hours after the surgery
Hyperalgesia - Punctate Pain Intensity
The Punctuate pain intensity is determined using a Von Frey monofilament n°5,88 (60 g/mm2) and a pain scale (0 = no pain, 10 = the worst pain), on both the operated knee and the contralateral knee 24 hours after incision.
Time frame: 24 hours after the surgery
Hyperalgesia - Allodynia zone
The extension of allodynia around the wound is measured using a calibrated brush (100 mNewton) 24 hours after incision.
Time frame: 24 hours after the surgery
Pain intensity
Self-reported pain intensity at rest and while moving the operated leg. Each item is scored on a scale ranging from 0 to 10 (0 = no pain, 10 = the worst pain)
Time frame: 24 hours after the surgery and 3 months after the surgery
Self reported safety outcomes
Nausea and vomiting, unusual sweating, drowsiness, hallucinations, nightmares, palpitations, irritability
Time frame: 24 hours after the surgery
Measures Safety outcomes
The incidence of acute urinary retention, and mean cardiac frequency (calculated from the recorded cardiac frequency 3 times a day) are recorded, confusion, acute angle glaucoma.
Time frame: 24 hours after the surgery
Pharmacokinetics:Plasmatic and cerebrospinal fluid concentration of nefopam
Plasmatic and cerebrospinal fluid concentration of nefopam is measured.
Time frame: 2 hours after the first oral administration of nefopam or Placebo.
Pharmacokinetics:Plasmatic and cerebrospinal fluid concentration of nefopam-beta-D-glucuronide
Plasmatic and cerebrospinal fluid concentration of nefopam-beta-D-glucuronide is measured.
Time frame: 2 hours after the first oral administration of nefopam or Placebo.
Pharmacokinetics:Plasmatic and cerebrospinal fluid concentration of nefopam-N-oxyde
Plasmatic and cerebrospinal fluid concentration of nefopam-N-oxyde is measured.
Time frame: 2 hours after the first oral administration of nefopam or Placebo.
Pharmacokinetics:Plasmatic and cerebrospinal fluid concentration of nefopam-N-demethyl
Plasmatic and cerebrospinal fluid concentration of nefopam-N-demethyl is measured.
Time frame: 2 hours after the first oral administration of nefopam or Placebo.
Pharmacokinetics:Plasmatic and cerebrospinal fluid concentration of Nefopam hydrochloride
Plasmatic and cerebrospinal fluid concentration of Nefopam hydrochloride is measured.
Time frame: 2 hours after the first oral administration of nefopam or Placebo.
Persistent postoperative pain - DN4 (or DN2 by phone)
The DN4 questionnaire (or DN2 questionnaire if the visit is realized by phone) ("Douleurs Neuropathiques 4/2" = Neuropathic pain 4/2 in french) is recorded to investigate persistent postoperative pain defined as pain on the operated knee 3 months after the surgery.
Time frame: 3 months after the surgery
Persistent postoperative pain - DN4
The DN2 questionnaire ("Douleurs Neuropathiques 2" = Neuropathic pain 2 in french, abbreviated DN4 questionnaire) is recorded by phone if the 3 months visit is realized out of time. If the score is positive (\>=3), the DN4 is recorded at hospital within 2 weeks post the 3 months visit.
Time frame: 4 months after the surgery
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