Efficacy of Oral vs. Intravenous Acetaminophen
Condition: Postoperative Pain
MeSH terms: Pain, Postoperative
Study type: Interventional
Phase: Phase 4

Summary: 
      The comparative efficacy of intravenous (IV) to oral (PO-'per os') acetaminophen in the
      management of postoperative pain is understudied and largely unknown. In this observer
      blinded randomized clinical trial, investigators aim to determine the comparative efficacy of
      PO (preoperative) vs. IV (intraoperative) acetaminophen in a sinus surgery population.
    

Detailed description: 
      The comparative efficacy of intravenous (IV) to oral (PO-'per os') acetaminophen is
      understudied and largely unknown. Intravenous acetaminophen has been available since 2010
      (http://www.accessdata.fda.gov/drugsatfda_docs/label/2010/022450lbl.pdf) and has proven
      superiority over placebo in human clinical trials. It is clearly advantageous in patients who
      cannot take oral medications. Similarly, oral acetaminophen has proven efficacy in the
      management of postoperative pain.

      However, in patients who can receive either formulation the incremental cost of the IV
      formulation, both to the Health System and patient, is substantial. This incremental cost
      would be justifiable if there were clear efficacy or safety data to support the preferential
      use of IV over PO acetaminophen.

      However, there is no evidence of superior safety and there are only two studies to our
      knowledge investigating the question of comparative efficacy. Fenlon et al. randomized 130
      patients undergoing 3rd molar (i.e., wisdom tooth) removal to IV vs. PO acetaminophen and
      found that PO acetaminophen was non-inferior to IV acetaminophen. The primary endpoint was
      postoperative pain score 1h after surgery. No safety concerns were identified in either
      group. Pettersson et al. randomized cardiac surgery patients to IV or PO acetaminophen,
      starting immediately postoperatively through the following morning, and found a significant
      opioid sparing effect of IV acetaminophen but no difference in pain scores or nausea.

      IV acetaminophen avoids first-pass hepatic metabolism and therefore generates higher serum
      and cerebrospinal fluid (CSF)/brain levels than does PO acetaminophen
      (http://ofirmev.com/Pharmacokinetics/). Based on the pharmacokinetic data, one can
      hypothesize that IV acetaminophen would be superior to PO acetaminophen at time points where
      serum and/or cerebrospinal fluid drug levels are higher.
    

Intervention name(s): Oral Acetaminophen; Intravenous acetaminophen
Intervention type(s): Drug; Drug
Intervention description(s): 1000mg oral acetaminophen + 400mg oral celecoxib given within one hour of incision; 400mg oral celecoxib given within one hour of incision + 1000mg IV acetaminophen within one hour prior to anesthetic emergence.
Other intervention name(s): Tylenol; Tylenol
Intervention MeSH terms: Acetaminophen
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Acetaminophen; Postoperative pain; Sinus Surgery