There is limited information on pharmacokinetics among morbidly obese patients and even
less among patients who have undergone metabolic and bariatric surgery (MBS). However, it
is known that these patients have altered metabolism due to anatomic and physiologic
changes related to body habitus, that are further complicated post MBS. The quadruple aim
consists of population health, reduces costs, improved healthcare worker experience and
improved patient experience. To provide a comprehensive healthcare approach for this
patient population, improved pain management through the utilization of lower cost
formulations of acetaminophen can result in improved patient experience through enhanced
pain management, avoidance of unnecessary ED visits and/or hospital readmissions.
Healthcare worker experience may be improved through less provider and nurse burden from
under managed pain, and improved patient outcomes resulting in greater job satisfaction.
In 2021, the annual drug overdose death rate in New Jersey is 32.4 per 100,000.3 It is
essential that alternatives to opioid medications provide adequate pain control if we are
to address this public health crisis.
No previous research was identified that evaluates the effectiveness of tablet vs liquid
oral acetaminophen despite some evidence of alterations in absorption of tablets among
post RYGB or LSG patients. In a small study among severely obese adolescent females,
results demonstrated the participants required more than double the amount of IV
acetaminophen to achieve equal serum concentrations. Additionally, a small study
demonstrated that to achieve near-equivalent pain control post-operatively of colorectal
surgery, IV acetaminophen was more effective when administered. Additional studies have
demonstrated increased clearance of drugs metabolized by CYP1A2 and CYP2D6 pathways.
These pathways are specifically involved in acetaminophen metabolism. The main pathway
for acetaminophen metabolism is glucuronidation. Obesity has been associated with
increase glucuronide clearance, therefore leaving less acetaminophen available for
metabolism by CYP2E1. Furthermore, the anatomic and physiologic changes post-operatively,
including a decrease gastrointestinal surface area and length contribute to alternations
in drug bioavailability. This evidence leads to the hypothesis that higher dosing of oral
acetaminophen is required to achieve adequate pain control when compared to non-obese
patients. Based upon previous literature and current understanding of post-operative
anatomic and physiologic alterations, there is a lack of evidence to support the
preferred formulation of oral acetaminophen in this patient population.
Objective:
To evaluate the therapeutic effects on pain control of acetaminophen pills vs.
acetaminophen liquid on post-operative pain control in patients status post RYGB or LSG.
Hypotheses/Research Question(s):
H0: There will be no difference in pain control between the liquid and pill formulations
of acetaminophen among patients status post RYGB or LSG.
H1: The investigators hypothesize that based on post-operative changes, the liquid
formulation of acetaminophen will result in improved pain control among patients status
post RYGB or LSG.
Research Procedures:
Prior to initiation of the study, pharmacy, nursing, and medical leadership will be
informed of the stratification of acetaminophen formulations based upon surgery day.
Patients will be stratified to two arms of the study utilizing the National Cancer
Institute's Clinical Trial Randomization Tool. Trial parameters using the asymptotic
maximal randomization method, ratio of 1:1, and a participant count of 150 were inputted
to create a randomization file. Presently, all patients receive acetaminophen as part of
their multi-modal post-operative pain management. The clinical coordinator of the
bariatric program on this study will recruit patients during the pre-operative admission
process. Consent will occur at the bedside in same day surgery. The clinical coordinator
for the bariatric program who is a study team member will be responsible for obtaining
patient consent into the study. It is anticipated the consent discussion will be less
than 15 minutes per patient. There is no waiting period expected.
It is anticipated that equal number of patients in both arms of the study will be
obtained.
Data Points:
Variable will include length of stay (LOS), morphine equivalents, documented pain level,
heart rate after cleared from anesthesia, blood pressure after cleared from anesthesia,
ED visits within 7 days from discharge, hospital readmissions within 7 days, out of
bed/ambulation, time to PO acetaminophen. Demographic data including age, sex, race,
weight, height, BMI, co-morbidities.
Study Duration:
The enrollment period is anticipated to be three months. Total study duration, including
data analysis and manuscript writing are anticipated to take two years.
Endpoints:
Participants may be removed from the study if experiencing inadequate pain control or
experiencing elevated glucose levels to ensure pain control and glucose are medically
managed as required. Participants will be removed from the study if they experience any
allergic reactions to any formulation of acetaminophen to ensure patient safety.
Primary outcomes include pain control. Secondary outcomes include LOS and morphine
equivalents.