IV Acetaminophen for Acute Post Operative Pain in C-Section Patients

Double Blinded Randomized Placebo Controlled Study in Evaluating the Effectiveness of IV Acetaminophen for Acute Post Operative Pain in C-Section Patients

Post-operative pain management after C-section is an important topic as the number of elective c-sections increases each year. Pain is managed either by giving opioids or by using non-opioids. The purpose of this study is to evaluate the effectiveness of IV Acetaminophen in pain relief and its impact in the usage of post-operative opioid requirements and opioid associated complications. The hypothesis is that four doses of IV Acetaminophen in conjunction with intrathecal or epidural morphine given to the patients after c-section will reduce post-operative opioid requirements and opioid associated complications.

Most of the opioids used are centrally acting drugs like morphine or its derivatives. The most common adverse reactions related to systemic administration of opioids are sedation, itching, constipation and less commonly, respiratory depression. One of the other management strategies for the pain control is the use of non-steroidal anti-inflammatory drugs (NSAIDS). Frequent use of NSAIDS is also associated with complications, such as gastric ulcer and platelet dysfunction. When compared to other non-NSAIDS, IV acetaminophen is a relatively safer drug with quicker onset of action. In an earlier conducted study, the onset of action of analgesia for a bolus dose of IV acetaminophen is 3 minutes. IV acetaminophen is FDA approved for management of mild to moderate pain. An adverse reaction associated with the prolonged usage of IV acetaminophen is hepatic injury. The most common adverse events encountered during previous clinical trials were nausea, vomiting, headache and insomnia.

IV form, total of 4 doses (each 1000 mg), each every 6th hourly to a maximum dose of 4000 mg in 24 hours.

every 6 hours for the first 24 hours after the c-section and there after every 8 hours until the patient is discharged or up to 48 hours

Sedation was assessed on a scale of 1-3 (1= wide awake, 2= sleepy but easily aroused, 3= sleepy and difficult to arouse). These assessments were made at the same time points as the pain assessments by the same research assistant. Score 1 is the only good outcome.

Subjects were specifically asked about adverse events such as nausea, vomiting, pruritus and breathing difficulties and information regarding their bowel movements. This information was collected on a scale of none, mild, moderate or severe. These are categorical outcomes.

every 6 hours for the first 24 hours after the c-section and there after every 8 hours until the patient is discharged or upto 72 hours. Finally, 1 week after discharge.

Data were not collected.The use of patient-controlled analgesia (PCA) pumps could have been utilized to standardize rescue medications. This would have allowed the collection of the proportion of subjects that required additional rescue medications. This was another possible endpoint that could have been evaluated.

every 6 hours for the first 24 hours after the c-section and there after every 8 hours until the patient is discharged or upto 72 hours.

Compare the percentage of patients using non-opioid pain medication at 24 hours, and 48 hours and had experienced any adverse events.

Inclusion Criteria: Elective full term CS patients Age 18 and above ASA I-III Exclusion Criteria: Allergic reaction to IV acetaminophen Not able to understand and sign the research consent Pregnancy induced hypertension or pre-eclampsia patients Planned intensive care admission patients Patients with severe hepatic impairment or active liver diseases (Two fold increase in any of the liver enzymes) Patients with serum creatinine>2mg/dl For nursing mothers, any evidence of hepatic dysfunction of the new born

Bernstein J, Spitzer Y, Ohaegbulam K, Reddy S, Song J, Romanelli E, Nair S. The analgesic efficacy of IV acetaminophen for acute postoperative pain in C-section patients: a randomized, double-blind, placebo-controlled study. J Matern Fetal Neonatal Med. 2022 Mar;35(5):933-940. doi: 10.1080/14767058.2020.1735337. Epub 2020 Mar 10.