To determine if administration of IV acetaminophen following routine scheduled cesarean section delivery would decrease the need for narcotic medications to control post-operative pain. This was an IRB approved, double-blind, placebo-controlled randomized trial, registered on clinicaltrials.gov (NCT02046382). Women scheduled to undergo routine cesarean section for singleton pregnancy at term were recruited for enrollment. Study patients were given all medications in a standardized manner receiving either acetaminophen 1000mg intravenous (IV) every 8 hours for 48 hours or saline (placebo) for a total of 6 doses. The pharmacy prepared IV acetaminophen and saline in identical administration bags labeled "study drug" to ensure blinding. The initial dose of "study drug" was given within 60 minutes of skin incision. Quantity of breakthrough and scheduled analgesic medications, self-reported pain on the Faces Pain Scale (0-10) before and after study drug administration, and demographics were extracted from the patients' charts. Power calculation determined that 45 patients per study arm were required to detect a 30% reduction in post-cesarean narcotic requirement with 80% power and a significance level of 0.05. 133 patients were consented for the study. 29 were excluded and 104 patients were included with 57 of them receiving IV acetaminophen and 47 receiving placebo. There were no differences in baseline demographic characteristics including patient age, body mass index, gravidity, parity, ethnicity, comorbidities, or number of prior cesarean sections. There were no differences in estimated blood loss and length of surgery between groups. The total amount of narcotic medications consumed by patients receiving IV acetaminophen were significantly reduced when compared to the placebo group (47mg versus 65mg of oxycodone, p-value= 0.034). The total amount of ibuprofen used between groups was not different. There was no difference in the pain scores between the two groups before and after dose administration. There were no significant differences for reported medication side effects (nausea/emesis, respiratory depression, constipation) in either study arm. IV acetaminophen in the post-operative time period for cesarean section surgery resulted in a significant decrease in the need for narcotic medications required for pain control.

(Am J Obstet Gynecol. 2017;217(3):362.e1–362.e6) Postcesarean delivery pain management regimens are usually multimodal and include the use of regional anesthesia, nonsteroidal anti-inflammatory drugs, acetaminophen, and/or narcotic medications. Although intravenous (IV) acetaminophen has been shown to decrease narcotic consumption in the management of acute pain, there are limited studies on its use in the field of obstetrics for postcesarean delivery pain management. In the present study, the authors hypothesized that IV acetaminophen administration postcesarean delivery would reduce narcotic consumption 48 hours postoperatively.