Treatment of Pruritus With Intramuscular Promethazine

• Promethazine (Drug), also known as Phenergan: 1cc 25mg/ml Promethazine (study medication)
• Placebo (Drug), also known as salt water: 1cc 0.9% Sodium Chloride (placebo)

Primary outcomes

• Does the Addition of Promethazine Reduce Itching After Spinal Morphine for Cesarean Delivery? [Within first 24 hours after cesarean section]: Pruritus (itching) will be quantified by the ItchyQuant Scale. The ItchyQuant scale is a 0 -10 scale with 0 denoting no itch and 10, the worst itch possible. Participants were asked at 3 different time points (1 hour, 4 hours and 24 hours) after surgery to rate their itching. In the results here we reported any itching (a score greater than zero on the ItchyQuant scale) at 24 hours after surgery in each group.

Secondary outcomes

• Does Promethazine Impact Level of Consciousness Compared to Placebo After Cesarean Delivery? [Within first 24 hours post cesarean section]: Level of consciousness will be quantified by the RASS Scale. The RASS scale is scored with +4 to -5 scale with +4=combative, 0=alert and calm and -5=unrousable. Participants were asked at 3 different time points (1 hour, 4 hours and 24 hours) after surgery to rate their level of consciousness. In the results here we reported any score not noted to be 0 (alert and calm) at 24 hours after surgery in each group.
• Does Promethazine Change Nausea and Vomiting After Cesarean Compared to Normal Saline? [Within first 24 hours post cesarean section]: We asked patients to rate their sensation of nausea and/or vomiting as none, mild, moderate or severe at 4 time points after cesarean (1 hour, 4 hours and 24 hours after cesarean). Here, we rate any report of nausea and/or vomiting as opposed to no nausea and/or vomiting at 24 hours after cesarean among the patients who had Promethazine and normal saline.

Sex: Female, ages: 18 Years to 99 Years, accepts healthy volunteers

Inclusion Criteria:

* Pregnant adult female patients of at least 18 years of age consenting to a cesarean birth
* Willing to consent to study.

Exclusion Criteria:

* Male patients
* Incarceration
* Inability to communicate with the investigators
* Allergies to any medications used in the study
* Possessing any contraindication to spinal anesthesia (lack of consent, elevated intracranial pressure, preexisting neurological disease, thrombocytopenia/coagulopathy, hypovolemia, infection at the site of the procedure)
* Patients with an already prolonged QTc (>500 ms)
* Any reason an investigator believes study participation would not be in the best interest of the potential subject.

Participant flow

Outcome results

• Does the Addition of Promethazine Reduce Itching After Spinal Morphine for Cesarean Delivery? (Primary), Count of participants, Participants: Promethazine 22; Placebo 17
• Does Promethazine Impact Level of Consciousness Compared to Placebo After Cesarean Delivery? (Secondary), Count of participants, Participants: Promethazine 32; Placebo 31
• Does Promethazine Change Nausea and Vomiting After Cesarean Compared to Normal Saline? (Secondary), Count of participants, Participants: Promethazine 31; Placebo 32

Adverse events

Time frame: 24 hours after study drug administration

Limitations and caveats: We failed to enroll the planned number of patients due to a variety of factors, including challenges in availability of the study drug coupled with slow enrollment. Over two-thirds of the patients who were screened and were able to be contacted prior to surgery declined to participate. This did not support continuing enrollment.

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• Study Protocol and Statistical Analysis Plan (PDF, 2025-04-22)

• Adam Wendling, MD, Principal investigator, University of Florida