Related Experiment Video
Updated: Feb 24, 2026
Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
Sex differences in the daily rhythmicity of morphine consumption after major abdominal surgery
Objective:
The sex of the patients has been shown to affect postoperative pain and morphine consumption; still a clear understanding able to explain the reasons behind this difference struggles to emerge. Our research aimed to investigate one specific aspect of the variability in morphine consumption between sexes. Previous studies have shown that circadian rhythm can influence opioid consumption. Furthermore, circadian rhythm is different between female and male. Our analysis investigated the presence of differences in daily rhythmicity of morphine consumption between males and females.
Design:
This is a secondary analysis of data collected during 2 years long multicenter clinical trial (NCT01233752).
Settings:
Clinical data were collected in two Italian hospitals: IRCCS Foundation Policlinico S. Matteo (Pavia) and San Gerardo Hospital (Monza).
Patients:
The authors recorded data about morphine consumption in 157 patients who underwent major abdominal surgery, who received morphine intravenous patient-controlled analgesia (IV-PCA) as postoperative analgesia.
Interventions:
The authors analyzed the daily periodicity of effective boluses delivered by morphine IV-PCA with Poisson multilevel models, adjusted by the time of start for each pump. An effective bolus was defined as a correctly delivered bolus of 1 mg of morphine. The authors also evaluated the interactions among the time of the day and sex, age (2).
Main Outcome Measure(S):
Differences in sex of morphine consumption rhythms over the 24 hours of the day.
Results:
Morphine consumption showed a statistically significant daily periodicity (p < 0.001) in our study population. Consumption was higher around 2 AM (rate 0.4 mg/min·patient) and lower around 12 PM (rate 0.05 mg/min·patient). Global consumption was not associated with the pump start time, age, or sex. The daily periodicity of morphine consumption was different between males and females (p = 0.004), with males consuming more morphine during the night.
Conclusions:
Our analysis confirmed the presence of daily rhythm for morphine consumption in patients treated with IV-PCA morphine after major abdominal surgery. A difference in the daily periodicity was observed between sexes. No difference emerged in daily periodicity for the categories of age and BMI.
More Related Videos
04:11A Conditioned Place Preference Protocol for Measuring Incubation of Craving in Rats
Published on: November 6, 2018
09:54Combining Laser Capture Microdissection and Microfluidic qPCR to Analyze Transcriptional Profiles of Single Cells: A Systems Biology Approach to Opioid Dependence
Published on: March 8, 2020
Related Concept Videos
01:15Opioid Analgesics: Synthetic and Semisynthetic Opioids
01:20Opioid Analgesics: Morphine and Other Natural Cogeners
01:26Endoscopic Procedures IV: Sigmoidoscopy and Laproscopy
Sigmoidoscopy
Sigmoidoscopy is a diagnostic procedure that uses a flexible sigmoidoscope equipped with a light source and camera to examine the rectum and sigmoid colon. The procedure involves inserting the tube through the anus...
01:17Drugs Affecting GI Tract Motility: Opioids as Antidiarrheal Agents
Opioids, widely used antidiarrheal agents, mitigate diarrhea by slowing down...
01:25Analgesia and Pain Management
01:15Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...