Optimal Intrathecal Morphine Dose for Better Post Cesarean Section Analgesia (Analgesia)

Comparison of Postoperative Analgesia With Different Doses of Intrathecal Morphine With Hyperbaric Bupivacaine and Fentanyl in Cesarean Section Patients: A Randomized Controlled Trial

Central neuraxial blocks (CNBs) remain the preferred anesthetic technique for cesarean section, with single shot spinal anesthesia (SSSA) being the standard practice at investigator's institute unless contraindicated. SSSA offers reliable intraoperative anesthesia and provides a few hours of postoperative analgesia. Enhanced recovery after cesarean section protocol has recommended the addition of intrathecal (IT) morphine to improve the postoperative quality of the recovery profile. Fentanyl improves the quality of intraoperative analgesia, while morphine significantly prolongs the postoperative pain relief, often lasting up to 24 hours.

Routine uterine exteriorization, practiced in all cases at investigator's institute, often results in peritoneal stretching pain during surgery. This visceral pain is managed with 10 mcg intrathecal fentanyl added to hyperbaric bupivacaine. For postoperative pain management, the intrathecal morphine is recommended by many guidelines and studies. Intrathecal morphine dose typically ranges from 50 to 300 mcg. The dose of morphine exceeding 150 mcg are usually associated with prolongation of analgesia with higher incidence of side effects like nausea, vomiting and pruritus. In selected cases, investigator had administered morphine 100-150 mcg and the clinical experience has shown reduced postoperative analgesic requirements and favorable recovery profile, with minimal adverse effects.

Despite these promising experiences and extensive literature on IT morphine, their is still lack formal data on the efficacy and safety profile of IT morphine in cesarean section patient. This comparative study will help institute to find the optimum dose of IT morphine with better postoperative analgesia quality with low side effects profile. The finding could serve as a foundation to promote routine use of intrathecal morphine in cesarean section anesthesia at investigator's institute.

Study Overview

• Status: Not yet recruiting
• Conditions: Post Cesarean Section Pain
• Intervention / Treatment: Drug: 0.5% bupivacaine heavy with fentanyl; Drug: 0.5% bupivacaine heavy with fentanyl plus morphine 50 mcg; Drug: 0.5% bupivacaine heavy with fentanyl plus morphine100 mcg; Drug: 0.5% bupivacaine heavy with fentanyl plus morphine 150mcg

• Study Type: Interventional
• Enrollment (Estimated): 180
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Bashu Dev Parajuli, MD Anaesthesiology; Phone Number: 00977+ 9851179038; Email: bashuparajuli2012@gmail.com
• Study Contact Backup: Name: Pooja Poudyal, MD Obstetric and Gynaecology; Phone Number: 00977+9841526853; Email: paudyalpooja@yahoo.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Pregnant lady > 36 weeks of gestation presenting for cesarean section under spinal anesthesia
• ASA II/ III
• Maternal Height > 150 cm
• BMI< 40 Kg/m2
• Elective Indication

Exclusion Criteria:

• Patient unwilling to take part in the study
• Patient with known allergy to the study medications
• Contraindication to Spinal Anesthesia

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Group BF; Intrathecal drug used: 0.5% hyperbaric bupivacaine 10mg(2ml) with fentanyl 10mcg(0.2ml), total volume of 2.2ml, single administration, no repetition of intervention In this group, no dose of morphine will be added.	Drug: 0.5% bupivacaine heavy with fentanyl; Spinal anesthesia with 0.5% bupivacaine heavy with fentanyl at L3-L4 intervertebral space using Quincke's spinal needle in sitting position in patients undergoing cesarean section to study the dose with better analgesia profile and lower side effect profile.
Experimental: Group BF-M50; Intrathecal drug used : 0.5% hyperbaric bupivacaine 10mg(2ml) with fentanyl 10mcg(0.2ml) plus morphine 50mcg (0.05ml) with total volume of 2.25ml single administration, no repetition of intervention	Drug: 0.5% bupivacaine heavy with fentanyl plus morphine 50 mcg; Spinal anesthesia with 0.5% bupivacaine heavy with fentanyl with morphine 50mcg at L3-L4 intervertebral space using Quincke's spinal needle in sitting position in patients undergoing cesarean section to study the dose with better analgesia profile and lower side effect profile.
Experimental: Group BF-M100; Intrathecal drug used : 0.5% hyperbaric bupivacaine 10mg(2ml) with fentanyl 10mcg(0.2ml) plus morphine 100mcg (0.1ml) with total volume of 2.3ml single administration, no repetition of intervention	Drug: 0.5% bupivacaine heavy with fentanyl plus morphine100 mcg; Spinal anesthesia with 0.5% bupivacaine heavy with fentanyl with morphine 100mcg at L3-L4 intervertebral space using Quincke's spinal needle in sitting position in patients undergoing cesarean section to study the dose with better analgesia profile and lower side effect profile.
Experimental: Group BF-M150; Intrathecal drug used : 0.5% hyperbaric bupivacaine 10mg(2ml) with fentanyl 10mcg(0.2ml) plus morphine 150mcg (0.15ml) with total volume of 2.35ml single administration, no repetition of intervention	Drug: 0.5% bupivacaine heavy with fentanyl plus morphine 150mcg; Spinal anesthesia with 0.5% bupivacaine heavy with fentanyl with morphine 150mcg at L3-L4 intervertebral space using Quincke's spinal needle in sitting position in patients undergoing cesarean section to study the dose with better analgesia profile and lower side effect profile.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To compare the incidence of postoperative pain after cesarean section with different doses of intrathecal morphine with bupivacaine among the four groups.	The parturient among study groups receiving different dose of intrathecal morphine with bupivacaine were compared for incidence of postoperative cesarean section pain. The pain is assessed by using Numerical Pain Rating Scale(NRS) ,a 11-point, standardized tool (0-10) in which 0 means "no pain" and 10 means "the worst pain imaginable". The number of parturient with NRS more than 3 will be compared for postoperative pain among the 4 groups.	NRS score is measured in recovery room for postoperative pain assessment. This time will be recorded as "time zero". Then in postoperative ward, NRS score is measured at 2 hours, 4 hours, 6 hours, 12 hours and 24 hours from 'time zero".

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To compare the first rescue analgesia demand time among the four groups	Rescue analgesia demand is defined as the first time after the cesarean section when the NRS score > 3, and analgesic will be needed. The time period after cesarean section when first rescue analgesic is needed will be compared among the four group. Inj.Ketorolac 30 mg iv will be supplemented first as rescue analgesic and recorded.	Postoperative period after cesarean delivery till 24 hour
To compare the total analgesic consumption in first 24 hours among the parturient of four group	Total analgesia consumption is defined as the total amount of paracetamol, ketorolac and tramadol received in the first 24 hours. From the time of first dose of ketorolac, regular analgesia will be prescribed as inj. ketorolac 30mg iv 8 hourly and inj. paracetamol 1gm iv 6 hourly for 24 hour. If the NRS score >3 at any point of time apart from the regular above medication, then Inj. tramadol 50 mg iv SOS will be provided and recorded. The number pf parturient with total analgesics consumption in 24 hour will be compared among the four groups.	Postoperative total analgesia consumption for first 24 hour
To compare the frequency of rescue analgesia demanded by parturient in first 24 hours among the groups	Frequency of rescue analgesia demand is measured by number of time patient with NRS >3 who demand for iv ketorolac, paracetamol and tramadol despite providing regular analgesia (inj ketorolac 30mg iv 8 hourly and inj.paracetamol 1gm iv 6 hourly) for 24 hour.	Postoperative period for first 24 hour
To compare the incidence of side effects like nausea, vomiting, respiratory depression, level of sedation and pruritus in first 24 hours among the groups	Number of parturient with treatment related side effects like nausea, vomiting, pruritus, respiratory depression and level of sedation are assessed and compared among the groups. Level of sedation is assessed by Pasero Opioid - Induced Sedation Scale (POSS) This score consist: of : S Sleepy, easy to arouse; Awake and alert; Slightly drowsy, easily arousable; Frequently drowsy, arousable, drift off to sleep during conversation; Somnolent, minimal or no response to verbal or physical stimulation A POSS score of S, 1, or 2 indicates an acceptable level of sedation, whereas a score of 3 or 4 indicates over-sedation.	Postoperative period for first 24 hour

Collaborators and Investigators

• Sponsor: Tribhuvan University Teaching Hospital, Institute Of Medicine.

Publications and helpful links

General Publications

• Sultan P, Halpern SH, Pushpanathan E, Patel S, Carvalho B. The Effect of Intrathecal Morphine Dose on Outcomes After Elective Cesarean Delivery: A Meta-Analysis. Anesth Analg. 2016 Jul;123(1):154-64. doi: 10.1213/ANE.0000000000001255.
• Choudhury M. Neuraxial anaesthesia in parturient with cardiac disease. Indian J Anaesth. 2018 Sep;62(9):682-690. doi: 10.4103/ija.IJA_474_18.

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): December 28, 2026
• Study Completion (Estimated): December 28, 2026

Study Registration Dates

• First Submitted: April 2, 2026
• First Submitted That Met QC Criteria: April 27, 2026
• First Posted (Actual): May 1, 2026

Study Record Updates

• Last Update Posted (Actual): May 1, 2026
• Last Update Submitted That Met QC Criteria: April 27, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Analgesia; Cesarean section; Postoperative pain; Intrathecal Morphine
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Nervous System Diseases; Postoperative Complications; Pathologic Processes; Neurobehavioral Manifestations; Perceptual Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative; Agnosia; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Heterocyclic Compounds, Fused-Ring; Alkaloids; Polycyclic Aromatic Hydrocarbons; Polycyclic Compounds; Piperidines; Heterocyclic Compounds, 4 or More Rings; Morphinans; Opiate Alkaloids; Heterocyclic Compounds, Bridged-Ring; Phenanthrenes; Morphine Derivatives; Morphine; Fentanyl
• Other Study ID Numbers: IRC/IOM/D-2026-339; NHRC 772-2025 (Other Identifier: NHRC)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual patient personal data will be kept confidential as our local IRC won't allow us to breach this policy.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No