A Phase 4 interventional study of Intervention 1: Intrathecal Dexmedetomidine with Bupivacaine and Intervention 2: Intrathecal Fentanyl with Bupivacaine in Spinal Anesthesia, Postoperative Complications and Dexmedetomidine, sponsored by Tribhuvan University Teaching Hospital, Institute Of Medicine.. Not yet recruiting at 1 site in Nepal. Open to participants aged 18 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-08-12.
Sponsored by Tribhuvan University Teaching Hospital, Institute Of Medicine. · Phase 4, Interventional, and Prevention
This study aims to compare two medications, dexmedetomidine and fentanyl, when used alongside a commonly used spinal anesthetic called bupivacaine in patients undergoing lower limb surgery. The main focus of the study is to see which combination causes fewer problems with urination after surgery - a condition known as postoperative urinary retention (POUR). POUR can lead to discomfort, delayed recovery, and a need for catheterization. Dexmedetomidine is a newer drug that may help reduce this problem compared to fentanyl, which is more commonly used but may increase the risk of urinary retention. This trial will help determine which medication combination provides better pain relief while reducing urinary side effects. The study is being conducted as a randomized, double-blind trial at a hospital in Nepal and will include 190 adult patients.
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Spinal anaesthesia is a common and effective method used to manage pain during lower limb surgeries. It allows patients to remain awake and comfortable while providing excellent pain control. To make spinal anaesthesia last longer and provide better pain relief, certain medications called adjuvants are added to the main anaesthetic drug, bupivacaine. Two commonly used adjuvants are fentanyl, an opioid, and dexmedetomidine, a medication that works on the body's alpha-2 receptors to provide sedation and pain relief.
However, a known side effect of spinal anaesthesia especially when combined with certain adjuvants is postoperative urinary retention (POUR). This condition occurs when a patient is unable to urinate normally after surgery. POUR can be uncomfortable, may delay recovery, and often requires insertion of a urinary catheter, which can increase the risk of infection and hospital stay.
This clinical trial, called the D-FAB POUR Trial, is designed to find out which of these two adjuvants dexmedetomidine or fentanyl is more likely to cause or prevent POUR when used with bupivacaine in patients undergoing elective lower limb surgery.
The study will involve 190 adult patients. Each participant will receive spinal anaesthesia with bupivacaine and be randomly assigned to also receive either dexmedetomidine or fentanyl. Neither the patients nor the doctors will know which medication is given in a process known as double-blinding to ensure fairness and eliminate bias.
The researchers will monitor the ability of patients to urinate at the third and sixth hours after surgery, using ultrasound to measure bladder volume. If the patient is unable to pass urine and the bladder is overly full, temporary or longer-term catheterisation may be needed. These outcomes will help determine how each drug affects bladder function.
In addition to urinary outcomes, the study will also look at side effects like nausea, vomiting, itching, changes in blood pressure or heart rate, sedation level, and how much extra pain relief the patient needs after surgery.
The goal of this research is to help doctors choose the best adjuvant to use in spinal anaesthesia, one that provides effective pain control without increasing the risk of urinary problems. The findings may lead to improved safety, comfort, and recovery for patients undergoing lower limb operations.
1,332 studies on the registry are indexed under Postoperative Complications; 311 are open to participants now.
This study's planned enrollment of 190 is above the median of 114 across 766 interventional studies indexed under Postoperative Complications.
Browse Postoperative Complications studies →Tribhuvan University Teaching Hospital, Institute Of Medicine. is the lead sponsor of 41 studies on the registry; 4 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants in this arm will receive 15 mg (3 mL) of 0.5% hyperbaric bupivacaine combined with 10 mcg (0.5 mL) of dexmedetomidine intrathecally. The total injected volume will be 3.5 mL.
Drug: Intervention 1: Intrathecal Dexmedetomidine with Bupivacaine
Participants in this arm will receive 15 mg (3 mL) of 0.5% hyperbaric bupivacaine combined with 25 mcg (0.5 mL) of fentanyl intrathecally. The total injected volume will be 3.5 mL.
Drug: Intervention 2: Intrathecal Fentanyl with Bupivacaine
Drug pages: Dexmedetomidine · Bupivacaine
Intervention 1: Intrathecal Dexmedetomidine with Bupivacaine Detailed Description: This intervention consists of a single intrathecal injection of 10 micrograms of dexmedetomidine combined with 15 mg (3 mL) of 0.5% hyperbaric bupivacaine, administered during spinal anaesthesia for lower limb surgery. The total volume administered is 3.5 mL. Dexmedetomidine is an alpha-2 non-opioid adjuvant used as a spinal adjuvant for enhancing analgesia
Drug pages: Fentanyl · Bupivacaine
This intervention consists of a single intrathecal injection of 25 micrograms of fentanyl combined with 15 mg (3 mL) of 0.5% hyperbaric bupivacaine, administered during spinal anesthesia for lower limb surgery. The total volume administered is 3.5 mL. Fentanyl is a lipophilic opioid commonly used as a spinal adjuvant for enhancing analgesia. This arm is being compared with dexmedetomidine to evaluate differences in POUR incidence, analgesic effectiveness, and side effect profiles.
Incidence of Postoperative Urinary Retention (POUR) at the 3rd Postoperative Hour
The primary outcome is the number of participants who are unable to void urine at the 3rd postoperative hour with a urinary bladder (UB) volume of ≥600 mL, confirmed by bladder ultrasound. Participants meeting this criterion will be considered to have postoperative urinary retention and will undergo in-out catheterization.
Time frame: 3 hours after spinal anesthesia
Requirement of Urinary Catheterization at 6th Postoperative Hour
Number of participants unable to void urine by the 6th postoperative hour, requiring insertion of a Foley's catheter.
Time frame: 6 hours after spinal anesthesia
Plan to share: Yes — De-identified individual participant data (IPD) related to primary and secondary outcomes (including urinary retention, adverse events, and analgesic requirement) will be made available upon reasonable request from qualified researchers. Data will be shared after publication of the main study findings. Access will require a data use agreement and approval by the principal investigator and ethical committee.
Supporting information: Study protocol, Statistical analysis plan, Clinical study report
Time frame: 6 months after publication of the primary study results in a peer-reviewed journal.
Access criteria: Who will have access: Qualified researchers, academic collaborators, and clinicians involved in similar fields of study may request access to the de-identified individual participant data (IPD). What will be accessible: De-identified datasets related to primary and secondary outcomes - including incidence of postoperative urinary retention (POUR), hemodynamic data, sedation scores, rescue analgesic use, and adverse events. Supporting documents such as the study protocol, statistical analysis plan, and case report forms (CRFs) may also be shared upon request. How to access: Interested researchers must submit a formal written request to the principal investigator (Dr. Sujan Dhakal, szndkl44@gmail.com) explaining the purpose and scope of the intended data use. Requests will be reviewed by the study team and ethics oversight body. Upon approval, access will be granted through a secure data-sharing agreement, ensuring compliance with confidentiality and ethical standards.
No publications or documents are linked to this record.
Start is estimated for Sep 2025; primary completion for Sep 2026, 11 months later.
Of 45 non-industry phase 4 interventional studies under Postoperative Complications, half reached primary completion within 25 months of starting (the median), counting those still running; a quarter within 19 and three quarters within 32. This study's planned 11 months is below that.
Counting every sponsor, half of 46 studies reached it within 25 months; a quarter within 19 and three quarters within 32.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Jun 2025. You cannot join it, but the record below documents what was studied.
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Studies of the drugs tested here: Dexmedetomidine · Bupivacaine
Tribhuvan University Teaching Hospital, Institute Of Medicine.