Comparison of Pain Relief Duration With Dexmedetomidine Versus Fentanyl Added to Spinal Anesthesia in Patients Undergoing Lower Limb Orthopedic Surgery

Comparison of Effective Analgesia Duration in Dexmedetomidine Versus Fentanyl as Adjuvants to Hyperbaric Bupivacaine for Unilateral Spinal Anesthesia in Lower Limb Orthopedic Surgeries

Status

Completed

Phases

Phase 4

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT07770542

Enrollment

Registered

2026-08-18

Start date

2025-08-01

Completion date

2026-01-30

Last updated

2026-08-18

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Postoperative Pain

Keywords

Dexmedetomidine, Fentanyl, Hyperbaric Bupivacaine, Intrathecal Analgesia, Lower Limb Orthopedic Surgery, Spinal Anesthesia, Postoperative Pain, Unilateral Spinal Anesthesia

Brief summary

The goal of this randomized clinical trial is to compare how long effective pain relief lasts when dexmedetomidine or fentanyl is added to hyperbaric bupivacaine during spinal anesthesia for lower limb orthopedic surgery. The main question the study aims to answer is: Does adding dexmedetomidine to hyperbaric bupivacaine provide longer-lasting effective pain relief after surgery than adding fentanyl? The study will include 60 adults aged 18-65 years who are classified as ASA Grade I or II and are undergoing lower limb orthopedic surgery under spinal anesthesia. Participants will be randomly assigned to one of two groups. Participants in the dexmedetomidine group will receive dexmedetomidine with hyperbaric bupivacaine. Participants in the fentanyl group will receive fentanyl with hyperbaric bupivacaine. After surgery, participants will be monitored for pain using a visual analogue scale (VAS), ranging from 0 (no pain) to 10 (severe pain). Pain will be assessed hourly during the first 12 hours and subsequently according to the study protocol. If the VAS pain score is greater than 3, nalbuphine will be given as rescue pain medicine. The study will measure the time from administration of spinal anesthesia until the participant first requires rescue pain medicine. The total amount of nalbuphine required after surgery will also be recorded. The study hypothesis is that adding dexmedetomidine to hyperbaric bupivacaine will provide a longer duration of effective pain relief than adding fentanyl.

Interventions

DRUGDexmedetomidine & Bupivacaine.

0.5 µg dexmedetomidine (0.5 mL) added to 3 mL of 0.5% bupivacaine and administered intrathecally for spinal anesthesia during lower limb orthopedic surgery

DRUGfentanyl and bupivacaine

25 µg fentanyl (0.5 mL) added to 3 mL of 0.5% bupivacaine and administered intrathecally for spinal anesthesia during lower limb orthopedic surgery.

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

DOUBLE (Subject, Outcomes Assessor)

Eligibility

Sex/Gender

ALL

Age

18 Years to 65 Years

Healthy volunteers

Inclusion criteria

* ASA status I and II * Orthopedic leg operations under spinal anesthesia

Exclusion criteria

* Spinal deformity * Coagulopathy (INR \>1.5) * Allergic reaction to local anesthetic * Recent heart attack (≤3-months) * With neurological diseases * Pulmonary diseases * Major liver or kidney disorders and infection of skin at the block site

Design outcomes

Primary

Measure	Time frame	Description
Duration of Effective Analgesia	From administration of spinal anesthesia, till 24 hours after surgery	Time from administration of the intrathecal study medication to the first requirement for rescue analgesia, defined as a postoperative visual analogue scale (VAS) pain score \>3. Duration will be recorded in minutes.

Countries

Pakistan

Contacts

STUDY_CHAIRAushtar A Naqvi, FCPS

Allama Iqbal Teaching Hospital

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Aug 19, 2026