Comparative Dose-Response of Intrathecal Dexmedetomidine for Post-Spinal Shivering

Al-Azhar University

Status and phase: Not yet enrolling; Phase 3

Conditions: Post-Spinal Shivering

Treatments: Drug: Group D10 (Higher-Dose Dexmedetomidine Group); Drug: Group P (Placebo Control Group); Drug: Group D2.5 (Low-Dose Dexmedetomidine Group); Drug: Group D5 (Moderate-Dose Dexmedetomidine Group)

Study type: Interventional

Funder types: Other

Identifiers

NCT07327879

RC. 2.12.2025

Details and patient eligibility

About

Dexmedetomidine, a highly selective α2-adrenergic agonist, when used intrathecally as an adjuvant to local anesthetics, prolongs sensory/motor block and may blunt thermoregulatory shivering mechanisms. Several randomized controlled trials and meta-analyses have demonstrated decreased shivering incidence with intrathecal dexmedetomidine, but reported doses vary (commonly 2.5, 5, and 10 µg, and in some trials up to 15-20 µg), and the balance between efficacy and adverse effects (sedation, bradycardia, and hypotension) is not fully established. Hence, a head-to-head randomized comparison of several low-to-moderate intrathecal doses is warranted.

Objective: to compare the safety and efficacy of three intrathecal dexmedetomidine doses (2.5 µg, 5 µg, 10 µg) versus placebo for the prevention of post-spinal shivering.

Enrollment: 120 estimated patients

Sex: All

Ages: 18 to 75 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Adult patients (age 18-75 years)
• Scheduled for ureteric stone removal surgery
• ASA(American Society of Anesthesiologists) physical status I, II, or III
• Able to provide informed consent

Exclusion criteria

• Known allergy to dexmedetomidine, bupivacaine, or other study medications
• Preexisting bradycardia (heart rate <50 beats per minute)
• Second- or third-degree atrioventricular (AV) block without a pacemaker
• Severe hepatic dysfunction
• Uncontrolled hypotension
• Pregnancy
• Chronic use of α₂-agonists or antagonists (e.g., clonidine, tizanidine)
• Infection at the planned spinal puncture site
• Coagulopathy or bleeding disorder
• Inability to rate or communicate shivering (e.g., language barrier, cognitive impairment)

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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120 participants in 4 patient groups, including a placebo group

Group P

Placebo Comparator group

Description:

Patients in this group will receive the standard spinal anesthetic consisting of hyperbaric bupivacaine 0.5% (15 mg) combined with an equivalent volume of normal saline (0.9% NaCl), containing no active dexmedetomidine. The total intrathecal injection volume will be standardized to 3.5 mL across all groups by adjusting the volume of saline added.

Treatment:

Drug: Group P (Placebo Control Group)

Group D2.5

Experimental group

Description:

Patients in this group will receive the standard spinal anesthetic (15 mg hyperbaric bupivacaine 0.5%) supplemented with a low dose of 2.5 µg of dexmedetomidine. Normal saline will be added to achieve the standardized total intrathecal volume of 3.5 mL.

Treatment:

Drug: Group D2.5 (Low-Dose Dexmedetomidine Group)

Group D5

Experimental group

Description:

Patients in this group will receive the standard spinal anesthetic combined with a moderate dose of 5 µg of dexmedetomidine. The total volume will be adjusted to 3.5 mL with normal saline.

Treatment:

Drug: Group D5 (Moderate-Dose Dexmedetomidine Group)

Group D10

Experimental group

Description:

Patients in this group will receive the standard spinal anesthetic supplemented with a higher dose of 10 µg of dexmedetomidine, with normal saline used to standardize the total volume to 3.5 mL.

Treatment:

Drug: Group D10 (Higher-Dose Dexmedetomidine Group)