Dexmedetomidine is a highly selective α₂-adrenergic receptor agonist that exerts its effects by inhibiting the release of norepinephrine at presynaptic nerve terminals, leading to reduced sympathetic activity; This mechanism results in analgesia, sedation, and anxiolysis without significant respiratory depression
Eligibility
Sex
ALL
Min age
18 Years
Max age
60 Years
Healthy volunteers
No
Inclusion Criteria:
* Age 18-60 years
* American Society of Anesthesiologists (ASA) Physical Status Classification System I or II
* Scheduled for elective knee surgery under spinal anesthesia
* Body mass index (BMI) 18-30 kg/m²
* Able to provide informed consent
Exclusion Criteria:
* Pregnant or lactating women
* Hypersensitivity to dexmedetomidine
* Chronic kidney diseases serum creatinine \>1.5 mg\\dl or Patient has known renal disease
* Chronic opioid or sedative use
* Any cardiac conduction abnormalities
* Uncontrolled arterial hypertension
* Neuropathy
* Diabetes mellitus
* Impaired perfusion of the operative limb (Edema, Peripheral vascular Disease e.g "Raynaud Phenomenon")
* History or recent lower limb deep venous thrombosis (DVT) or Phlebitis
* Infection or vascular access limitation in the operated lower limbs
* Any contraindication of spinal anesthesia e.g "Coagulopathy"
* Any contraindications for tourniquet e.g "sickle cell anemia"
Primary outcome measure(s)
postoperative duration of analgesia — within 24 hours after the surgery the time measured from the study drug injection to the first request of analgesia by the patient
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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