Dexmeditomedine is an α-2 adreno receptor agonist, which is approved as an intravenous sedative and analgesic drug. It is a useful adjuvant in regional anesthesia. Kanazi et al, found that 5μg Dexmeditomedine and 50μg clonidine are equipotent intrathecally when added to Bupivacaine in patients undergoing major surgeries in the abdomen and lower extremities. Dexmeditomedine given intrathecally along with Bupivacaine produce significantly longer duration of sensory and motor block than Bupivacaine alone without serious side effects. It maintains patient arousability and respiratory function. Dexmeditomedine has a role in the field of critical care and it also facilitates easy weaning from mechanical ventilation.

Fentanyl is a potent, synthetic narcotic analgesic with a rapid onset and short duration of action. It is a strong agonist at the μ-opioid receptors. Historically it has been used to treat breakthrough pain and is commonly used in pre-procedures as a pain reliever as well as an anaesthetic in combination with a benzodiazepine. Fentanyl is approximately 100 times more potent than morphine, with 100 micrograms of fentanyl approximately equivalent to 10 mg of morphine and 75 mg of pethidine (meperidine) in analgesic activity.It has an LD₅₀ of 3.1 milligrams per kilogram in rats, and an LD₅₀ of 0.03 milligrams per kilogram in monkeys.

Gynaecological procedures including vaginal hysterectomy, recanalization, ovarian cystectomy  are often done under regional anesthesia. Surgery on the uterus and other genital organs performed under epidural or spinal block is often accompanied by visceral pain, nausea and vomiting. Fentanyl in various doses (10, 20, 30, 40 μg) when added to spinal Bupivacaine increase the duration of analgesia and reduce intraoperative nausea and vomiting. Dexmedetomidine is an α2- adrenoreceptor agonist that is approved as an intravenous sedative and coanalgesic drug. Its use is often associated a decrease in heart rate and blood pressure. Intrathecal and epidural characteristics of Dexmedetomidine were studied in animals. Most of the clinical studies about intrathecal α2 adrenoreceptor agonist are related to clonidine. There is little in the literature about the use of intrathecal Dexmedetomidine with local anaesthesia in humans. Kanazi et al.found that 3 μg Dexmedetomidine and 30 μg clonidine are equipotent intrathecally when added to bupivacaine in patients undergoing urology procedures. The same author found that Dexmedetomidine and Clonidine produced significant short onset of sensory and motor block as well as significantly longer duration of sensory and motor block than Bupivacaine alone without serious side effects. The aim of this study is to compare the effect of Dexmedetomidine 5μg versus fentanyl 25 μg on intraoperative analgesia and the duration of sensory motor block when added to 10 mg intrathecal plain bupvacaine.