Dexmedetomidine prolongs spinal anaesthesia induced by levobupivacaine 0.5% in guinea-pigs

Abstract

Alpha-2 adrenoceptor agonists have been used in association with local anaesthetic to increase the duration of spinal anaesthesia. Intrathecal administration of clonidine prolonged motor blockade induced by local anaesthetic. Since the affinity of dexmedetomidine (DEX) to alpha-2 adrenoceptors is eight-times greater than clonidine, it is expected that DEX could be advantageous in clinical anaesthesia. We investigated the duration of motor nerve block induced by spinal injection of 0.5% levobupivacaine (LVB) associated with intrathecal or intraperitoneal administration of DEX. Seventy-two guinea-pigs were randomly divided in 12 groups, which were all treated with intrathecal injection of 50 microL of LVB. DEX was injected intrathecally with LVB in 6 groups or injected intraperitoneally after LVB in another 6 groups. Intrathecal DEX (0.1, 0.2 and 0.4 microg) increased the LVB-induced motor anaesthesia from 48 (41-66) min to 84.5 (52-91) min (P < 0.05), 101.5 (83-115) min (P < 0.05) and 105 (97-114) min (P < 0.05), respectively. Similarly, intraperitoneal DEX (20 and 40 microg kg(-1)) increased the motor blockade from 48.5 (33-59) min to 88 (71-114) min (P < 0.05) and 114.5 (103-156) min (P < 0.05), respectively. Pre-treatment with yohimbine reduced the duration of motor block from 101.5 (83-115) to 76.5 (68-86) min (P < 0.05) or from 114.5 (103-156) to 90 (83-93) min (P < 0.05) when DEX was administered by the intrathecal or intraperitoneal routes. Motor block induced by spinal injection of LVB was prolonged by intrathecal and systemic administration of DEX, which was partially dependent on activation of alpha-2 adrenoceptors.

Effects of Intrathecal Dexmedetomidine on Low-Dose Bupivacaine Spinal Anesthesia in Elderly Patients Undergoing Transurethral Prostatectomy

“…As seen in animal and human studies, dexmedetomidine prolongs not only the duration of sensory block, but also the degree and duration of the motor block. [11][12][13][14][15][16][17][18][19] The potentiation mechanism of motor block by dexmedetomidine is not well understood, but is suggested to be an additive or synergistic effect to the local anesthetics, 11,40) or related to the interference with neuromuscular activity, 11,41) or binding of α2-agonists to motor neurons in the dorsal horn. 11,33) In the current study, the numbers of patients that required postoperative analgesics were not different between two groups.…”

“…Intrathecally-administered dexmedetomidine has been shown to exert potent antinociceptive effects in animals. [9][10][11] To date, a few studies have reported on the effects of intrathecal dexmedetomidine combined with local anesthetics in humans. [12][13][14][15][16][17][18][19] In those studies, using 10-15 mg of bupivacaine, dexmedetomidine (3-15 µg) prolonged the block duration of local anesthetics with a low-rate of side effects.…”

Intravenous dexmedetomidine, but not midazolam, prolongs bupivacaine spinal anesthesia

“…Coşkuner et al 7 have shown that intravenous administration of dexmedetomidine might prolong the recovery time of the sensory blockade of bupivacaine-induced sensorial blockade during epidural anesthesia. Calasans-Maia et al 9 suggested that the duration of motor block induced by spinal injection of levobupivacaine could be prolonged by intrathecal or intraperitoneal administration of dexmedetomidine in guinea pigs. However, there are no clinical data regarding the association of intravenous dexmedetomidine and intrathecal local anesthetic.…”

“…[1][2][3] Also, it has been used safely as premedication or as a sedative agent in patients undergoing surgical procedures under regional anesthesia. 4,5 Although a synergistic interaction between intrathecal dexmedetomidine and local anesthetics has been observed in previous studies, [6][7][8][9] there are no clinical data regarding the effect of intravenous dexmedetomidine premedication on the duration of sensory and motor block during spinal anesthesia.…”

Effects of intracisternal dexmedetomidine on cerebral neuronal cells in rat: a preliminary study

“…It has been demonstrated that dexmedetomidine produces antinociception in systemic (23,28), intrathecal (2,29) or epidural administration (1). It has been reported that the addition of dexmedetomidine to local anesthetic solution in intravenous regional anesthesia improved the quality of anesthesia and decreased the analgesic requirements (5,20).…”