Antinociceptive Effects and Spinal Cord Tissue Concentrations after Intrathecal Injection of Guanfacine or Clonidine into Rats

Post, Claes; Gordh, Torsten; Minor, Bruce G.; Archer, Trevor; Freedman, Jacob

doi:10.1213/00000539-198704000-00005

Cited by 47 publications

(25 citation statements)

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“…5,[33][34][35] Also, the potency of α2-adrenoreceptor agonist has been shown to correlate well with their binding affinity to spinal α2-adrenoreceptors. 36,37) Since Coombs et al first introduced the potent antinociceptive effects of intrathecal α2-adrenoreceptor agonists, clonidine (15-150 µg) has been frequently used in spinal anesthesia to improve the quality of local anesthetics. 7,8,38) But, side effect such as hypotension, bradycardia, and sedation is increased as dose of clonidine is increased.…”

Section: Discussionmentioning

confidence: 99%

“…39) Thus, we thought that 30 µg clonidine could be appropriate for intrathecal dose with 6 mg bupivacaine. Based on animal studies that dexmedetomidine showed a similar effect to clonidine with a 1 : 10 dose ratio in the spinal cord of animals, 20,36,37) Kanazi et al 17) also used 3 µg of intrathecal dexmedetomidine in their clinical study. Although the optimal dose of intrathecal dexmedetomidine has not been established, 3 µg of dexmedetomidine seems to be appropriate for potentiating the analgesic efficacy of low-dose spinal anesthesia referred from previous studies, 6,39) in which 15-45 µg of clonidine combined with low-dose ropivacaine (8 mg) or bupivacaine (6 mg) provided a prolonged spinal block.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

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

Kim

Lee

et al. 2013

Biological & Pharmaceutical Bulletin

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Low-dose bupivacaine can limit the spinal block level with minimal hemodynamic effects and yield a rapid recovery, but sometimes it may not provide adequate anesthesia for surgery. Dexmedetomidine, a selective α2-adrenoreceptor agonist, was shown to be a potent antinociceptive agent when given intrathecally in animals and humans. The purpose of this study was to evaluate the adjuvant effects of intrathecal dexmedetomidine in elderly patients undergoing transurethral prostate surgery with low-dose bupivacaine spinal anesthesia. Fifty-four patients undergoing transurethral prostate surgery were randomized into two groups receiving either dexmedetomidine 3 µg (n=27) or normal saline (n=27) intrathecally with 6 mg of 0.5% hyperbaric bupivacaine. The characteristics of the spinal block and postoperative analgesic effects were evaluated. The peak block level was similar for the two groups. However, the dexmedetomidine group demonstrated a faster onset time to the peak block and longer duration of spinal block than the saline group (p<0.01). The motor block scales at the time of peak sensory block and regression of 2-sensory dermatomes were higher in the dexmedetomidine group than in the saline group ( p<0.001). There was less analgesic request and the time to the first analgesic request was longer in the dexmedetomidine group than in the saline group (each 487, 345 min, p<0.05). Dexmedetomidine 3 µg when added to intrathecal bupivacaine 6 mg produced fast onset and a prolonged duration of sensory block and postoperative analgesia in elderly patients for transurethral surgery. However, recovery of motor block could be delayed in dexmedetomidine-added patients.Key words anaesthesia; spinal; dexmedetomidine; transurethral resection of prostate; bupivacaine; elderly patient Spinal block is a common anesthetic technique for patients undergoing transurethral resection of prostate (TURP). Most patients indicated for TURP are elderly and frequently associated with cardiopulmonary, endocrine, or other comorbidities.1) Thus, it is important to limit the block level to minimize hemodynamic changes during the spinal anesthesia in such patients.2,3) Low-dose local anesthetics can limit the block level and induce rapid recovery from anesthesia, but sometimes these low-dose local anesthetics may not provide an adequate anesthetic level for surgery. Intrathecal opioids or clonidine are frequently co-administered with local anesthetics to improve the anesthetic quality and postoperative analgesia [2][3][4][5][6][7][8] ; the synergistic action of clonidine with local anesthetics is well-established.6-8) Unlike opioids, intrathecal clonidine does not produce respiratory depression or pruritus, but usual dose of clonidine (15-150 µg) may be associated with bradycardia, hypotension, or sedation. 6-8)Dexmedetomidine is an S-enantiomer of medetomidine with a higher specificity for α2-adrenoreceptor (α2 : α1, 1620 : 1) compared to clonidine (α2 : α1, 220 : 1). It was first introduced into practical use as intravenous sedative after the appro...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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

Kim

Lee

et al. 2013

Biological & Pharmaceutical Bulletin

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“…DXM when used intravenously during anesthesia reduces opioid and inhalational anesthetics requirements [21,22] . Compared with clonidine a 2-adrenoreceptor agonist, the affinity of DXM to 2 receptors has been reported to be 10 times more than clonidine [23] , moreover, Kalso et al [5] and Post et al [24] reported a 1:10 dose ratio between intrathecal DXM and clonidine in animals. Clinical studies in surgical patients showed that intrathecal clonidine increases the duration of sensory and motor spinal block when added to spinal local anesthetics and this effect of clonidine is dose-dependent [25][26][27] , and doses of more than 75 µg intrathecal clonidine is accompanied by excessive sedation, hypotension and bradycardia.…”

Section: Discussionmentioning

confidence: 99%

Effect of Adding Dexmedetomidine versus Fentanyl to Intrathecal Bupivacaine on Spinal Block Characteristics in Gynecological Procedures: A Double Blind Controlled Study

Al-Ghanem¹

2009

American Journal of Applied Sciences

121

122

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Problem statement:The purpose of this study was to evaluate the onset and duration of sensory and motor block as well as operative analgesia and adverse effects of Dex Metedo Midine (DXM) or fentanyl given intrathecally with plain 0.5% bupivacaine for spinal anesthesia. Approach: seventy six patients classified as American Society of Anesthesiologists (ASA) status I, II and III scheduled for vaginal hysterectomy, vaginal wall repair and tension free vaginal tape were prospectively studied. Patients were randomly allocated to receive intrathecally either 10 mg isobaric bupivacaine plus 5 µg dexmetedomidine (group D n = 38) or 10 mg isobaric bupivacaine plus 25 mg fentanyl (group F n = 38), the onset time to reach peak sensory and motor level, the regression time for sensory and motor block, hemodynamic changes, and side effects were recorded. Results: Patients in group D had significant longer sensory and motor block times than patients in group F. the mean time of sensory regression to S1 was 274±73 min in group D and 179±47 min in group F (P < 0.001). The regression time of motor block to reach modified Bromage 0 was 240±60 min in group D and 155±46 min in group F (P< 0.001). The onset times to reach T10 dermatome and to reach peak sensory level as well as onset time to reach modified Bromage 3 motor block were not significantly different between the two groups. Conclusion: In women undergoing vaginal reconstructive surgery under spinal analgesia, 10 mg plain bupivacaine supplemented with 5 µg dexmetedomidine produces prolonged motor and sensory block compared with 25 µg fentanyl.

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“…Although there is the possibility of cephalad spread this has not been clearly demonstrated [152]. A central mechanism for the analgesic action of alpha-2 adrenoceptor agonists has been debated although there is evidence to suggest that there is no supraspinal mechanism.…”

Section: Analgesiamentioning

confidence: 99%

Alpha‐2 and imidazoline receptor agonistsTheir pharmacology and therapeutic role

Khan¹,

Ferguson²,

Jones³

1999

Anaesthesia

598

423

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SummaryClonidine has proved to be a clinically useful adjunct in clinical anaesthetic practice as well as in chronic pain therapy because it has both anaesthetic and analgesic-sparing activity. The more selective alpha-2 adrenoceptor agonists, dexmedetomidine and mivazerol, may also have a role in providing haemodynamic stability in patients who are at risk of peri-operative ischaemia. The side-effects of hypotension and bradycardia have limited the routine use of alpha-2 adrenoceptor agonists. Investigations into the molecular pharmacology of alpha-2 adrenoceptors have elucidated their role in the control of wakefulness, blood pressure and antinociception. We discuss the pharmacology of alpha-2 adrenoceptors and their therapeutic role in this review.

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Antinociceptive Effects and Spinal Cord Tissue Concentrations after Intrathecal Injection of Guanfacine or Clonidine into Rats

Cited by 47 publications

References 0 publications

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

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

Effect of Adding Dexmedetomidine versus Fentanyl to Intrathecal Bupivacaine on Spinal Block Characteristics in Gynecological Procedures: A Double Blind Controlled Study

Alpha‐2 and imidazoline receptor agonistsTheir pharmacology and therapeutic role

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