A minimum dose of clonidine added to mepivacaine prolongs the duration of anesthesia and analgesia after axillary brachial plexus block.
This study assessed the minimum dose of clonidine required to prolong the duration of both anesthesia and analgesia after axillary brachial plexus blockade. Eighty patients scheduled for elective hand surgery were divided into eight groups in a randomized, double-blind fashion. An axillary brachial plexus block was performed with 40 mL 1% mepivacaine plus 1:200,000 epinephrine. The control group received no clonidine. In the other groups, increasing doses of clonidine (0.1, 0.2, 0.3, 0.4, 0.5, 1, and 1.5 micrograms/kg) were added to the local anesthetic solution. Onset time, duration of anesthesia and analgesia, postoperative pain score, intake of analgesics, and adverse effects were recorded. The eight groups were comparable in terms of onset time, postoperative pain score, and analgesic requirement. The minimum dose of clonidine required to significantly prolong the duration of analgesia and anesthesia was, respectively, 0.1 and 0.5 microgram/kg. No side effects (sedation, drowsiness, bradycardia, arterial hypotension) were reported. We conclude that the dose of clonidine required to prolong significantly the duration of both anesthesia and analgesia after axillary brachial plexus blockade is 0.5 microgram/kg and that, at this dose, clonidine may be used without important reported side effects even in outpatients.
Department of Anesthesiology, Universisté Catholique de Louvain School of Medecine, St. Luc Hospital, Brussels, Belgium.
F J
FJ
Singelyn
J M
JM
Gouverneur
A
A
Robert
D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D000328:Adult; D000556:Ambulatory Surgical Procedures; D000698:Analgesia; D000700:Analgesics / Q000008:administration & dosage / Q000627:therapeutic use; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000009:adverse effects; D001365:Axilla; D001917:Brachial Plexus; D001919:Bradycardia / Q000139:chemically induced; D003000:Clonidine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D003243:Consciousness / Q000187:drug effects; D004311:Double-Blind Method; D017558:Elective Surgical Procedures; D005260:Female; D006225:Hand / Q000601:surgery; D006801:Humans; D007022:Hypotension / Q000139:chemically induced; D008297:Male; D008619:Mepivacaine / Q000008:administration & dosage* / Q000009:adverse effects; D008875:Middle Aged; D009407:Nerve Block; D010147:Pain Measurement; D010149:Postoperative Pain / Q000517:prevention & control; D012894:Sleep Stages / Q000187:drug effects; D013997:Time Factors
D000316:Adrenergic alpha-Agonists; D000700:Analgesics; D000779:Anesthetics, Local; D008619:Mepivacaine; D003000:Clonidine