title: Hemodynamic responses induced by dopamine and dobutamine in anesthetized patients premedicated with clonidine.
abstract: To test the hypothesis that the pharmacological effects of dopamine (DOA) and dobutamine (DOB) are altered when there is inhibition of the release of norepinephrine from nerve endings, we examined the hemodynamic responses to DOA and DOB in anesthetized patients premedicated with oral clonidine. Seventy adult patients were assigned to one of two groups (oral premedication with clonidine 5 microg/kg or no premedication). After the induction of general anesthesia, heart rate and systemic blood pressure (BP) were measured for 10 min after each of five IV infusions (3 and 5 microg x kg(-1) x min(-1) of DOA; 0.5, 1, and 3 microg x kg(-1) x min(-1) of DOB) in a randomized, double-blind manner. In patients given clonidine, the mean BP increases induced by DOA 5 microg x kg(-1) x min(-1) were significantly attenuated (P < 0.01), whereas the mean BP increases induced by DOB-0.5, 1, or 3 microg x kg(-l) x min(-1) were significantly enhanced (P < 0.01 or 0.05). The heart rate responses to DOA and DOB did not differ between patients with or without clonidine. Premedication with clonidine alters the effects on BP to both DOA and DOB. When small doses of DOA or DOB are used in clonidine-premedicated patients, differences of pharmacological profiles need to be considered for perioperative management.
  
  
  CONCLUSIONS
  Our randomized, double-blind study suggests that premedication with clonidine may enhance the effect on blood pressure response to a small dose of dobutamine (direct-acting) and attenuate that to a small dose of dopamine (mixed direct-and indirect-acting) in patients anesthetized with fentanyl and nitrous oxide.
authors.affiliation: Department of Anesthesiology & Critical Care Medicine, Gifu University School of Medicine, Gifu City, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ohata
authors.forename: H
authors.initials: H
authors.lastname: Iida
authors.forename: Y
authors.initials: Y
authors.lastname: Watanabe
authors.forename: S
authors.initials: S
authors.lastname: Dohi
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000328:Adult; D000768:Anesthesia, General; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D001794:Blood Pressure / Q000187:drug effects*; D002316:Cardiotonic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D003000:Clonidine / Q000008:administration & dosage / Q000627:therapeutic use*; D004280:Dobutamine / Q000008:administration & dosage / Q000627:therapeutic use*; D004298:Dopamine / Q000008:administration & dosage / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D009609:Nitrous Oxide / Q000008:administration & dosage; D011292:Premedication; D011941:Receptors, Adrenergic / Q000187:drug effects
chemical_list: D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D002316:Cardiotonic Agents; D011941:Receptors, Adrenergic; D004280:Dobutamine; D009609:Nitrous Oxide; D003000:Clonidine; D005283:Fentanyl; D004298:Dopamine