Oral clonidine reduces the requirement of prostaglandin E1 for induced hypotension

Can J Anaesth. 1999 Nov;46(11):1043-7. doi: 10.1007/BF03013199.


Purpose: To determine the effects of preanesthetic oral clonidine on the dose of prostaglandin EI (PGEI) required to produce hypotension during anesthesia.

Method: Oral placebo, 75 microg or 150 microg clonidine were administered 60 min prior to induction of anesthesia. Anesthesia was maintained with O2:N2O (30:70) and isoflurane 1.0%. After hemodynamic stabilization, an infusion of prostaglandin EI was started (0.05 microg x kg(-1) x min(-1)) and the rate of infusion was adjusted to maintain mean arterial pressure (MAP) between 60-70 mm Hg during operation.

Results: Duration of hypotension in placebo, 75 microg and 150 microg preanesthetic oral clonidine treated groups were 132+/-46, 117+/-37 and 129+/-56 min, respectively. The PGEI requirement in each group were 1563+/-180 (28.6+/-3.2), 594+/-197 (10.8+/-3.6) and 283+/-30 (5.5+/-3.6) microg (microg x kg(-1)), respectively. In addition, blood loss in each group were 1461+/-389, 805+/-240 and 931+/-40 ml, respectively.

Conclusion: Preanesthetic oral clonidine decreased the dose of PGEI required to produce hypotension, and decreased the blood loss during operation.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Administration, Oral
  • Adrenergic alpha-Agonists / pharmacology*
  • Adult
  • Aged
  • Alprostadil / pharmacology*
  • Blood Pressure / drug effects
  • Clonidine / pharmacology*
  • Female
  • Heart Rate / drug effects
  • Humans
  • Hypotension, Controlled*
  • Middle Aged


  • Adrenergic alpha-Agonists
  • Alprostadil
  • Clonidine