Investigation of the pharmacokinetics and analgesic effects of an intramuscular injection of sustained-release sufentanil for postoperative pain: an open study.
OBJECTIVE
To investigate the pharmacokinetics after an intramuscular (IM) injection of sufentanil in thin vegetable oil in postsurgical patients and to determine whether sustained-release IM sufentanil can provide safe and sufficient analgesia of long duration in these patients.


METHODS
Open study.


METHODS
University hospital.


METHODS
10 ASA physical status I and II patients aged 18 to 65 years who were scheduled for elective surgery.


METHODS
All patients were premedicated with lorazepam and anesthetized with a general anesthetic technique containing nitrous oxide, fentanyl, and isoflurane. As soon as significant pain [visual analog scale score of 5 or greater (range, 0 = no pain to 10 = worst pain imaginable)] occurred during the early postoperative period, the patient received an IM injection of sustained-release sufentanil.


RESULTS
During the first 48 hours following surgery, blood samples were taken for determination of plasma sufentanil concentrations. Blood pressure, heart rate, respiratory rate, pain scores, and sedation scores were documented at the same time. The IM administration of sufentanil in thin vegetable oil provided sufficient pain relief, although the onset of analgesia was rather slow (+/- 1 hour). The analgesic effect was still apparent 48 hours later. Plasma concentration of sufentanil at the different time points varied from 0.021 to 0.142 ng/ml, with a mean maximal peak concentration of 0.103 ng/ml. The plasma concentration 48 hours after injection varied from 0.026 to 0.074 ng/ml.


CONCLUSIONS
Although an IM injection of sufentanil in thin vegetable oil is effective for postoperative pain relief, it is associated with wide interindividual variability in plasma concentration of sufentanil and long duration of action.
Bergmans
G
G
Department of Anesthesiology, Katholieke Universiteit Leuven, Belgium.
Vanacker
B
B
Van Aken
H
H
Noorduin
H
H
Van Peer
A
A
Gryseels
J
J
Verhamme
B
B
D000293:Adolescent; D000328:Adult; D000368:Aged; D000768:Anesthesia, General; D001794:Blood Pressure / Q000187:drug effects; D003692:Delayed-Action Preparations; D017558:Elective Surgical Procedures; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007273:Injections, Intramuscular; D008140:Lorazepam / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000188:drug therapy*; D014677:Pharmaceutical Vehicles; D010938:Plant Oils; D011229:Preanesthetic Medication; D012119:Respiration / Q000187:drug effects; D017409:Sufentanil / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology*; D013997:Time Factors
D003692:Delayed-Action Preparations; D014677:Pharmaceutical Vehicles; D010938:Plant Oils; D017409:Sufentanil; D008140:Lorazepam