Analgesic efficacy and bioavailability of ketorolac in postoperative pain: a probability analysis.
BACKGROUND
The analgesic efficacy and bioavailability of 30 mg intramuscular ketorolac was studied in 24 patients with severe or very severe postoperative pain.


METHODS
Pain and pain relief were determined by a five-point verbal rating scale and data were submitted to a probability analysis. Ketorolac plasma levels were determined by high-performance liquid chromatography.


RESULTS
Two patients chose not to finish the study; 22 patients completed the study achieving at least good pain relief. Of these 22 patients, 13 reached complete pain relief. Ketorolac was rapidly absorbed. Notwithstanding, pain relief increased gradually, showing considerable delay with regard to plasma concentrations. Analysis of the probability-time curves revealed that 25% of the patients obtained moderate pain relief at 7 min after ketorolac administration, 50% at 11 min, 75% at 29 min, and 95% at 60 min. Good pain relief was achieved in 25, 50, and 75% of the patients at 1.1, 1.8, and 2.7 h, respectively. Complete pain relief was achieved in 25% and 50% of the patients at 2.6 h and 3.7 h, respectively. The probability of exhibiting an acceptable pain relief in responsive patients for more than 5 h was 0.97. No serious side effects were detected.


CONCLUSIONS
Results show that 30 mg intramuscular ketorolac is an adequate treatment for postoperative pain in the Mexican population. Therefore, the use of higher doses is not justified. Due to gradual installation of analgesia, administration of additional analgesic medication before 1 h is not recommended.
Pérez-Urizar
J
J
Departamento de Farmacología y Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV del IPN), México, D.F., Mexico. ppurizar@mpsnet.com.mx
Granados-Soto
V
V
Castañeda-Hernández
G
G
Hong
E
E
González
C
C
Martínez
J L
JL
Flores-Murrieta
F J
FJ
D000328:Adult; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D020910:Ketorolac / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000097:blood / Q000188:drug therapy*; D016896:Treatment Outcome
D018712:Analgesics, Non-Narcotic; D000894:Anti-Inflammatory Agents, Non-Steroidal; D020910:Ketorolac