RT Journal Article
SR Electronic
T1 Analgesic studies of codeine and oxycodone in patients with cancer. II. Comparisons of intramuscular oxycodone with intramuscular morphine and codeine.
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 101
OP 108
VO 207
IS 1
A1 W T Beaver
A1 S L Wallenstein
A1 A Rogers
A1 R W Houde
YR 1978
UL http://jpet.aspetjournals.org/content/207/1/101.abstract
AB The relative analgesic potency of single graded intramuscular doses of oxycodone and morphine was evaluated in a double-blind study in patients with chronic pain due to cancer. When both intensity and duration of analgesia are considered (total analgesic effect), oxycodone was 2/3 to 3/4 as potent as morphine, while in terms of peak analgesia, it was 8/10 to equipotent. In doses producing equivalent peak effect, oxycodone had a shorter duration of action than morphine. Intramuscular oxycodone was also compared to intramuscular codeine in a similar patient group. In terms of total analgesic effect, oxycodone was 10 times as potent as codeine, while in terms of peak analgesia it was 12 times as potent. These relative potency relationships of oxycodone, taken in conjunction with the oral/parenteral potency ratios of codeine and oxycodone established in the previous paper and several previous relative potency assays involving morphine, oxymorphone and codeine, demonstrate a highly consistent pattern of analgesic structure-activity relationships encompassing morphine, oxymorphone, codeine and oxycodone. The results of these studies do not appear to support the hypothesis that, in man, the analgesic activity of codeine is due to its O-demethylation to morphine.