[Analgesic activity of morphine suppository in rats].
Analgesic activity of morphine administered rectally as a suppository was investigated in rats in order to ascertain analgesic activity of morphine suppository. Morphine hydrochloride given rectally as a suppository produced analgesic activity in a dose-related manner in the tail pressure and acetic acid-induced writhing tests, and its potency (ED50 = about 17 and 0.689 mg/kg, respectively) was approximately twice that of morphine hydrochloride administered orally as an aqueous solution. The analgesic action was as durable as that of oral morphine, but its onset was faster. The plasma and brain levels of morphine reached peak until 30 min after rectal administration of morphine suppository, and these time-courses approximately corresponded with that of the analgesic action. These results suggest that morphine given rectally to rats as a suppository produces analgesic action equivalent or superior to orally administered morphine after absorption from the rectum.
Kita
A
A
Department of Pharmacology, Research Laboratories, Dainippon Pharmaceutical Co., Ltd., Osaka, Japan.
Nakamura
H
H
Kadokawa
T
T
Tan
T
T
D000700:Analgesics; D000818:Animals; D001921:Brain / Q000378:metabolism; D008297:Male; D009020:Morphine / Q000493:pharmacokinetics / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013488:Suppositories
D000700:Analgesics; D013488:Suppositories; D009020:Morphine