A COMPARATIVE STUDY OF THE ACTIONS OF MORPHINE AND DILAUDID (DIHYDROMORPHINONE HYDROCHLORIDE) ON THE INTACT SMALL INTESTINE OF THE DOG

¹ Department of Pharmacology, Jefferson Medical College, Philadelphia, Pennsylvania

1. The minimal effective intravenous dose of dilaudid hydrochloride on the jejunal Thiry-Vella loop of the dog is about 0.0002 mgm. per kilogram, that of morphine sulphate 0.002 mgm. per kilogram. For the ileum 0.0003 mgm. per kilogram was needed of dilaudid hydrochloride and 0.003 mgm. of morphine sulphate per kilogram body weight.

2. In small and medium doses dilaudid hydrochloride is ten times as active as is morphine sulphate.

3. Large doses of dilaudid hydrochloride have less effect than medium doses upon the tonus of the ileum and may cause a decrease in general tonus of the jejunum.

4. The average rate of rhythmic contractions of the ileum in the unanesthetized dog is 10.8 contractions per minute and for the jejunum 13.3 contractions per minute.

5. Both morphine sulphate and dilaudid hydrochloride decrease the amplitude of the rhythmic contractions during the period of increased tonus and increase the height of the rhythmic contractions of the jejunum especially, during the return of the gut to normal tonus. Usually the high rhythmic contractions persist for some time after control tonus has been reached. Dilaudid is the more potent.

6. Dilaudid hydrochloride and morphine sulphate in some cases cause a disappearance of the peristaltic contractions of both ileum and jejunum but in other experiments they increase them.

7. The effects of these drugs upon the rate of the rhythmic contractions were so variable that no conclusions could be drawn.

8. The pressure within the balloon and the size of the balloon are important factors in the interpretation and confirmation of results.

9. The blood pressure changes, following the intravenous administration of dilaudid hydrochloride in the non-anesthetized dog, were not uniform.