STUDIES ON THE PHARMACOLOGICAL ACTION OF CORIAMYRTIN

¹ Department of Pharmacology, Howard University School of Medicine, Washington, D. C.

1. The m.c.d. and m.l.d. of coriamyrtin for frogs by injection into the dorsal lymph sac was 1 and 10 mgm. per kilogram.

2. The m.c.d. and m.l.d. 0.3 and 1 mgm. per kilogram subcutaneously for rats; 0.14 and 0.4 mgm. per kilogram for rabbits intravenously.

3. Rapid detoxification of coriamyrtin takes place in the body and cumulative effects are insignificant. Extended over a period of four hours one rabbit tolerated 9.6 or 2.4 times the m.c.d. and m.l.d., respectively; another 9.5 or 2.38 times the m.c.d. and m.l.d.; a third 4.6 or 1.1 times the m.c.d. and m.l.d. respectively.

4. In anesthetized cats and rabbits the blood pressure under coriamyrtin is but slightly affected; the respiration is powerfully stimulated both as to rate and volume. During a strong convulsion the volume may sometimes be reduced.

5. In unanesthetized rabbits rectal temperature under coriamyrtin drops 2 to 2.5°C.

6. From local application the heart of the turtle is unaffected; in the frog the rate of contractions is slowed and arrest in systole may occur in large concentrations. There is no strong chemical fixation of the drug to the heart muscle of cold-blooded animals.

7. Asphyxia is induced earlier in the mouse intoxicated with coriamyrtin than in the normal mouse. Results on rats are inconclusive.

8. Coriamyrtin has no distinct effect on the pupil or on the intraocular tension of the eyes of cats, rabbits and dogs when locally applied.

9. In the rabbit the blood sugar is increased 13 per cent above normal values.

10. Coriamyrtin convulsions are predominantly clonic but there is an admixture of the tonic type at the peak of a severe seizure.

11. In barbiturate intoxication coriamyrtin exhibits a high degree of antidotal effectiveness. It is more toxic, but less enduring and effective than picrotoxin and necessitates closer watchfulness.

12. A typical protocol and graphic records together with table of results are presented.

13. The literature pertinent to these investigations is discussed.