Chinese Journal of Physiology

THE EPHEDRINES ON NASAL MUCOSA 103

The ratio of duration of effect was:

Ps-ephedrine = 0.40.

Ephedrine Three minutes after injection of ephedrine the blood pressure diminished to 62 per cent of the maximal rise of blood pressure and to 20 per cent for pseudoephedrine. V. The comparison of ephedrine, ephetonin and pseudoephedrine.

Combining the results obtained in II, II] and 1V we deduce the following ratios:—

Ephedrine Ephetonin Pseudoephedrine

a, Maximal effect on nasal volume: iL 0.76 0.38 132). 1 0.50 2.67 2.01 1 b. The duration of shrinkage of the mucosa: 1 0.80 0.68 c. Blood pressure effect of small doses (0.2 mg per kg): 1 0.68 0.56 d. The duration of the blood pressor action: lh 0.66 0.48 DISCUSSION

Seeing that ephetonin does not have as great an effect in contracting the nasal mucous membranes, when applied locally to obtain a maximum effect more is needed than when ephedrine is used. This suggests a further study of the local action of varying concentrations of these drugs.

The fact that there is definite contraction of the membranes both with ephetonin and pseudoephedrine, makes it possible to substitute them for ephedrine should the latter drug have undue untoward effects or in any other way be contraindicated.

CONCLUSIONS

1, Like ephedrine both pseudoephedrine and ephetonin cause a distinct and sustained shrinkage of the nasal mucous membrane.

2. The relative strengths of the vasoconstrictor effect of the three isomers are:

Ephedrine: Ephetonin: Pseudoephedrine = 1: 0.76: 0.38.

3. Their durations of shrinkage has the ratio:

Ephedrine: Ephetonin: Pseudoephedrine = 1: 0.8: 0.7.

4. The nasal plethysmographic method is suitable for the bio-assay of the vasoconstrictor action of ephedrine.