Racial differences in mydriatic action of cocaine, euphthalmine, and ephedrine

Abstract

ONE FIGUREIn our investigation of the pupil-dilating effect of the natural or Z-ephedrine in subjects of different races, it was noted that the Chinese and negroes did not respond as well as Caucasians. This led to the examination of other mydriatics and the compilation of the present data to bring out actual racial differences as shown by the mydriatic action of cocaine, euphthalmine, I-ephedrine, dI-ephedrine, and d-pseudoephedrine.The observation period was one hour, because it was found that each drug reaches its maximal effect within sixty minutes. I n every case one or two drops of one of the solutions was applied locally to one conjunctival sac. The transverse diameter of the pupil was measured at the time of instillation and at the end of one hour.Preliminary studies in diffuse daylight uniformly bore out the point that Caucasians are more susceptible to the mydriatic action of cocaine, euphthalmine, I-ephedrine, dZ-ephedrine, and d-pseudoephedrine. Our next procedure was to repeat the experiments under controlled conditions and study the problem on a more quantitative basis. For this purpose, all observations were made in a dark room before a standard lamp having a light intensity of 13.3 candle power. The pupil was measured by its image in a telescope with a filar micrometer. Ten subjects were studied from each race for each drug. The average results are given in table 1 and contrasted in figure 1. They corroborate those obtained in diffuse daylight .

A comparison of drug protein binding and alpha 1‐acid glycoprotein concentration in Chinese and Caucasians.

“…While it is possible that presently unidentified factors may be contributory we believe the data support a racial difference in AAG concentration. Although racial differences in the mydriatic response to cocaine and ephedrine were noted over 60 years ago (Chen & Poth, 1929) differences in sensitivity to alcohol (Wolff, 1972) and more recently to propranolol (Zhou et al, 1989) have also been shown. It is important that in future such studies and kinetic studies in general evaluate the possible contribution of differences in drug binding when considering inter-ethnic differences.…”

Anestesia na população negra

“…A cútis do negro apresenta menor susceptibilidade ao efeito de substâncias irritantes ou alergia ao lá-tex, comuns nas dermatites de contato do pessoal paramédi-co 23,24 . O excesso de melanina na íris na musculatura radial e circular dificulta a ação de drogas midriátricas, como as antimuscarínicas (atropina) e α-adrenérgicas (fenilefrina e efedrina) 25,26 . O excesso de pigmentação da íris afeta o sistema trabecular e dificulta a drenagem do humor aquoso, determinando maior incidência de glaucoma (1:8) em relação ao branco (1:50).…”

“…Excessive melanin in the iris, radial and circular muscles impairs the action of mydriatric drugs such as antimuscarinic (atropine) and α-adrenergic (fenylephrine and ephedrine) drugs 25,26 . Excessive iris pigmentation affects the trabecular system and impairs aqueous humor drainage leading to a higher incidence of glaucoma (1:8) as compared to whites (1:50).…”

Racial differences in drug responses‐a comparative study of trimazosin and alpha 1‐adrenoceptor responses in normotensive Caucasians and West Africans.

“…For many years it has been recognised that racial factors may influence responsiveness to drugs, such as impaired mydriasis following standard doses of ephedrine and cocaine (Chen & Poth, 1929) and an insensitivity to atropine in Africans (Scott, 1945).…”