COMPARISON OF COCAINE AND SUBSTITUTES 193 



Propesin (propyl ester of para-amidobenzoic acid) occurs as a 

 white crystalline powder sparingly soluble in water. Its uses are 

 identical with those of anesthesin. 



^ Chloretone is a weak anesthetic and is not used to any extent for 

 this purpose in veterinary medicine. 



Dionin is soluble in 7 parts of water. It is used in 5 per cent, 

 solution to dilate the pupil, lessen intraocular tension and abolish 

 pain in the eye. It causes irritation and chemosis at first, which 

 soon disappears. On account of its irritant action it is classed as a 

 corneal lymphogogue and is useful in treating opacities of the cornea. 

 It may be used in 5 to 10 per cent, solutions or dionin may be dusted 

 in the eye. After several days, the eye becomes immune to the drug, 

 so that it must be discontinued for a time. 



Yohimbine is a local anesthetic when applied in 1 — 2 per cent, 

 solution. The effects begin in 10 to 15 minutes and last % — 1% 

 hours. The vessels are dilated even when used with adrenaline. 

 It should not be used in the eye because it produces too much irrita- 

 tion. (See aphrodisiacs.) 



Comparison of Cocaine and Its Substitutes. 



The most valuable features of cocaine are its strong, prompt and 

 quite certain action. It is also the best known of the group. It 

 is a vasoconstrictor, lessens hemorrhage, may be of service as a 

 mydriatic, causes no local irritation, and acts on sound mucous mem- 

 branes. 



The substitutes improve upon the older drug mainly by their lesser 

 toxicity, do not injure the cornea, are more stable, sterilizable and 

 antiseptic. Of the great mmiber of substitutes, novocaine appears 

 at the present time to be the most commendable; its feeble toxicity 

 permits large amounts to be used without inconvenience ; it has fairly 

 strong anesthetic properties, is nonirritant, and not a vasodilator. 

 Its only drawback is that its period of action is shorter than cocaine, 

 but this can be overcome by the addition of a small amount of adren- 

 aline solution. Keclus recommends the following solution : 



ISTormal salt solution 100 mils 



Novocaine 05 (50 centigrams) 



Adrenaline solution (1 — 1000) .... 25 drops 



The following table of relative toxicity was arrived at by the 

 Therapeutic Committee of the British Medical Association. Cocaine 

 is taken as the standard of comparison and is represented by 1. 



Alypine 1.25 



Cocaine 1-00 



Nirvanine 0.Y14 



Stovaine 0.625 



Tropococaine 0.500 



Novocaine 0.490 



Beta-eucaine lactate 0.414 



