BROMIDES 155 



BROMIDES 



The most common bromides used for narcotic effect are those of 

 potassium, sodium and ammonium, and to a small extent those of 

 lithium, strontium, calcium and zinc. Their characteristics are 

 similar. All occur as colorless crystals, or white granular powders, 

 of strong salty, bitter taste, are very soluble in water and moderately 

 soluble in alcohol, with the exception of that of potassium. The 

 dose is practically the same for each salt. 



Horses and cattle, gj — ij ; 30, 60. 



Dogs, grs. V — Ix; 0.3 — 4. 



Diluted (10 per cent.) hydrobromic acid is sometimes used for 

 the bromide action but has no advantage over the alkaline salts. 



Doses. H. 3 ij — vj ; 8. — 25. D. ITl x — xxx; 0.6 — 2. 



Physiological Action. The action of the bromides depends 

 both upon the bromine present and the other element of the com- 

 bination, since all are dissociable. Thus, each salt shows a certain 

 amount of variation from the others. The action of the bromine, 

 however, is distinctive, but the action of the other elements are also 

 distinctive. Since Potassium Bromide is most frequently employed 

 it will be discussed first and the difference between it and the others 

 pointed out later. 



External and Local Action. There is no effect upon the un- 

 broken skin. Upon raw surfaces and mucous membranes it has a 

 salt action and is irritant unless well diluted. If well diluted it is 

 slightly sedative to mucous membranes, and lessens reflex excita- 

 bility, especially of the pharynx. Before the days of cocaine, solu- 

 tions of the bromides were painted in the throat as mild anesthetics 

 to favor laryngeal examination. 



Digestive System. Potassium bromide causes irritation and 

 salivation due to its salty taste. Excessive doses may cause nausea 

 and looseness of the bowels. It is freely and rapidly absorbed, 

 traces being found in the urine within a few minutes after adminis- 

 tration. The salt is quite evenly distributed in the body but the chief 

 action is upon the nervous system. 



Nervous System. There is a moderate but lasting depression 

 on the whole nervous system that may be maintained for several 

 days with little if any effect upon the medullary centers. Potassium 

 bromide depresses the cerebrum diminishing the sense of pain and 

 special senses. Large doses cause drowsiness and favor sleep in the 

 human subject, but enormous doses will not force sleep in the day 

 time or if the patient is up and about. The motor areas in the 

 cortex are also depressed. Keflex activity is also lessened so that 

 the drug acts opposite to strychnine. The depression of the reflexes 

 gives a general depression of muscular tone throughout the body and 



