Dose.—The dose of Ammonia is from gtt. v. to ʒss., largely diluted with water.
Therapeutic Action.—The local effects of Aqua Ammonia are energetic; applied to the surface it may act either as a rubefacient, vesicant, or caustic, according to the length of time and mode in which it is applied. Its vapor, when inhaled, acts as a powerful irritant to the mucous membranes of the air passages, and hence its utility in cases of syncope. By using it incautiously, however, in cases of insensibility, fatal results have occurred, the agent acting as an energetic caustic, producing inflammation and ulceration of the mucous membranes of the air passages. The effects in medicinal doses are those of a general stimulant, producing warmth in the stomach, transient vascular excitement, increased heat of the surface, and a disposition to diaphoresis, diuresis, and increased bronchial secretion. In some cases it affects the head, producing a sensation of fullness and oppression, but no pain. Its action upon the nervous system is evinced by the increased capacity to muscular exertion and activity, and the facility with which other functions are performed.
As a remedial agent it is useful in cases where we wish to rouse the action of the heart, without unduly exciting the brain, alleviate spasm and excite the respiratory organs, as in cases of asphyxia and syncope. It is an appropriate remedy in torpor or prostration, and sinking of the vital powers in typhoid or typhus fevers, and other adynamic forms of disease. In the cold stage of intermittents, especially of a congestive form, and in the exanthemata when the eruption has receded from the surface, its diaphoretic and stimulant powers render it an agent of much value. Diluents and warm clothing are required to promote its diaphoretic action.
As an antidote it is employed in cases of poisoning by the narcotics and sedatives, as the fox-glove, tobacco, and hydrocyanic acid; its efficacy depends, probably, upon its highly excitant action.
As an inhalation, the vapor of ammonia is used when a powerful shock to the nervous system is desirable, as in cases of syncope, asphyxia, and to ward off an attack of epilepsy. It is also employed to counteract the influence of anaesthetic agents; in fact, these agents are never employed without having the ammonia at hand, so as to be immediately available in case of accidents.
Antidotes.—In cases of poisoning by Ammonia, the antidotes are diluted acids, of which the best are vinegar, lemon or orange-juice. The consecutive inflammation is to be treated on general principles.