CAFFEINE. Formula C8H10N4HO2O2.
Related entry: Coffee
Occurrence—The proximate principle obtained from dry tea leaves, coffee, guarana sorbilis, and from some other plants.
Caffeine citrate is formed by the solution of caffeine in citric acid. It is probably a mixture of the two substances and not a chemical compound. It is a white powder, odorless, slightly bitter, and acid in reaction.
Mixed freely with water it is unstable and apt to precipitate. With only three parts of water it forms a syrupy solution, more permanent. When the precipitated liquid is increased by the addition of more than twenty-five parts of water, it will then remain in permanent solution.
Physiological Action—Caffeine acts upon the reflex centers of the spinal cord. It increases the temperature at first, afterwards diminishing it. It stimulates the cerebral functions, causing rapidity and facility of mental action. It produces nervousness and wakefulness. It has no true tonic effect. It raises the blood pressure and increases the pulse rate, acting as a direct stimulant to the muscle of the heart. It increases the solids in the urine by stimulating the epithelium of the tubules.
It actively stimulates the respiratory centers. This influence is required where there has been marked depression of the nervous system, and where motor depressants have been taken as poisons. It is given in conjunction with morphine to prevent any after depressing effect of this agent on the heart's action. It is given in many cases of headache, the effervescent citrate being a popular remedy, one used by the laity almost indiscriminately.
Therapy—Caffeine is a direct heart stimulant. It is given to support the heart in extreme feebleness or threatened failure. It is given in conjunction with remedies that are apt to have a depressing effect upon the heart, to sustain it against such depression. In feeble heart from dilatation, valvular insufficiency or fatty degeneration, and in dropsy resulting from the above conditions, with deficient capillary tonus, this agent is an excellent remedy.
In exhaustion from prostrating disease, with weak heart, this agent will exercise a positive influence in the general restoration of the patient, through its strengthening action on the heart.
It is given in some cases of asthma, where there is exhaustion from feebleness of the respiratory nerves.
It is given to dispel the drowsiness common to some individuals after eating a hearty meal. It is a remedy for melancholia, hypochondriasis and despondency.
It is a valuable remedy in general lithemic conditions, as it assists in elimination of urea and uric acid.
The main objection to the use of the remedy in these conditions is its inclination to produce persistent wakefulness. In extreme doses it sometimes producer, a mild form of delirium, with palpitation, general tremor and tinnitus aurium.
It is important in uremic coma, which causes depression of the heart and respiratory functions. It should be given hypodermically, in doses of from one-eighth to one-half a grain. It may be used in conjunction with other active eliminants.
Caffeine Citratis Effervescens—Effervescent citrate of caffeine. This popular combination for the administration of caffeine is made by triturating together a hundred and fifty-four grains each of caffeine and citric acid, eleven and a half ounces of bicarbonate of soda, ten and a half ounces of tartaric acid and twelve ounces of sugar, finely powdered. After thorough trituration, alcohol is added in sufficient quantity to make a soft paste. It is rubbed through a No. 6 galvanized iron sieve, and when dried is reduced to a coarse powder. It contains one per cent of caffeine. It is kept in a cool, dry place, in well-stoppered bottles, and is given in teaspoonful doses dissolved in a glass of water. It is a most pleasant method of administration. It is more commonly prescribed in the treatment of headaches, especially if caused by an acid condition of the stomach.
In mild cases of palpitation of the heart of a functional character, usually depending upon gastric derangement, this agent will be found advantageous.
The American Materia Medica, Therapeutics and Pharmacognosy, 1919, was written by Finley Ellingwood, M.D.
It was scanned by Michael Moore for the Southwest School of Botanical Medicine.