Description of the medicine: Caffeine (Coffeinum)
CAFFEINE (Coffeinum). 1, 3, 7-Trimethylxanthine.
Synonyms: Caffeine, Guaranin, Theinum.
The alkaloid contained in tea leaves (about 2%), coffee seeds (1 - 2%), cola nuts. Receive also synthetically.
White silky needle crystals or white crystalline powder of bitter taste, odorless. Slowly soluble in water (1:60), easy in hot (1: 2), hardly soluble in alcohol (1:50). Solutions have a neutral reaction; sterilized at + 100 C for 30 minutes
The structure and pharmacological properties of caffeine is close to theobromine (see) and theophylline (see); all three alkaloids belong to the group of methylxanthines.
Of these alkaloids, caffeine has the strongest stimulating effect on the central nervous system. Theophylline has a smaller effect, theobromine is even smaller; theophylline stimulates cardiac activity and diuresis more strongly, theobromine acts less, then caffeine. Due to these differences in potency, caffeine is used primarily as a central nervous system stimulant, and theophylline and theobromine are used as cardiovascular agents.
The physiological characteristics of the action of caffeine on the central nervous system were studied by I.P. Pavlov and his colleagues, who showed that caffeine enhances and regulates the processes of excitation in the cerebral cortex; in appropriate doses, it enhances positive conditioned reflexes and increases motor activity. The stimulating effect leads to an increase in mental and physical performance, a decrease in fatigue and drowsiness. Large doses can, however, lead to depletion of nerve cells. The effect of caffeine (as well as other psychostimulating agents) largely depends on the type of higher nervous activity; dosing of caffeine should therefore be made taking into account the individual characteristics of nervous activity. Caffeine weakens the effect of sleeping pills and drugs, increases the reflex excitability of the spinal cord, and stimulates the respiratory and vasomotor centers. Cardiac activity is enhanced by the influence of caffeine, myocardial contractions become more intense and more frequent. Under collapoid and shock conditions, blood pressure increases under the influence of caffeine, while normal blood pressure does not show significant changes, since simultaneously with the excitation of the vasomotor center and heart under the influence of caffeine, the blood vessels of skeletal muscles and other areas of the body expand (vessels of the brain, heart, kidneys ), however, the vessels of the abdominal organs (except the kidneys) narrow. Diuresis under the influence of caffeine is somewhat enhanced, mainly due to a decrease in the reabsorption of electrolytes in the renal tubules.
Caffeine lowers platelet aggregation.
Under the influence of caffeine, the secretory activity of the stomach is stimulated.