176 CAFFEINE. 



CAFFEINE. 



Caffeine (C5H(CH ;5 )3N 4 O2 .HoO = 210.64) is a feebly basic substance derived 

 from the berries of Coffea Arabica and from the dried leaves of Thea Chinensis. 



Pharmacodynamics. 



Central Nervous System. Caffeine stimulates the entire system, but especially 

 the higher psychical functions. This effect is much more marked when a previous 

 depression exists. 



Muscular System. Irritatively stimulated. 



Respiration is increased and strengthened; centric action. 



Heart rate may be increased for short period from local irritation ; then later may 

 be slowed from centric inhibition. 



Blood-pressure may be increased slightly by centric vasoconstrictor action. 



Alimentary tract may be irritated by habitual use of caffeine. 



Secretory Glands. Caffeine stimulates the secretory epithelium of the kidney, and 

 increases circulation through the renal vessels. 



Metabolism is moderately stimulated. 



Temperature is elevated by centric action, with big doses only. 



Absorption is fairly rapid from gastro-intestinal tract. 



Excretion. Caffeine is eliminated in the urine, chiefly, in the form of urea and 

 some xanthin compounds. 



Tolerance may be attained to some degree. 



Symptoms. 



Moderate Doses. Large Doses. 



Heightened mentality, sensory side. Ringing in the ears. 



Diminished mentality, motor side. Sense of cerebral pressure. 



Restlessness and insomnia. Confusion of thought. 



Augmented physical ability. Great restlessness. 



Heightened sense of touch. Exaggerated spinal reflexes. 

 Increased pulse rate (by 6 to 8). 



Symptoms arising from chronic Caffeinism: 



Nervousness. Moodiness. 



Cardiac irregularities. Alternations of optimism and de- 

 Headache and insomnia. spondency. 



Irritability. Lassitude and indisposition. 



Therapeutics. 



Caffeine may be used advantageously as a respiratory stimulant, to combat de- 

 pressed conditions of the nervous system, and as a diuretic in dropsical conditions. 



Dosage. 



Caffeina, 0.03 to 0.15 Gm. 

 Caffeina citrata, 0.06 to 0.3 Gm. 



