Chocolate and cocoa contain not only caffeine but theobromine which is metabolised to caffeine prior to complete metabolism. Chronic, high caffeine intake, or toxicity, can result in headache, rhinorrhoea, nausea, anxiety, restlessness, irritability, dry mouth, tinnitus, palpitations, arrthythmius, tachypnoea, increased blood pressure, diuresis, sleep disruptions, gastrointestinal disturbances, and a variety of other symptoms. Deaths related to caffeine are uncommon, an individual would need to consume approximately 75 cups of coffee or 200 colas. Caffeine has also been reported to cause urticaria in susceptible individuals. Caffeine crosses into breast milk.
Clearance is decreased by liver disease, pregnancy, and contraceptive use.
Clearance is increased by smoking. Vitamin preparations and other tonics. G.A., Chafee F.H., Klein D.E. Aspirin Intolerance. A prospective study in an atopic and normal population. 4.Hillerdal G., Lindholm H. Laryngeal edema as the only symptom of hypersensitivity to salicylate acid and other substances.