Caffeine Intoxication 505
Prevalence
The prevalence of caffeine intoxication in the gene ral population is un clear. In the United
States, approximately 7% of individuals in the population may experience five or more symp-
toms along with functional impairment consiste nt with a diagnosis of caffeine intoxication.
Development and Course 
Consistent with a half-life of caffeine of approximately 4–6 hours, caffeine intoxication
symptoms usually remit within the first day or  so and do not have any known long-lasting
consequences. However, individuals who consum e very high doses of caffeine (i.e., 5–10
g) may require immediate medical attent ion, as such doses can be lethal.
With advancing age, individuals are likely to demonstrate increasingly intense reac-
tions to caffeine, with greater complaints of interference with sleep or feelings of hyper-
arousal. Caffeine intoxicati on among young individuals after consumption of highly
caffeinated products, includin g energy drinks, has been observed. Children and adoles-
cents may be at increased risk for caffeine into xication because of low body weight, lack of
tolerance, and lack of kn owledge about the pharmacolog ical effects of caffeine.
Risk and Prognostic Factors
Environmental. Caffeine intoxication is often seen among individuals who use caffeine
less frequently or in those who have recently increased their caffeine intake by a substan-
tial amount. Furthermore, oral contraceptives significantly de crease the elimination of caf-
feine and consequently may incre ase the risk of intoxication. 
Genetic and physiological. Genetic factors may affect risk of caffeine intoxication.
Functional Consequences of Caffeine Intoxication
Impairment from caffeine intoxication may have serious consequences, including dys-