Certain medications, such as CYP inhibitors (eg, cimetidine) and oral contraceptives, impair caffeine metabolism. Caffeine clearance is reduced in patients with chronic liver disease, in pregnant women, and in infants. Caffeine clearance is increased in smokers. With smoking cessation, serum caffeine concentrations can double even if caffeine consumption remains stable. Oral doses of caffeine >10 g can be fatal in adults. A daily intake of 400 mg—about 4 or 5 cups of coffee—is considered safe for adults, while 200 mg is considered safe for pregnant women.
For more on caffeine toxicity, read here.
Medscape © 2018 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Richard H. Sinert. Fast Five Quiz: Test Your Knowledge of Caffeine Consumption, Toxicity, and Overdose - Medscape - Jan 26, 2018.