1. Caffeine is consumed in coffee, tea, soft drinks, and small amounts in chocolate.
2. It is the most widely used pharmacologically active substance in the world.
3. Caffeine can acutely raise blood pressure by 10 mmHg in patients who are infrequently exposed.
4. There is no effect on blood pressure in habitual coffee drinkers
5. It does not increase the risk of incident hypertension.
6.There is no evidence that caffeine in doses used in routine can provoke a spontaneous arrhythmia in individuals with or without a history of cardiac arrhythmia. There is no protective effect of caffeine abstinence also. In heart patients with coronary disease, the risk may be increased in individuals who are slow metabolizers of caffeine and drink two or more cups of coffee per day.
7. Ingestion of large quantities of caffeine is associated with arrhythmic and cardiovascular events, especially in patients with underlying cardiac disease.
8. Patients with a history of cardiac arrhythmia or at increased risk for cardiovascular events should moderate their caffeine intake from all sources.
9. Consumption of caffeinated beverages is associated with some short-term benefits like increased mental alertness and improved athletic performance.
10. Consumption of caffeinated beverages is associated with short term adverse effects including headache, anxiety, tremors, and insomnia.
11. In the long term, caffeine is also associated with generalized anxiety disorder, depression, and substance abuse disorders.
12. Long term benefits of caffeinated beverages are dose-dependent. Caffeine is associated with a reduced risk of Parkinson disease, Alzheimer disease, alcoholic cirrhosis, and gout.
13. Both caffeinated and decaffeinated coffee is associated with a lower risk of type 2 diabetes.
14. Several studies have linked coffee consumption with prevalence of various cancers.
15. The majority of studies show there may be a modest inverse relationship between coffee consumption and all-cause mortality.
16. Caffeine withdrawal is a well-documented clinical syndrome with headache being the most common symptom.