... CAFFEINE (Enerjets®, NoDoz®, Snap-Back®, Stay-Alert®, Vivarin®) acts as a central nervous system (CNS) or brain stimulant, increasing alertness in people who are tired or sleepy. Caffeine occurs naturally in tea, coffee, cocoa, and chocolate, and is added to many soft drinks. Generic forms of caffeine are available, and can be obtained without a prescription. ...
Drug Digest - more...

Vivarin is an over-the-counter caffeine tablet from GlaxoSmithKline which is used to restore mental alertness or wakefulness when experiencing fatigue or drowsiness. Vivarin contains 200 mg. of caffeine per tablet or caplet, approximately the same amount of caffeine found in a cup of coffee. ...
Wikipedia - [full article]

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