How come "cold" and "flu" medicines make you sleepy ?

Antihistamine: Most such preparations include an antihistamine, which cause drowsiness in many people.

Antihistamines can: cause drowsiness. If you have the Flu hydrate well w water, herbal teas, soup or juice. Drink sufficiently to have pale to light yellow urine. You can use pain relievers like Tylenol (acetaminophen) or NSAID’s. Rest A LOT! In some situations antiviral medications (Tamiflu, Relenza, Flumadine) may be prescribed within the first couple of days of symptoms to hasten healing or they can be used after flu exposure to