A brand of
acetaminophen
Tylenol is in 4 forms:
Tylenol, without a number, a non-prescription, over-the-counter
drug
Tylenol #2, a perscription drug with codeine. Usually 15mg. The label states WARNING:May cause drowsiness. Alcohol may intensify this effect. Use care when operating a car or dangerous machinery.
Tylenol #3 has codeine and is twice the dosage of Tylenol #2, 30mg. All the label says is don't take more than 1 every 3 or 4 hours, and then only as needed. Codeine can cause stomach irritation.
Tylenol #4 has codeine and is twice the dosage of Tylenol #3, 60mg The strongest, usually for extreme pain that the other dosages don't help for.
Tylenol shouldn't be taken very often, it can cause liver damage if you take it very often. One person is rumored to have taken it every day with a glass of wine. Both caused liver failure for him.
The codeine ones are usually used for broken bones or post-op patients. Too much codeine can caue stomach irritation, drowsiness, and in some cases hallucination. A board certified physician or pharmacist knows all the warnings and contraindications, and has a PDR. In the US and Canada, you need a prescription if its anything other than #1.