An opiate is a type of drug that acts on the opiate receptors in your body. Some of the more common ones are:
- Tramadol
- Codeine
- Morphine
- Hydrocodone
- Oxycodone
- Oxymorphone
- Heroin
- Fentanyl
Opiates are useful as pain killer but can also be abused for their euphoric and sedative effects. Abusing them is also dangerous however because if you take too many you will fall asleep and stop breathing. Check out the wikipedia article on them here.
http://en.wikipedia.org/wiki/Opiate
Because different opiates work on the same receptors on the brain, if you build up a tolerance to one you also build up a tolerance to the other ones.
Vicodin 10s contain 10mg of hydrocodone which is a medium strength opiate, while according to selio the Tylenox 750 contains 7.5mg of oxycodone which is about twice as strong.
If you usually take 50mg of hydrocodone you should probably try and start off with about 20mg of oxycodone.
Once again just to make sure though why don't you read the label of the Tylenox 750 bottle and tell me what the active ingredients are and how many milligrams are in each pill.
Acetaminophen:
Regarding the acetaminophen, consuming more than 3-4g (3 to 4 thousand mg) at once or less than that consistently is extremely bad for your liver. You need to remove the acetaminophen (also known as APAP or paracetamol) by using a cold water extraction or CWE. Check out this thread here.
Cold Water Extraction Mega Thread & FAQ v2.0