Sometimes the APAP (acetaminophen) itself causes nausea for me, but it you're just taking 650mg of APAP once that shouldn't be a problem for a normal liver. If you think that the APAP is contributing the nausea - like if you get nausea when you take APAP by itself - you could do a CWE, but it's kind of hard and a PITA to do a proper CWE on small amounts of pills.
To help with the nausea you can try:
- strong ginger root tea
- Gravol Natural Source Ginger Tablets (or another brand of ginger root/extract capsules/tablets)
- diphenhydramine, which is in Benadryl
- Gravol or Dramamine, which is dimenhydrinate (which is diphenhydramine plus theophylline)
- I don't know of any 2nd-generation antihistamines that can be bought OTC that don't contain other unwanted ingredients like pseudoephedrine, but maybe it varies depending on where you live?
- Being careful about what you eat and when. It seems to vary from person to person (some people find a full stomach makes them less nauseous, some find the reverse, certain foods set off nausea for some people, etc).
- Lying down not moving for a while, ideally with your back inclined on some pillows.
- If you smoke, try not to smoke much as it may worsen the nausea.
- Maybe try taking somes Tums or something if you can't get to a store right now and you have some on hand.
Often the nausea starts to get better after you have used the drug a few times.
Personally I find Gravol Natural Source Ginger Tablets to be more helpful than 25mg of Benadryl, and it doesn't have side effects.