Vodka and painkillers I did a few shots of vodka a few hours ago and now my back is hurting. How long before I can take tylenol (acetaminophen)?

Whenever. As long as you are not making a habit out of it. The toxic dose of Acetaminophen (the active ingredient in tylenol (acetaminophen)) is more toxic together with alcohol, but it would take 2 extra strength tylenol (acetaminophen) four to six times a day before it might cause problems, unless your liver is already damaged. We metabolize about one drink per hour, so if a couple of hours have passed, there should be no problems.