1. something that is to happen or has happened to a particular person or thing; lot or fortune. 2. the predetermined, usu. inevitable, course of events. 3. the power or agency that determines the course of events.
Alternating between ibuprofen and acetaminophen every 2 hours because you have to wait 4 hours for each of them to take a second dose of the same thing. So instead you take a dose of Acetaminophen now, then Ibuprofen in 2 hours and back to Acetaminophen 2 hours later as needed.
In addition, they are both available over-the-counter in low doses and via prescription in higher doses. However, the effects of ibuprofen do not tend to last as long as Aleve, so you may have to take it every four to six hours (up to six times a day). Aleve only has to be taken up to three times a day, or every eight hours.