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 this instance, it's okay to give acetaminophen a try now. In fact, because you can't give her ibuprofen again for six to eight hours after the first dose, it may be helpful to try a new tack. If the acetaminophen does the trick, your child won't need any medication at all for another six to eight hours. It's not a good idea, though, to get in the habit of giving your child alternating doses of ibuprofen and acetaminophen, because ongoing alternating doses can be hard on the kidneys.