Any over-the-counter medication whose name ends in "ine" should be checked in a flight medical examiner for use before flying. Beware of any medicine that is supposed to make you feel better. At altitude the effects may be damaging to flight safety.
Medicine taken is just as likely, even more likely, to be the basis for grounding a pilot than is the ailment itself. Medicinal side effects are both variable and unpredictable. Virtually all medications have side effects. Never take a medication for the first time and then fly. Make the safe decision if you are sick.