(used before a noun) Having prescription medication on hand so as to treat an illness as soon as one or more symptoms present themselves. (Sometimes not hyphenated and put in quotation marks instead.) Doctors are hopeful that a pill-in-the-pocket approach might be effective in managing this patient's paroxysmal atrial fibrillation, if he takes one dose of the trial drug at the onset of palpitations. While it removes the necessity for patients to remember their pill every day, "pill in the pocket" systems of treatment are limited by the fact that patients must have their medication with them at all times.