While it is possible, it is not probable, says Joshua Cohen, MD, MPH, a headache specialist at the New York-based Headache Institute at St. Luke’s-Roosevelt Hospital Center. As much as people who suffer from the debilitating head-twisting headaches known as migraines may be desperate for relief, many resist going on prescription medications (which may help to treat, prevent, or at least decrease the frequency and severity of headaches). Why? They fear they’ll come to depend on the meds only to discover (in horror) one day that they’ve stopped working.

While there is a very real process, known as tachyphylaxis, by which some medications, when taken either a short while or regularly over a long period of time, either no longer are effective or require much higher doses to maintain the same potent results, it is not common that this will occur with migraine medications, says Cohen. The migraine medication most susceptible to tachyphylaxis, says Cohen, is metoclopramide (brand names Maxolon, Metozolv, and Reglan), an anti-nausea medicine that can treat both the headache and the nausea that can accompany the migraine. Still, the majority of people who take prescription medications for migraine, says Cohen, will experience stable and consistent results over time.

Much more of a concern for people suffering from migraines who are considering beginning a prescription drug regimen than drug resistance over time are possible side effects and/or interactions with other prescription drugs you may already be taking. Be sure to discuss a migraine medication fully with your doctor before making the decision to start taking it. If, however, you have been taking a migraine preventive medication and suddenly start to notice an increase in the frequency, severity, or duration of attacks, contact your doctor, who can determine whether tachyphylaxis or another root cause is at work.