Question
Hello doctor, how long does it take for epilepsy medication to take effect? I’ve been taking the medication but I still have seizures, what’s going on?
Answer
Epilepsy medications do not take effect immediately. Antiepileptic drugs pass through the mouth, esophagus, stomach, small intestine, and then the colon mucosa before being absorbed into the blood. They then circulate through the bloodstream to the brain, where they form a stable blood drug concentration to exert a therapeutic effect. The concentration of the drug in the blood that forms a relatively stable level is called the “steady-state concentration,” and the time required to reach this level is five and a half half-lives of the drug. The time it takes for each antiepileptic drug to reach steady-state concentration varies, and it generally takes about 7-10 days to observe whether the medication is effective. One should never arbitrarily add or change medications just after 3-5 days, when the medication has not yet taken effect.