How long can the side effects of use last?

You did not write what drug you are talking about. If you have Mysimba, please read on. Headache is a side effect that occurs very often when you are taking Mysimba. With a frequency of no more than 1 in 10 people, there may be a feeling of fatigue, drowsiness, dizziness, a feeling of spinning. Side effects occur during the use of the drug and should not persist for a long time after discontinuation. After the end of the treatment, the concentration of active ingredients in the body systematically decreases. Naltrexone should be eliminated from the body after about a day, and bupropion after about 5 days. That's how long it takes for about five half-lives to pass - after each of them, the concentration of the substance drops by half. If after a week you still feel severe ailments, it is worth consulting a doctor. I enclose additional information: https://www.gdziepolek.pl/artykuly/jak-i-dlaczego-zglaszac-dzialania-niepozadane