Hello, With most of the statins usually muscle aches and some times muscle weakness is seen. Other side effects like dizziness, headache, feeling sick or tired can be seen. But most of the side effects last for a few days and are usually very mild. On continuation of therapy those effects mostly disappear. However, if you have been experiencing the kind of side effects (listed by you) you can consider discontinuing the drug. May be try it out after 2 to 3 weeks later. Again, if the same side effects do come then you may have to look at other options to reduce lipids. Even other statin molecules can be considered instead of simvastatin like Rosuvastatin. It is also good to talk to your concerned physician and decide. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Prabhakar Laxman Jathar, Diabetologist