Side effects of atorvastatin may vary from person to person. Some mild side effects may appear within the first days or weeks of treatment. Muscle pain, fatigue, or digestive complaints are often noticed early. However, effects such as elevated liver enzymes may not cause symptoms and may only be detected through blood tests. This makes regular monitoring important. If severe muscle pain, dark urine, jaundice, or significant fatigue occurs, a physician should be consulted before stopping or changing the medication.