Lipitor, which is a brand name for atorvastatin, is a medication that is used to lower cholesterol levels in the blood. According to Drug Patent Watch [1], Lipitor was approved by the US Food and Drug Administration (FDA) in 1996 and is manufactured by Pfizer.

One of the side effects of Lipitor is muscle pain, which can be experienced at night. This is a common side effect of statins, a class of drugs that Lipitor belongs to. According to an article published in Harvard Health Publishing [2], about 10% to 15% of people who take statins experience muscle pain or weakness.

However, the exact cause of statin-related muscle pain is not fully understood. A study published in the British Journal of Clinical Pharmacology [3] suggests that a genetic variation may be responsible for the muscle pain experienced by some people who take statins. The study found that people with a certain genetic variation were more likely to experience muscle pain when taking statins.

If you are experiencing muscle pain with Lipitor at night, it is important to talk to your doctor. Your doctor may recommend adjusting your dosage or switching to a different medication. In some cases, taking a coenzyme Q10 supplement may also help alleviate muscle pain associated with statin use.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.health.harvard.edu/pain/managing-statin-muscle-pain
[3] https://bpspubs.onlinelibrary.wiley.com/doi/full/10.1111/bcp.13887