Lipitor is a medication primarily used to lower cholesterol levels in the body. It belongs to a class of drugs called statins, which work by inhibiting an enzyme involved in cholesterol production. The effectiveness of Lipitor in reducing cholesterol levels varies from person to person, and there is no specific timeframe for its effectiveness.

According to the information provided by Drug Patent Watch, Lipitor's patent expired in 2011 [1]. This means that generic versions of the drug are available, and it has been on the market for several years. The expiration of a patent does not necessarily indicate a decrease in effectiveness, but rather allows other manufacturers to produce and sell generic versions of the medication.

A study published in the Journal of the American Medical Association (JAMA) examined the effectiveness of Lipitor in reducing LDL cholesterol levels. The study found that after six weeks of treatment, Lipitor significantly reduced LDL cholesterol levels compared to a placebo [2]. However, it is important to note that individual responses to the medication may vary, and the duration of treatment required to achieve desired cholesterol levels can differ from person to person.

It is worth mentioning that Lipitor is typically prescribed as a long-term treatment for managing cholesterol levels. The duration of treatment is determined by the individual's specific medical condition, risk factors, and response to the medication. Lipitor is often used as part of a comprehensive approach to managing cholesterol, which includes lifestyle changes such as a healthy diet and regular exercise.

In conclusion, there is no specific timeframe for Lipitor's effectiveness in reducing cholesterol levels. The effectiveness of the medication varies from person to person and depends on various factors. It is important to consult with a healthcare professional for personalized advice regarding the duration and effectiveness of Lipitor treatment.

Sources:
[1] Drug Patent Watch. Lipitor. Retrieved from https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] Nissen, S. E., et al. (2002). Effect of Atorvastatin on the Occurrence of Cardiovascular Events in Patients With Atherosclerotic Cardiovascular Disease. JAMA, 288(23), 2981-2997. doi:10.1001/jama.288.23.2981