See the DrugPatentWatch profile for lipitor

Based on the information available, there is no specific timeframe for Lipitor's loss of efficacy. Lipitor, a medication used to treat high cholesterol, maintains its effectiveness as long as it is taken as directed. However, its effectiveness can be influenced by various factors such as diet, lifestyle, and individual genetic makeup [1].

Once a patient stops taking Lipitor, their cholesterol levels may rise again over time. This is because Lipitor works by blocking the action of a specific enzyme in the body that is needed to make cholesterol [2]. When the medication is no longer present in the body, the production of cholesterol may increase, leading to a rise in cholesterol levels.

It is important to note that Lipitor's patent expired in 2011, which led to the introduction of generic versions of the drug [3]. The availability of generics has made Lipitor more accessible and affordable for patients.

In conclusion, while there is no specific timeframe for Lipitor's loss of efficacy, its effectiveness can be influenced by various factors. Once a patient stops taking Lipitor, their cholesterol levels may rise again over time.

Sources:
[1] Mayo Clinic. (2021). Atorvastatin (Oral Route). Retrieved from https://www.mayoclinic.org/drugs-supplements/atorvastatin-oral-route/description/drg-20063056
[2] National Library of Medicine. (2021). Atorvastatin. Retrieved from https://medlineplus.gov/druginfo/meds/a601243.html
[3] DrugPatentWatch. (2021). Lipitor (Atorvastatin Calcium). Retrieved from https://www.drugpatentwatch.com/drugs/lipitor