Lipitor is a brand name for the drug atorvastatin, which is a type of statin used to lower cholesterol levels in the blood [2][3]. According to Drug Patent Watch [1], there are no recommendations on how often a doctor should monitor patients taking Lipitor. However, the dosage of Lipitor may need to be adjusted depending on the patient's response to the medication, and regular blood tests may be necessary to monitor liver function and cholesterol levels [2][3].

Blood pressure medication, on the other hand, requires regular monitoring to ensure that the medication is working effectively and to check for any potential side effects [2]. The frequency of monitoring may vary depending on the type of medication and the patient's individual circumstances [2]. According to NHS Inform [2], patients taking blood pressure medication should have their blood pressure checked at least once a year. However, if the patient has high blood pressure or other health conditions, more frequent monitoring may be necessary [2].

In conclusion, there are no specific guidelines on how often a doctor should monitor patients taking Lipitor, but regular blood tests may be necessary to monitor liver function and cholesterol levels. Patients taking blood pressure medication should have their blood pressure checked at least once a year, but more frequent monitoring may be necessary depending on the patient's individual circumstances [1][2][3].

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.nhsinform.scot/tests-and-treatments/medicines-and-medical-aids/types-of-medicine/statins
[3] https://www.bhf.org.uk/informationsupport/heart-matters-magazine/medical/drug-cabinet/statins