• Atorvastatin may be used for the treatment of high cholesterol.
• Atorvastatin works by blocking an enzyme, called HMG-CoA reductase, in the liver that makes different types of lipids (this is the collective term for fats and cholesterol). Atorvastatin also boosts the breakdown of lipids.
• Atorvastatin belongs to the class of medicines known as statins. Atorvastatin is also known as an HMG-CoA reductase inhibitor.

• Atorvastatin, in conjunction with dietary measures, may be used for the treatment of high cholesterol in people at increased risk of cardiovascular disease if initial dietary measures fail to lower cholesterol.
• Atorvastatin is also used to lower the risk of coronary events (such as a heart attack, stroke, or angina) in patients at high risk of these events. This includes people with pre-existing coronary heart disease, diabetes, peripheral vessel disease, a previous history of stroke and stroke-like events or heart attack, or with multiple risk factors (such as older age, smoking, high blood pressure, low HDL-C, or a family history of heart disease).
• Possibly more effective than other statins, apart from rosuvastatin.
• Generic atorvastatin is available.

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

• Nasopharyngitis (swelling of the nasal passages and back of the throat), arthralgia (joint pain), diarrhea, dyspepsia, pain, and urinary tract infections.
• Muscle pain, tenderness, or weakness. Initially, this needs further investigation to rule out more serious muscle effects (such as rhabdomyolysis - the destruction of muscle cells). People aged older than 65, taking certain medications (for example cyclosporine, itraconazole, HIV antivirals), who drink more than two alcoholic drinks per day, or with kidney disease appear more at risk of serious side effects.
• Atorvastatin, like other statins, may affect liver function, manifesting as changes in liver function tests or jaundice (yellowing of the skin) requiring dosage reduction or discontinuation.
• May also affect some diabetes markers (such as HbA1c or fasting glucose), and may not be suitable for those with liver or kidney disease, or those who have recently had a stroke or a TIA (transient ischemic attack).
• Rarely, has been associated with memory loss, forgetfulness, amnesia, memory impairment, and confusion. These symptoms typically resolve with discontinuation.
• May interact with several other medications including those metabolized by hepatic enzymes CYP 3A4, clarithromycin, protease inhibitors, cyclosporine, gemfibrozil, oral contraceptives, and digoxin.
• Do not use atorvastatin during pregnancy, and women who are taking atorvastatin should not breastfeed. If taken during pregnancy, atorvastatin may interfere with the synthesis of steroids and cell membranes in the fetus.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

• Take once daily. May be taken at any time of the day (morning or night); however, it is best to be consistent with the time you take your tablets.
• The dosage of atorvastatin needs to be individualized but initially should start at 10-20 mg/day and be guided by the results of cholesterol tests taken 2 to 4 weeks later. Take atorvastatin exactly as directed by your doctor. Do not increase or decrease the dosage without his or her advice.
• Avoid drinking large quantities of grapefruit juice or eating grapefruit or grapefruit products while taking atorvastatin.
• Limit your alcohol intake and avoid drinking more than two glasses of alcohol per day while you are taking atorvastatin.
• Seek urgent medical advice and consider temporarily withholding atorvastatin if you develop any acute muscle pain or have another condition that may increase your risk of serious muscle injury or kidney failure such as a severe infection, major surgery, trauma, uncontrolled seizures, severe electrolyte or metabolic disorders.
• Adhere to the TLC diet, designed by the National Cholesterol Education Program (NCEP), or a similar diet, while taking atorvastatin.
• Plan to exercise regularly and stop smoking if you smoke. Try to avoid second-hand smoke.
• See your doctor straight away if you notice any yellowing of your skin or shortness of breath, unexplained cough, or general tiredness. 
• Atorvastatin should not be taken during pregnancy or while breastfeeding. Ensure you use effective contraception while taking atorvastatin if you are a woman of childbearing age and talk to your doctor if you intend to become pregnant before you become pregnant.

• Peak levels of atorvastatin are seen within one to two hours following administration; however, it may take one to two weeks of regular dosing before improvements in your cholesterol levels are seen, and up to four weeks before the maximal cholesterol-lowering effects of atorvastatin are apparent.  
• May lower total cholesterol by 30-46% and triglycerides by 30-56%, with variable increases seen in HDL.  
• Possibly more effective than other statins.

Medicines that interact with atorvastatin may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with atorvastatin. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with atorvastatin include:

• amiodarone
• antibiotics, such as erythromycin
• antidepressants, such as nefazodone
• antifungals, such as itraconazole, ketoconazole, posaconazole, or voriconazole
• bezafibrate
• calcium channel blockers such as amlodipine, diltiazem, or verapamil
• colchicine
• cyclosporine
• digoxin
• gemfibrozil
• grapefruit juice
• HIV medications such as tipranavir, ritonavir or pibrentasvir
• niacin
• oral contraceptives
• other lipid-lowering drugs such as gemfibrozil and bezafibrate
• strong CYP3A4 inducers such as efavirenz or rifampin
• strong CYP3A4 inhibitors, such as clarithromycin or cyclosporine
• warfarin.

Note that this list is not all-inclusive and includes only common medications that may interact with atorvastatin. You should refer to the prescribing information for atorvastatin for a complete list of interactions.