Adults

Initial dose is typically 10 mg or 20 mg once daily. Dosage range is 10 mg to 80 mg once daily. Doses should be individualized according to the patient's lipid levels, goals of therapy, and response. Lipid levels should be assessed within 2 to 4 weeks of initiation and dose adjusted accordingly.

Elderly

No specific dose adjustment is required based on age. However, caution should be exercised in elderly patients due to potential increased risk of myopathy.

Renal_impairment

No dose adjustment is necessary for patients with renal impairment.

Onset

Lipid-lowering effects typically observed within 2 weeks, maximal effect usually within 4 weeks.

Excretion

Primarily excreted in the bile following hepatic and/or extrahepatic metabolism. Less than 2% is recovered in the urine.

Half life

Approximately 14 hours for the parent drug. Active metabolites contribute to an effective half-life of 20 to 30 hours.

Absorption

Rapidly absorbed after oral administration, with peak plasma concentrations occurring within 1 to 2 hours. Absolute bioavailability is low (approximately 12%) due to extensive presystemic clearance in the gastrointestinal mucosa and/or hepatic first-pass metabolism.

Metabolism

Extensively metabolized in the liver by cytochrome P450 3A4 (CYP3A4) to active ortho- and parahydroxylated metabolites and various beta-oxidation products.

0

CYP3A4 Inhibitors (e.g., macrolide antibiotics, azole antifungals, protease inhibitors): May increase atorvastatin plasma concentrations, increasing risk of myopathy/rhabdomyolysis.

1

Gemfibrozil, Other Fibrates, Niacin: Increased risk of myopathy/rhabdomyolysis when co-administered with statins.

2

Warfarin: Atorvastatin may slightly increase INR (International Normalized Ratio) in patients on chronic warfarin therapy; monitor INR.

3

Oral Contraceptives: Atorvastatin may increase plasma concentrations of norethindrone and ethinyl estradiol.