Overview
11 DESCRIPTION Atorvastatin is an inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. Atorvastatin calcium USP is (βR, δR)-2-(p-fluorophenyl)-β,δ-dihydroxy-5-isopropyl-3-phenyl-4(phenylcarbamoyl)pyrrole-l-heptanaote (1:2), trihydrate. The molecular formula of atorvastatin calcium USP is C 66 H 68 CaF 2 N 4 O 10 .3H 2 O and its molecular weight is 1209.41.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Atorvastatin is a selective, competitive inhibitor of HMG-CoA reductase, the rate-limiting enzyme that converts 3-hydroxy-3-methylglutaryl-coenzyme A to mevalonate, a precursor of sterols, including cholesterol. In animal models, atorvastatin calcium lowers plasma cholesterol and lipoprotein levels by inhibiting HMG-CoA reductase and cholesterol synthesis in the liver and by increasing the number of hepatic LDL receptors on the cell surface to enhance uptake and catabolism of LDL; atorvastatin calcium also reduces LDL production and the number of LDL particles. 12.2 Pharmacodynamics Atorvastatin, as well as some of its metabolites, are pharmacologically active in humans.
Indications
- 1 INDICATIONS AND USAGE Atorvastatin calcium tablets are indicated: To reduce the risk of: Myocardial infarction (MI), stroke, revascularization procedures, and angina in adults with multiple risk factors for coronary heart disease (CHD) but without clinically evident CHD MI and stroke in adults with type 2 diabetes mellitus with multiple risk factors for CHD but without clinically evident CHD Non-fatal MI, fatal and non-fatal stroke, revascularization procedures, hospitalization for congestive heart failure, and angina in adults with clinically evident CHD As an adjunct to diet to reduce...
Common Doses
- 20 mg
- 10 mg
- 80 mg
- 40 mg
Dosage
2 DOSAGE AND ADMINISTRATION Take orally once daily with or without food ( 2.1 ). Assess LDL-C when clinically appropriate, as early as 4 weeks after initiating atorvastatin calcium tablets, and adjust dosage if necessary ( 2.1 ). Adults ( 2.2 ): Recommended starting dosage is 10 or 20 mg once daily; dosage range is 10 mg to 80 mg once daily. Patients requiring LDL-C reduction >45% may start at 40 mg once daily. Pediatric Patients Aged 10 Years of Age and Older with HeFH: Recommended starting dosage is 10 mg once daily; dosage range is 10 to 20 mg once daily ( 2.3 ).
Contraindications
- 4 CONTRAINDICATIONS Acute liver failure or decompensated cirrhosis [see Warnings and Precautions (5.3) ] Hypersensitivity to atorvastatin or any excipients in atorvastatin calcium. Hypersensitivity reactions, including anaphylaxis, angioneurotic edema, erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis, have been reported [see Adverse Reactions (6.2) ]. Acute liver failure or decompensated cirrhosis ( 4 ). Hypersensitivity to atorvastatin or any excipient in atorvastatin calcium ( 4 ).
Side Effects
- 6 ADVERSE REACTIONS The following important adverse reactions are described below and elsewhere in the labeling: Myopathy and Rhabdomyolysis [see Warnings and Precautions (5.1) ] Immune-Mediated Necrotizing Myopathy [see Warnings and Precautions (5.2) ] Hepatic Dysfunction [see Warnings and Precautions (5.3) ] Increases in HbA1c and Fasting Serum Glucose Levels [see Warnings and Precautions (5.4) ] Most common adverse reactions (incidence ≥5%) are nasopharyngitis, arthralgia, diarrhea, pain in extremity, and urinary tract infection ( 6.1 ).
Interactions
- 7 DRUG INTERACTIONS See full prescribing information for details regarding concomitant use of atorvastatin calcium with other drugs or grapefruit juice that increase the risk of myopathy and rhabdomyolysis ( 2.5 , 7.1 ). Rifampin: May reduce atorvastatin plasma concentrations. Administer simultaneously with atorvastatin calcium ( 7.2 ). Oral Contraceptives: May increase plasma levels of norethindrone and ethinyl estradiol; consider this effect when selecting an oral contraceptive (7.3 ). Digoxin: May increase digoxin plasma levels; monitor patients appropriately ( 7.3 ). 7.