Atorvastatin

Mechanism :

Atorvastatin is a synthetic lipid-lowering agent. Atorvastatin is an inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. This enzyme catalyzes the conversion of HMG-CoA to mevalonate, an early and rate-limiting step in cholesterol biosynthesis.

Indication :

• Hyperlipidemia

Contraindications :

Hypersensitivity to any component of this medication. Active liver disease or unexplained persistent elevations of serum transaminases exceeding 3 times the upper limit of normal.

Dosing :

Adverse Effect :

Diarrhea, arthralgia, insomnia, muscle cramps, myositis, myopathy, paresthesia, peripheral neuropathy, pancreatitis, hepatitis, cholestatic jaundice, anorexia, vomiting, alopecia, pruritus, rash, impotence, blood sugar abnormalities, increase in serum transaminase levels.

Interaction :

Concomitant Therapy with Other Lipid Metabolism Regulators: Combined drug therapy should be approached with caution as information from controlled studies is limited.
Bile Acid Sequestrants: Patients with Mild to Moderate Hypercholesterolemia: LDL-C reduction was greater when atorvastatin and colestipol were coadministered than when either drug was administered alone
Patients with Severe Hypercholesterolemia: LDL-C reduction was similar.
Fibric Acid Derivatives (Gemfibrozil, Fenofibrate, Bezafibrate) and Niacin (Nicotinic Acid): Although there is no experience with the use of atorvastatin given concurrently with fibric acid derivatives and niacin, the benefits and risks of such combined therapy should be carefully considered. The risk of myopathy during treatment with other drugs in this class is increased with concurrent administration.
Digoxin: Coadministration of multiple doses of atorvastatin and digoxin increased steady-state plasma digoxin concentrations.
Oral Contraceptives: Coadministration of atorvastatin with an oral contraceptive, increased plasma concentrations (AUC levels) of norethindrone and ethinyl estradiol.
Antacids: Administration of aluminium and magnesium-based antacids, with atorvastatin decreased plasma concentrations of atorvastatin by approximately 35%. LDL-C reduction was not altered but the triglyceride-lowering effect of atorvastatin may be affected.
Cimetidine: Administration of cimetidine with atorvastatin did not alter plasma concentrations or LDL-C lowering efficacy of atorvastatin, however, the triglyceride-lowering effect of atorvastatin was reduced.
Cytochrome P450-mediated Interactions: Atorvastatin is metabolized by the cytochrome P450 isoenzyme, CYP 3A4. Erythromycin, a CYP 3A4 inhibitor, increased atorvastatin plasma levels. Coadministration of CYP 3A4 inhibitors, such as grapefruit juice, macrolide antibiotics (including erythromycin), immunosuppressants (cyclosporine), azole antifungal agents (i.e., itraconazole, ketoconazole), or some antidepressants (e.g., nefazodone), may have the potential to increase plasma concentrations of HMG CoA reductase inhibitors, including atorvastatin. Caution should thus be exercised with concomitant use of these drugs.
Erythromycin: Plasma concentrations of atorvastatin increased approximately 40% with coadministration of atorvastatin and erythromycin, a known inhibitor of cytochrome P450 3A4.
Other Concomitant Therapy: Caution should be exercised with concomitant use of immunosuppressive agents and azole antifungals.
Drug/Laboratory Test Interactions: Atorvastatin may elevate serum transaminase and creatinine phosphokinase levels (from skeletal muscle). In the differential diagnosis of chest pain in a patient on therapy with atorvastatin, cardiac and noncardiac fractions of these enzymes should be determined.

Renal Dose :

Hepatic Dose :