Aston

Uses

Aston (amlodipine and atorvastatin) is used for patients for whom treatment with both amlodipine and atorvastatin is appropriate.

Atorvastatin is used for an adjunct to diet to reduce elevated total-C, LDL-C, apo B, and triglycerides (TG) levels and to increase HDL-C in patients with primary hypercholesterolemia (heterozygous familial and nonfamilial) and mixed dyslipidemia; as an adjunct to diet for the treatment of patients with elevated serum triglycerides (TG) levels; for the treatment of patients with primary dysbetalipoproteinemia who do not respond adequately to diet; to reduce total-C and LDL-C in patients with homozygous familial hypercholesterolemia as an adjunct to other lipid-lowering treatments (e.g. LDL apheresis) or if such treatments are unavailable. Prior to initiating therapy with atorvastatin, secondary cause for hypercholesterolemia (e.g. poorly controlled diabetes mellitus, hypothyroidism, nephritic syndrome, dysproteinemia, obstructive liver disease, other drug therapy, and alcoholism) should be identified and treated.

Amlodipine is used for the patients with mild to moderate hypertension (alone or in combination with other antihypertensives), the treatment of chronic stable and vasospastic angina, Raynaud's disease.

Aston is also used to associated treatment for these conditions: Anginal Pain, Cardiovascular Events, Chronic Stable Angina Pectoris, Coronary Artery Disease (CAD), High Blood Pressure (Hypertension), Homozygous Familial Hypercholesterolemia, Hypertension,Essential, Mixed Dyslipidemias, Primary Hypercholesterolemia, Vasospastic AnginaAnginal Pain, Cardiovascular Disease (CVD), Coronary Artery Disease (CAD), Coronary artery thrombosis, Dysbetalipoproteinemia, Fredrickson Type III lipidemia, Heterozygous Familial Hypercholesterolemia, High Blood Pressure (Hypertension), High Cholesterol, Homozygous Familial Hypercholesterolemia, Hospitalizations, Hypertriglyceridemias, Mixed Dyslipidemias, Mixed Hyperlipidemia, Myocardial Infarction, Non-familial hypercholesterolemia, Postoperative Thromboembolism, Primary Hypercholesterolemia, Stroke, Transient Ischemic Attack, Elevation of serum triglyceride levels, Heterozygous familial hyperlipidemia, Non-familial hyperlipidemia, Non-fatal myocardial infarction, Primary Hyperlipidemia, Revascularization procedures, Revascularization process, Thrombotic events, Cardiovascular Primary Prevention, Secondary prevention cardiovascular event

How Aston works

Mechanism of action on blood pressure

Amlodipine is considered a peripheral arterial vasodilator that exerts its action directly on vascular smooth muscle to lead to a reduction in peripheral vascular resistance, causing a decrease in blood pressure. Amlodipine is a dihydropyridine calcium antagonist (calcium ion antagonist or slow-channel blocker) that inhibits the influx of calcium ions into both vascular smooth muscle and cardiac muscle. Experimental studies imply that amlodipine binds to both dihydropyridine and nondihydropyridine binding sites, located on cell membranes. The contraction of cardiac muscle and vascular smooth muscle are dependent on the movement of extracellular calcium ions into these cells by specific ion channels. Amlodipine blocks calcium ion influx across cell membranes with selectivity. A stronger effect of amlodipine is exerted on vascular smooth muscle cells than on cardiac muscle cells . Direct actions of amlodipine on vascular smooth muscle result in reduced blood pressure .

Mechanism of action in angina

The exact mechanism by which amlodipine relieves the symptoms of angina have not been fully elucidated to this date, however, the mechanism of action is likely twofold:

Amlodipine has a dilating effect on peripheral arterioles, reducing the total peripheral resistance (afterload) against which the cardiac muscle functions. Since the heart rate remains stable during amlodipine administration, the reduced work of the heart reduces both myocardial energy use and oxygen requirements .

Dilatation of the main coronary arteries and coronary arterioles, both in healthy and ischemic areas, is another possible mechanism of amlodipine reduction of blood pressure. The dilatation causes an increase in myocardial oxygen delivery in patients experiencing coronary artery spasm (Prinzmetal's or variant angina) and reduces coronary vasoconstriction caused by smoking .

Atorvastatin is a statin medication and a competitive inhibitor of the enzyme HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase, which catalyzes the conversion of HMG-CoA to mevalonate, an early rate-limiting step in cholesterol biosynthesis. Atorvastatin acts primarily in the liver, where decreased hepatic cholesterol concentrations stimulate the upregulation of hepatic low-density lipoprotein (LDL) receptors, which increases hepatic uptake of LDL. Atorvastatin also reduces Very-Low-Density Lipoprotein-Cholesterol (VLDL-C), serum triglycerides (TG) and Intermediate Density Lipoproteins (IDL), as well as the number of apolipoprotein B (apo B) containing particles, but increases High-Density Lipoprotein Cholesterol (HDL-C).

In vitro and in vivo animal studies also demonstrate that atorvastatin exerts vasculoprotective effects independent of its lipid-lowering properties, also known as the pleiotropic effects of statins. These effects include improvement in endothelial function, enhanced stability of atherosclerotic plaques, reduced oxidative stress and inflammation, and inhibition of the thrombogenic response. Statins were also found to bind allosterically to β2 integrin function-associated antigen-1 (LFA-1), which plays an essential role in leukocyte trafficking and T cell activation.

Dosage

Aston dosage

Aston may be substituted for its individually titrated components. Patients may be given the equivalent dose of Aston or a dose of Aston with increased amounts of amlodipine, atorvastatin or both for additional antianginal effects, blood pressure lowering or lipid lowering effect.

Aston may be used to provide additional therapy for patients already on one of its components. As initial therapy for one indication and continuation of treatment of the other, the recommended starting dose of Aston should be selected based on the continuation of the component being used and the recommended starting dose for the added monotherapy.

Aston may be used to initiate treatment in patients with hyperlipidemia and either hypertension or angina. The recommended starting dose of Aston should be based on the appropriate combination of recommendations for the monotherapies.

The maximum dose of the amlodipine component of Aston is 10 mg once daily. The maximum dose of the atorvastatin component of Aston is 80 mg once daily.

Side Effects

In general, treatment with amlodipine and atorvastatin combination is well tolerated. Some common side effects include headache, dizziness, tiredness, sleepiness, stomach pain, nausea, stomach upset, diarrhea, edema, flushing, arrhythmia, palpitation, muscle and joint pain etc.

Toxicity

Acute oral toxicity (LD50): 37 mg/kg (mouse) .

Overdose

An overdose of amlodipine could result in a high degree of peripheral vasodilatation with a possibility of reflex tachycardia. Significant and prolonged hypotension leading to shock and fatal outcomes have been reported .

Carcinogenesis, mutagenesis, impairment of fertility

Rats and mice treated with amlodipine maleate in the diet on a long-term basis for up to 2 years demonstrated no evidence of a carcinogenic effect of the drug. For the mouse, the highest dose was comparable to the maximum recommended human dose of 10 mg amlodipine per day. For the rat, the highest dose was measured to be about twice the maximum recommended human dose .

Mutagenicity studies using amlodipine maleate showed no drug-related gene or chromosomal effects .

There was no impact on the fertility of rats given oral amlodipine maleate (males for 64 days and females for 14 days before mating) at doses up to 10 mg amlodipine/kg/day (8 times the maximum recommended human dose) .

Use in pregnancy

The safety of amlodipine in human pregnancy or lactation has not been proven. Amlodipine is therefore considered a pregnancy category C drug . Use amlodipine only if the potential benefit justifies the potential risk .

Use in nursing

Discontinue when administering amlodipine .

The reported LD50 of oral atorvastatin in mice is higher than 5000 mg/kg. In cases of overdose with atorvastatin, there is reported symptoms of complicated breathing, jaundice, liver damage, dark urine, muscle pain, and seizures. In case of overdose, symptomatic treatment is recommended and due to the high plasma protein binding, hemodialysis is not expected to generate significant improvement.

In carcinogenic studies with high doses of atorvastatin, evidence of rhabdomyosarcoma, fibrosarcoma, liver adenoma, and liver carcinoma were observed.

In fertility studies with high doses of atorvastatin, there were events of aplasia, aspermia, low testis and epididymal weight, decreased sperm motility, decreased spermatid head concentration and increased abnormal sperm.

Atorvastatin was shown to not be mutagenic in diverse mutagenic assays.

Precaution

Before instituting therapy with atorvastatin, an attempt should be made to control hypercholesterolemia with appropriate diet, exercise, and weight reduction in obese patients, and to treat other underlying medical problems. Information for Patients: Patients should be advised to report promptly unexplained muscle pain, tenderness, or weakness, particularly if accompanied by malaise or fever. Care should be taken in patients with renal failure, impaired hepatic function, and heart failure as amlodipine may deteriorate the conditions.

Interaction

Drug interaction with atorvastatin: The risk of myopathy during treatment with drugs of this class is increased with concurrent administration of cyclosporine, fibric acid derivatives, niacin (nicotinic acid), erythromycin, azole antifungals. When atorvastatin and antacid suspension containing magnesium and aluminum hydroxide were co administered, plasma concentrations of atorvastatin decreased approximately 35%. However, LDL-C reduction was not altered. Plasma concentrations of atorvastatin decreased approximately 25% when colestipol and atorvastatin were co administered. However, LDL-C reduction was greater when atorvastatin and colestipol were co-administered than when either drug was given alone. When multiple doses of atorvastatin and digoxin were co-administered, steady state plasma digoxin concentrations increased by approximately 20%. Patients taking digoxin should be monitored appropriately. In healthy individuals, plasma concentrations of atorvastatin increased approximately 40% with co- administration of atorvastatin and erythromycin. Co- administration of atorvastatin and an oral contraceptive increased AUC values for norethindrone and ethinylestradiol by approximately 30% and 20%. These increases should be considered when selecting an oral contraceptive for a woman taking atorvastatin.

Drug interaction with amlodipine: Amlodipine may potentiate the effect of other antihypertensive (e.g.Beta-blockers, ACE inhibitors, Alpha-1-blockers and Diuretics). In clinical interaction studies, Amlodipine did not affect the pharmacokinetics of Atorvastatin, Digoxin, Warfarin or Cyclosporine.

Volume of Distribution

21 L/kg , .

The reported volume of distribution of atorvastatin is of 380 L.

Elimination Route

Amlodipine absorbed slowly and almost completely from the gastrointestinal tract. Peak plasma concentrations are achieved 6-12 hours after oral administration. The estimated bioavailability of amlodipine is 64-90%. Steady-state plasma amlodipine levels are achieved after 7-8 days of consecutive daily dosing. Absorption is not affected by food .

Atorvastatin presents a dose-dependent and non-linear pharmacokinetic profile. It is very rapidly absorbed after oral administration. After the administration of a dose of 40 mg, its peak plasma concentration of 28 ng/ml is reached 1-2 hours after initial administration with an AUC of about 200 ng∙h/ml. Atorvastatin undergoes extensive first-pass metabolism in the wall of the gut and the liver, resulting in an absolute oral bioavailability of 14%. Plasma atorvastatin concentrations are lower (approximately 30% for Cmax and AUC) following evening drug administration compared with morning. However, LDL-C reduction is the same regardless of the time of day of drug administration.

Administration of atorvastatin with food results in prolonged Tmax and a reduction in Cmax and AUC.

Breast Cancer Resistance Protein (BCRP) is a membrane-bound protein that plays an important role in the absorption of atorvastatin. Evidence from pharmacogenetic studies of c.421C>A single nucleotide polymorphisms (SNPs) in the gene for BCRP has demonstrated that individuals with the 421AA genotype have reduced functional activity and 1.72-fold higher AUC for atorvastatin compared to study individuals with the control 421CC genotype. This has important implications for the variation in response to the drug in terms of efficacy and toxicity, particularly as the BCRP c.421C>A polymorphism occurs more frequently in Asian populations than in Caucasians. Other statin drugs impacted by this polymorphism include fluvastatin, simvastatin, and rosuvastatin.

Genetic differences in the OATP1B1 (organic-anion-transporting polypeptide 1B1) hepatic transporter encoded by the SCLCO1B1 gene (Solute Carrier Organic Anion Transporter family member 1B1) have been shown to impact atorvastatin pharmacokinetics. Evidence from pharmacogenetic studies of the c.521T>C single nucleotide polymorphism (SNP) in the gene encoding OATP1B1 (SLCO1B1) demonstrated that atorvastatin AUC was increased 2.45-fold for individuals homozygous for 521CC compared to homozygous 521TT individuals.[A181493] Other statin drugs impacted by this polymorphism include simvastatin, pitavastatin, rosuvastatin, and pravastatin.

Half Life

The terminal elimination half-life of about 30–50 hours .

Plasma elimination half-life is 56 hours in patients with impaired hepatic function, titrate slowly when administering this drug to patients with severe hepatic impairment .

The half-life of atorvastatin is 14 hours while the half-life of its metabolites can reach up to 30 hours.

Clearance

Total body clearance (CL) has been calculated as 7 ± 1.3 ml/min/kg (0.42 ± 0.078 L/ h/kg) in healthy volunteers , .

Elderly patients show a reduced clearance of amlodipine with an AUC (area under the curve) increase of about 40–60%, and a lower initial dose may be required .

The registered total plasma clearance of atorvastatin is of 625 ml/min.

Elimination Route

Elimination from the plasma occurs in a biphasic with a terminal elimination half-life of about 30–50 hours. Steady-state plasma levels of amlodipine are reached after 7-8 days of consecutive daily dosing . Amlodipine is 10% excreted as unchanged drug in the urine. Amlodipine can be initiated at normal doses in patients diagnosed with renal failure , .

Atorvastatin and its metabolites are mainly eliminated in the bile without enterohepatic recirculation. The renal elimination of atorvastatin is very minimal and represents less than 1% of the eliminated dose.

Pregnancy & Breastfeeding use

use in pregnant women clearly outweighs potential benefits.

Combination of amlodipine and atorvastatin, which includes atorvastatin, should be administered to women of childbearing age only when such patients are highly unlikely to conceive and have been informed of the potential hazards.

Lactation: Adequate human data are not available in case of lactation.

Use in children: There have been no studies conducted to determine the safety or effectiveness of combination of amlodipine and atorvastatin in pediatric populations.

Contraindication

Combination of amlodipine and atorvastatin is contraindicated in patients with known hypersensitivity to any component of this medication. Combination of amlodipine and atorvastatin contains atorvastatin and is therefore contraindicated in patients with active liver disease which may include unexplained persistent elevations of serum transaminases.

Special Warning

Patients with renal insufficiency: Renal disease has no influence on the plasma concentrations or lipid effects of Atorvastatin; thus no adjustment of dose is required. Hemodialysis is not expected to significantly enhance the clearance of Atorvastatin since the drug is extensively bound to plasma proteins.

Patients with hepatic dysfunction: In patients with moderate to severe hepatic dysfunction, the therapeutic response to Atorvastatin is unaffected but exposure to the drug is greatly increased.

Acute Overdose

Atorvastatin: There is no specific treatment for atorvastatin overdose. In the event of an overdose, the patient should be treated symptomatically, and supportive measures instituted as required. Due to extensive drug binding to plasma proteins, hemodialysis is not expected to significantly enhance atorvastatin clearance.

Amlodipine: There is no well documented experience with amlodipine overdosage. In case of clinically significant hypotension due to amlodipine over dosage, calls for active cardiovascular support including monitoring of cardiac and respiratory function, elevation of extremities and attention to circulating fluid volume and urine output. Since Amlodipine is highly protein-bound, dialysis is unlikely to be of benefit.

Interaction with other Medicine

Drug interaction with atorvastatin: The risk of myopathy during treatment with drugs of this class is increased with concurrent administration of cyclosporine, fibric acid derivatives, niacin (nicotinic acid), erythromycin, azole antifungals. When atorvastatin and antacid suspension containing magnesium and aluminum hydroxide were co-administered, plasma concentrations of atorvastatin decreased approximately 35%. However, LDL-C reduction was not altered. Plasma concentrations of atorvastatin decreased approximately 25% when colestipol and atorvastatin were co-administered. However, LDL-C reduction was greater when atorvastatin and colestipol were co-administered than when either drug was given alone. When multiple doses of atorvastatin and digoxin were co-administered, steady state plasma digoxin concentrations increased by approximately 20%. Patients taking digoxin should be monitored appropriately. In healthy individuals, plasma concentrations of atorvastatin increased approximately 40% with co-administration of atorvastatin and erythromycin. Co-administration of atorvastatin and an oral contraceptive increased AUC values for norethindrone and ethinylestradiol by approximately 30% and 20%. These increases should be considered when selecting an oral contraceptive for a woman taking atorvastatin.

Drug interaction with amlodipine: Amlodipine may potentiate the effect of other antihypertensive (e.g.Beta-blockers, ACE-inhibitors, Alpha-1-blockers and Diuretics). In clinical interaction studies, Amlodipine did not affect the pharmacokinetics of Atorvastatin, Digoxin, Warfarin or Cyclosporine.

Storage Condition

Store in a cool and dry place. Protect from light and moisture. Keep all medicines out of the reach of children.

Innovators Monograph

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