Table of Contents
Uses of Norvasc
Norvasc is one of the brand names that are used to describe the Amlodipine drug. The drug is mainly used in the treatment of individuals with high blood pressure. The other application of the drug includes the treatment of diseases of the coronary artery. Since the inhibits the transportation of calcium ions through the channels, Amlodipine is in most cases only used in the treatment of heart failures when the alternative drugs are not able to fully combat high blood pressures or thoracic pains that may result from heart related problems. The drug is a long term medication that blocks the calcium channel. The drug also operates by slightly enlarging the arteries (Wang, Yan & Jeffers, 2014). Some of the minor side effects that may result from using the drug include inflammation of the tissues in different body parts, tiredness, abdominal discomfort, and nausea. The other major side effects may involve lowered blood pressure to critical levels, which may lead to heart attack in the patient. The dosage of Amlodipine ought to be kept to a minimum in individuals having liver related issues, and the aged persons. There is however inconclusive evidence over the suitability of the use of the drug in pregnant women or during breastfeeding.
History of Norvasc
The patent of the drug was first issued in the year 1986, while the production for commercial purposes began in the year 1990. The protection that the Norvasc medication had through the Pfizer company’s patent expired in 2007. Furthermore, the complete expiration occurred in the same year. There are currently many generic forms of the Amlodipine drugs that are commercially used. The overall abilities of the generic versions depend on the content of the amlodipine contained in them. For instance, a majority of the generic versions are produced with additional salts (Mertig, 2012). Norvasc has currently been listed among some of the essential medications that have received global recognition. Furthermore, it has been identified as one of the drugs required for a complete health system to be maintained.
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Characteristics of the Drug
Norvasc medications mainly consists of the Besylate Amlodipine. The drug is universally known by the standard name as 3-O-ethyl 5-O-methyl 2-(2-aminoethoxymethyl)-4-(2-chlorophenyl)-6-methyl-1,4-dihydropyridine-3,5-dicarboxylate (Muntner et al., 2014). The drug can also be physically described as follows.
The structural component with the Nitrogen element gets to be oxidized, while the 2 rings on either side of the structure get to be hydrolyzed during the metabolism.
Physical Properties
The weight of the Amlodipine molecule is about 408.88 grams per unit mole. In normal conditions, the drug is found in solid state and has a melting point of 179 degrees. The drug can dissolve in water at room temperature to form a concentration of 75.3 milligrams per unit liter. Furthermore, the drug shows good stability under normal conditions. When subjected to combustion, the drug can emit hazardous chemicals such as oxides of nitrogen, sulfur and carbon. Norvasc is available in tablets that are administered orally. The tablets have Amlodipine weights of 2.5, 5, and 10 milligrams. The Amlodipine Besylate is characterized by a white appearance, and is crystalline in nature. The other constituents of the tablet include Cellulose and magnesium stearate among other salts (Bourassa & Tardif, 2006).
Pharmacology
Norvasc drug is mainly administered orally, and shows a good ability of being absorbed by the body when taken through this means. The drug has an average bioavailability of about 60%. The half-life of the drug is approximately 30-50 hours, while the steady state blood plasma conditions are attained after a period of 7 days when it is administered on a daily basis. The long period can mainly be attributed to the pKa of 8.6. The metabolism of Amlodipine occurs within the liver through the aid of CYP3A4, where the nitrogen chain is oxidized while the ester is hydrolyzed. Elimination of the drug from the body generally occurs by means of renal action (Ebadi & Ebadi, 2008). Amlodipine can be readily attained as a generic drug. The costs of the drug in the developing nations is about $ 0.5 for a day’s dosage.
Administration
The dosage of the Norvasc varies with the conditions of the individual. For instance, Hypertension treatment usually involves the administration of 5 milligrams per day during the initial stages. The dosage may then be amplified by 2.5 milligrams for every 2 weeks. However, the medication should not be more than 10 milligrams per day at any given time. For the artery disease, the dosage may involve the administration of 5-10 milligrams daily during the beginning of the treatment process.
Amlodipine therapy can be administered in combination with other drugs. For example, atorvastatin may be additionally taken in scenarios in which the patient has high blood pressure. The drug works to inhibit any cardiovascular malfunction. Furthermore, it may be employed when the cholesterol amounts are too high. On the other hand, the Aliskiren medication may be used to supplement the action against blood pressure by working to inhibit the renin (Parati, Dolan, Ley & Schumacher, 2014).
There exist scenarios when Norvasc ought not to be used. For instance, these can include cases when the individuals have a cardiogenic shock condition. During this scenario, there is an inability of the heart to pump sufficient blood. Hence, the operations of the Amlodipine with further worsen the situation by hindering the movement of calcium ions into the cardiac region, which is needed for the heart to function.
Pharmacodynamics
The drug works by preventing the calcium ions from accessing the vascular and cardiac tissues, which leads to the prevention of the respective muscles to contract. The action greatly occurs in the cell membranes. The most inhibition however occurs in the tissue of the vascular muscles. As a result, this leads to both vasodilation and a lowered resistance of the vessels, hence leading to lowered pressures.
Norvasc causes vasodilation when administered to patients suffering from high blood pressure. As a result, there is not only a decrease in the supine but also in the standing pressures of the blood. However, the heart rate of the patient does not vary with the changes in the pressures. Furthermore, the catecholamine quantities in the blood do not change due to continuous dosing of the medication. However, when intravenously administered to patients as a result of acute conditions, the drug has shown a decrease in blood pressure. Furthermore, this is accompanied by rise in the heart rates of the patients suffering from a recurrent angina. Furthermore, longstanding administration of the drug through oral means has not been recorded to produce any changes in the heart rates, or any rise of the blood pressure. The subjects in the particular study were all characterized by normotensive angina. A daily administration of the medication over a relatively long period through the use of oral means has shown that its effects usually last for not less than 24 hours. The concentrations in the blood depends with the patients’ ages and the extent of pretreatment offered (Acosta, 2010).
Pharmacokinetics
Following the administration of the doses recommended for therapeutic purposes, the absorption of the Norvasc drug in an individual commences. The highest concentrations of the drug in the bloodstream occurs at any point within a 6 to12-hour window after the administration. The consequent availability of the absorbed drug has been determined to be anywhere around 64-90% depending on the individual and the dosage. The existence of food in the gut does not hinder the absorption of the drug (Frishman, Cheng-Lai & Newarskas, 2005). The kinetics associated with the use of the drug are not greatly affected by deficiency in the renal function. As a result, individuals suffering from the problem may be supplied with the normal dose. Older individuals having a deficiency in the ability of the liver to metabolize the drug will therefore show a reduced metabolism of Amlodipine. As a result, they will require a decreased initial dosage.
The amlodipine compound is greatly transformed into dormant metabolites through the function of the liver. Only a 10% composition of the original amount and 60% of the products of metabolism are discharged through urination. Studies have shown that of the total amount of the drug in the plasma, about 93% is combined to the proteins in individuals suffering from high blood pressure.
Manufacturing Procedure
The manufacturing process of the drug involves the use of the 2-Chlorobenzaldehyde compound, which is then made to react with a methyl acetoacetate compound. The product attained from the reaction is known as methyl 2-(2-chlorobenzylidene) acetoacetate. The product is then made to react with an enamine which is made through the combined reactions of another acetoacetate compound with an ammonium acetate compound. The reaction, which is conducted in the presence of ethanol, leads to the production of the required Amlodipine compound (Park, 2014).
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