Calcium Channel Blockers in Hypertension - Article Example

Calcium channel blockerS in hypertension BY [Name of the organization] [Author’s name] [Date of fulfillment] Introduction Hypertension remains a major modifiable risk factor for cardiovascular disease (CVD) despite important advances in our understanding of its pathophysiology and the availability of effective treatment strategies. High blood pressure (BP) increases the risk of CVD for millions of people worldwide, and evidence suggests the problem is attaining alarming proportions day by day. Hypertension is a quantitative trait that is highly variableand there is a strong positive and continuous correlation between BP and the risk of CVD Essential, primary, general or idiopathic hypertension is defined as high BP in which secondary causes such as renovascular disease, renal failure, pheochromocytoma, aldosteronism, or other causes of secondary hypertension or mendelian forms (monogenic) are not present. Essential hypertension accounts for 95% of all cases of hypertension. Essential hypertension is a heterogeneous disorder, with different patients having different causal factors that lead to high BP. Although it has frequently been indicated that the causes of essential hypertension are not known, this is only partially true because we have little information on genetic variations or genes that are overexpressed or underexpressed as well as the intermediary phenotypes that they regulate to cause high BP.4 A number of factors increase BP, including (1) obesity, (2) insulin resistance, (3) high alcohol intake, (4) high salt intake (in salt-sensitive patients), (5) aging and perhaps (6) sedentary lifestyle, (7) stress, (8) low potassium intake, and (9) low calcium intake. Furthermore, many of these factors are additive, such as obesity and alcohol intake. Calcium channel blockers or as popularly known as CCBs have been used in the cases that are related to various forms of hypertension, specifically pulmonary arterial hypertension or PAH. AM Nackoneczie, AJ Giannini, SM Melemis, J Ventresco, M Condon in their ‘Magnesium oxide augmentation of verapamil maintenance therapy in mania’ have declared that this is a practice that has been followed for more than last 25 years. However even after being such a popular practice the Calcium channel blockers have never been evaluated in a randomized trial in PAH patients. There are specifically 5 drugs approved for the treatment of PAH, even then the application of CCBs as a therapeutic option for patients with PAH is a common practice. Treatments with CCBs are very effective, but as a matter of fact these drugs only benefit a small minority of patients, yet studies shows that it is more effective in patients with idiopathic PAH (IPAH). Usability of CCB The main functionality of calcium channel blockers lays in the action to decrease the blood pressure in the patient. Its usability is very high as it is used in individuals with hypertension on specific grounds. There are many kinds of drugs in support of Calcium channel blockers. These are most commonly available as nifedipine (Adalat), amlodipine (Norvasc), diltiazem, verapamil. According to the specialised study made by ALLHAT (2002) the use of CCBs are more preffered by the physicians and the specialists because they are better in cost-effectiveness and are slightly better in delivering rapid outcomes for the thiazide diuretic chlortalidone. The calcium channel blockers (CCBs) are used as one of several classes of medications for exclusive treatment of hypertension (high blood pressure) in an individual. The CCBs work is very effective. Koenig W. in his ‘Efficacy and tolerability of felodipine and amlodipine in the treatment of mild to moderate hypertension’ declares that it functions towards the lowering of blood pressure by interfering with the normal role of calcium in the heart and blood vessels. The process acts towards the simultaneous blocking calcium's entry into the heart muscle and blood vessels. CCBs dilate the blood vessels and cause the contraction of the heart to slow down than its increasing speed. This is how there is the control over the blood pressure and eventually it gets lowered. Cardizem CD, Morrisville, (2001) says that the usability and the researchers that have undertaken in past few decades have clarified that CCBs have been used for the treatment of pulmonary arterial hypertension with all protective measures. Any kind of CCB treatment for the purpose of pulmonary hypertension comes from animal data as well as case reports. CCBs for treatment of pulmonary hypertension have been used in much wider sense than ever. It started after Rich and colleagues published their experience using CCBs in 1992. As per their speculations and affirmation of Cardizem SR, in Cardizem. Physicians Desk (1999), the use of diltiazem for patients who had a heart rate higher than 100 beats/minute and nifedipine for patients with a heart rate below 100 beats/minute are very appropriate and effective for rapid recoveries. Patients with cardiac index below 2.0 L/minute/m2 get very limited application of CCBs. The reason is that there are the concerns of negative inotrop effects of CCBs with these kinds of patients. The usability of Verapamil is limited as it has significant cardiodepressive properties and is specifically avoided in patients with pulmonary hypertension. Patients who cannot tolerate diltiazem or nifedipine, then amlodipine or other long-acting dihydropyridines, the application of it is very much preferred. Dilacor XR, from Physicians Desk (2000) CCBs need to be utilised as per the situational demand of the patient’s blood pressure and the heart condition. It is very much limited to the patients who have a positive acute vasoreactivity to a vasodilator challenge. Test like epoprostenol, nitric oxide, and adenosine are enough to make all kinds of clarifications. Haggert BE, Fagan TC, Liss C (1994) find that under all circumstances the use of CCBs is done very peculiarly for pulmonary hypertension and for the purpose of its contraindication. The most noteworthy thing is that the treatment should be in cases where patients have got blood pressure control up to 12-15 mm Hg or on the contrary, patients with a low output state, doesn’t required an acute vasodilator challenge. The reason is simple. Since there is an increase in CCB dose the circumstances might get deleterious. This is something very much adverse of CCB and thus there is the need for the discontinuing conditioning of the CCB and substituting another agent in its place. Weinberger HD, Horwitz LD, Clegg L. (1997) specifies that patients who do not have hemodynamic compromise, there again come in the doubt whether CCB is really worth applicable. It is however very difficult to know without a pre-CCB RHC. This leads to the instance when there is a severe need for an acute vasodilator challenge, in order to assess for further vasoreactivity2. If there continues to be a regular decrease in the mean pulmonary arterial pressure, that is mPAP to a level < 40 mm Hg, there might be a consequence that might facilitate the decision to "push" the dose of the CCB little higher than the average. However some kinds of reliable oral agents are proffered more by most of the physicians. There is still a kind of uncertainty in the effectiveness of the CCB therapy. These are more vital for the patient who remains symptomatic. There are many kinds of calcium channel blockers that are found to be very much active in slowing down the conduction of electrical activity within the heart. The act takes place by blocking the calcium channel during the plateau phase of the action that is there in a state with feasible potentiality of the heart, which is called negative dromotropic effect. The heart rate gets lowered down and there is every possibility of the negative chronotropic or the heart blocks effect of calcium channel blockers. The negative chronotropic are very active in creating an effective ground for calcium channel blockers that becomes commonly used class of agents in individuals with atrial fibrillation or flutter in who control of the heart rate is not that easy. Dosing and Administration The specification of dosing and administration is very important in the application of CCBs. There are some products like those of nifedipine, verapamil, diltiazem, nicardipine that can be dosed up to three or four times daily to a patient. In some cases there can be a sustained release formulations of nicardipine SR, isradipine, verapamil SR are done. These are typically dosed twice daily. In cases with extended-release formulations there is the application of nifedipine, nisoldipine, amlodipine, felodipine, isradipine, extended-release verapamil can often be dosed once daily. The practice of once daily dosing is recommended when CCBs are used to treat individuals with high blood pressure and angina that is chest pain. The reason as has been forwarded is that it might cause abrupt changes in blood pressure. As a result heart rate may occur if a dose is missed of a drug taken two or three times daily. conclusion Like any other drugs CCBs are also having all kinds of affects and effects in dealing with hypertension. There are many kinds of researches and studies that have compared the CCBs to each other and to drugs in other drug classes for the treatment of hypertension. It has been found that all CCBs are effective in lowering blood pressure and as effective as drugs in other drug classes in lowering blood pressure. Especially the combinations as are available in nicardipine are more effective and are used to treat severe hypertension. CCBs are found to be well tolerated with mild side effects by the patients. They equally bear higher incidence of side effects than the others3. This is very much common with the incidences initiated by verapamil that brings in more constipation than the other CCBs. The affects like swelling of the ankles and feet has been associated with higher doses of dihydropyridine CCBs. This however doesn’t occur with diltiazem and verapamil. The affects are also there is the dosages are not well maintained. In case of excessive growth of the gums that is gingival hyperplasia has been most commonly tracked with diltiazem and nifedipine. In spite of all these CCBs are still practiced with proper medical speculations for effective results. References AM Nackoneczie, AJ Giannini, SM Melemis, J Ventresco, M Condon. Magnesium oxide augmentation of verapamil maintenance therapy in mania, Psychiatric Researxh. 93:83-86, 2000. ALLHAT Officers and Coordinators for the ALLHAT Collaborative Research Group (Dec 18 2002). "Major outcomes in high-risk hypertensive patients randomized to angiotensin-converting enzyme inhibitor or calcium channel blocker vs diuretic: The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)". JAMA 288 (23): 2981–97. doi:10.1001/jama.288.23.2981. PMID 12479763 Cardizem CD, Morrisville, NC: Biovail Pharmaceuticals, Inc.; August 2001. Cardizem SR, in Cardizem. Physicians Desk , Reference. 53rd Ed. Montvale, NJ: Medical Economics Company, Inc. 1314-1316, 1316-1318. 1999 Conlin PR, Williams GH. Use of calcium channel blockers in hypertension. Advanc Intern Med.; 43:533-562. 1998 Dilacor XR, from Physicians Desk Reference. 54th Ed. Montvale, NJ: Medical Economics Company, Inc. 3172-3174. 2000 Domenic A. Sica, J Clin Hypertens 3(5):322-327, 2001. H.A. Bradley, C.S. Wiysonge, J.A. Volmink, B.M. Mayosi, L.H. Opie. How strong is the evidence for use of beta-blockers as first-line therapy for hypertension?. Systematic review and meta-analysis. J Hypertens, 24: 2006; 2131-2141 Haggert BE, Fagan TC, Liss C, ‘Efficacy and tolerability of extended-release felodipine and extended-release nifedipine in patients with mild-to-moderate essential hypertension’, Clin Ther. 16:634-646, 1994. Koenig W. ‘Efficacy and tolerability of felodipine and amlodipine in the treatment of mild to moderate hypertension’; Drug Investigation. 1993;5:200-205. Larochelle P, Leenan FHH, Wilson TW, et al. Patterns of compliance with once versus twice daily antihypertensive drug therapy in primary care: a randomized clinical trial using electronic monitoring. Can J Cardiol. 13:914-920; 1997 Neil Osterweil, What Your Patients Are Reading: ACE Inhibitor and Calcium-Channel Blocker Are Best Against Hypertension, INFORMATION FROM INDUSTRY, April 3, 2008, Medscape Parker RB, Johnson JA, Patterson JH. Heart Failure. In DiPiro JT, Talbert RL, Yee GC, et al, eds. Pharmacotherapy: A Pathophysiologic Approach. 6th ed. New York: McGraw-Hill; p. 185-217. 2005. Watchful Waiting May Beat Papanicolaou Test in HPV-Positive Women, Journal of the National Cancer Institute, April 2, 2008, WebMD Weinberger HD, Horwitz LD, Clegg L. ‘Comparison of amlodipine and long-acting diltiazem in the treatment of mild or moderate hypertension’, Am J Hypertens. 10:1263-1269, 1997. Read More