Calcium channel blocker hypertension treatment

CALCIUM-CHANNEL BLOCKERS FORTHE TREATMENT OF HYPERTENSION... 

Calcium channel blockers cause more pronounced lowering of blood pressure in hypertensive patients than in normotensive individuals. Generally, all calcium channel blockers cause an immediate increase in PRA during acute treatment in patients having hypertension but PRA is normalized during chronic treatment despite the sustained decrease in blood pressure. These agents also do not generally produce sodium and water retention, unlike the conventional vasodilators. This is because they produce diuretic effects by direct actions on the kidney. 

The sales of oral diuretics are declining, and are forecast to continue their decline in constant dollars during the 1990s (119,120). Several possible explanations can be offered for these trends. The patents of market leaders are expiring, lea ding to the introduction of generic brands at ca 40% below the cost of the branded market leaders physicians are switching to newer treatments for hypertension, eg, calcium channel blockers and... 

The so-called calcium channel blockers constitute a class of cardiovascular agents that have gained prominence in the past few years. These drugs, which obtund contraction of arterial vessels by preventing the movement of calcium ions needed for those contractions, have proved especially useful in the treatment of angina and hypertension. Dihydropyridines such as nifedipine (30) are par-... 

In the treatment of hypertension, ACE inhibitors are as effective as diuretics, (3-adrenoceptor antagonists, or calcium channel blockers in lowering blood pressure. However, increased survival rates have only been demonstrated for diuretics and (3-adrenoceptor antagonists. ACE inhibitors are approved for monotherapy as well as for combinational regimes. ACE inhibitors are the dtugs of choice for the treatment of hypertension with renal diseases, particularly diabetic nephropathy, because they prevent the progression of renal failure and improve proteinuria more efficiently than the other diugs. 

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 2002 288(23) =2981-2997. 

Baroletti SA, Gabardi S, Magee CC, Milford EL. Calcium channel blockers as the treatment of choice for hypertension in renal transplant recipients Fact or fiction. Pharmacotherapy 2003 23(6) 788-801. 

Nifedipine is a calcium-channel blocker of the dihydropyridine group. It relaxes smooth muscle and dilates both coronary and peripheral arteries by interfering with the inward displacement of calcium-channel ions through the active cell membrane. Unlike verapamil, nifedipine can be given with beta-blockers. Long-acting formulations of nifedipine are preferred in the long-term treatment of hypertension. 

Calcium-channel blockers such as amlodipine can be used in patients receiving angiotensin-receptor blockers such as valsartan for the treatment of hypertension and angina. Side-effects common to both drugs include dizziness and hypotension. 

A 47-year-old man recently received a heart transplant and is being discharged home with oral medications, including cyclosporine. The physician also prescribed diltiazem, a calcium channel blocker used for the treatment of hypertension. Since he did not have hypertension, the patient wondered why this additional drug was being prescribed. 

If a patient s blood pressure is greatly increased, pharmacological treatment should be instituted. Treatments for MAOI-induced hypertension include administration of the calcium channel blocker nifedipine and use of drugs with a-adrenergic-blocking properties, such as phentolamine (5 mg intravenous). Because treatment with phentolamine may be associated with cardiac arrhythmias or severe hypotension, this approach should be carried out only in an emergency department setting. 

Because adrenergic agents such as P-blockers find such extensive use as hypotensive drugs, the etiology and drug combination treatment of hypertension are of considerable interest. A discussion in any detail of this complex and confusing field goes beyond the scope of this book, however. Other aspects of hypertension will be discussed in connection with the renin and vasopressin systems and calcium channel blockers. 

Calcium channel blockers are considered the drug of first choice for the treatment of posttransplant I hypertension since they increase renal blood flow. Nifedipine, isradipine and amlopidine show little interac-l tion with cyclosporine-A. Diltiazem and verapamil elevate cyclosporine-A levels. I... 

Basile J. The role of existing and newer calcium channel blockers in the treatment of hypertension. J Clin Hypertens. 2004 6 621-629. 

Black HR. Calcium channel blockers in the treatment of hypertension and prevention of cardiovascular disease results from major clinical trials. Clin Cornerstone. 2004 6 53-66. 

In addition to their antianginal (see Chapter 12 Vasodilators the Treatment of Angina Pectoris) and antiarrhythmic effects (see Chapter 14 Agents Used in Cardiac Arrhythmias), calcium channel blockers also dilate peripheral arterioles and reduce blood pressure. The mechanism of action in hypertension (and, in part, in angina) is inhibition of calcium influx into arterial smooth muscle cells. 

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