Hypertension, calcium channel blockers

Hypertension Calcium channel blockers ACE inhibitors ARBs Diltiazem, verapamil inhibit CSA/TAC metabolism Dihydropyridines may potentiate CSA-gingival hyperplasia May exacerbate hyperkalemia monitor K+, SCr to assess for renal allograft vascular disease may be useful in posttranplant erythrocytosis (hematocrit greater than 55%)... 

Hypertension Calcium channel blockers Diltiazem, verapamil inhibit CSA/TAC metabolism Dihydropyridines may potentiate CSA-gingival hyperplasia... 

Calcium channel blockers reduce arterial blood pressure by decreasing calcium influx, resulting in a decrease in intracellular calcium (236,237). The arterial smooth muscle tone decreases, thereby decreasing total peripheral resistance. The increase in vascular resistance in hypertension is found to depend much on calcium influx. Calcium channel blockers reduce blood pressure at rest and during exercise. They decrease the transmembranous calcium influx or entry that lead to a net decrease of intracellular calcium and therefore the vascular tone falls, as does blood pressure. 

Calcium channel blockers normalize the blood pressure in about 80% of hypertensive patients older than 60 years of age, 50% of those between 40 and 60 years of age, and only 20% of patients under 40 years of age. Thus calcium channel blockers are best for patients who are elderly and have low PRA and mosdy ineffective in patients who have high PRA. This responsiveness profile is very similar to that of the diuretics. 

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... 

Procardia XL. Procardia XL extended-release capsules, marketed by Pfizer Labs Division of Pfizer, Inc., contain nifedipine [21829-25-4] a calcium channel blocker of mol wt 346.3. The extended release tablet is formulated as a once-a-day controlled release capsule for oral adrninistration dehvering either 30, 60, or 90 mg nifedipine. Procardia XL is indicated for use in the management of vasospastic angina, chronic stable angina, and hypertension (see Cardiovascularagents). 

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. 

ACE inhibitors - AT antagonists - Alpha blockers - Beta blockers Isolated syslolic hypertension (older patienls) - Diuretics preferred (generally Thiazides) - Long-acting dihydropyridine calcium channel blocker... 

Benzothiazepines belong to the three classes of calcium channel blockers which are important cardiovascular drugs in the management of angina pectoris and hypertension. A diastereoselective one-pot synthesis of the trans-and ds-3-hydroxy-2-(4-methoxyphenyl)-2,3-dihydro-l,5-benzothiazepin-4-one nucleus, a key intermediate in the preparation of the calcium channel blocker Diltiazem, was carried out under microwave irradiation in an open vessel (Scheme 25). Control of the diastereoselectivity was achieved by vary-... 

BP, blood pressure CCB, calcium channel blocker agent DBP, diastolic blood pressure SBP, systolic blood pressure. (Adapted from JNC 7 Modified from Saseen JJ, Carter BL. Hypertension. In DiPiro JT, Talbert RL, Yee GC, et al, (eds.) Pharmacotherapy A Pathophysiologic Approach. 6th ed. New York McGraw-Hill 2005 194, with permission.)... 

Patients with asymptomatic left ventricular systolic dysfunction and hypertension should be treated with P-blockers and ACE inhibitors. Those with heart failure secondary to left ventricular dysfunction and hypertension should be treated with drugs proven to also reduce the morbidity and mortality of heart failure, including P-blockers, ACE inhibitors, ARBs, aldosterone antagonists, and diuretics for symptom control as well as antihypertensive effect. In African-Americans with heart failure and left ventricular systolic dysfunction, combination therapy with nitrates and hydralazine not only affords a morbidity and mortality benefit, but may also be useful as antihypertensive therapy if needed.66 The dihydropyridine calcium channel blockers amlodipine or felodipine may also be used in patients with heart failure and left ventricular systolic dysfunction for uncontrolled blood pressure, although they have no effect on heart failure morbidity and mortality in these patients.49 For patients with heart failure and preserved ejection fraction, antihypertensive therapies that should be considered include P-blockers, ACE inhibitors, ARBs, calcium channel blockers (including nondihydropyridine agents), diuretics, and others as needed to control blood pressure.2,49... 

Patients with diabetes and hypertension should initially be treated with either P-blockers, ACE inhibitors, ARBs, diuretics, or calcium channel blockers. There is a general consensus that therapy focused on RAAS inhibition by ACE inhibitors or ARBs may be optimal if the patient has additional cardiovascular risk factors such as left ventricular hypertrophy or chronic kidney disease.2,3,59,67... 

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. 

Uncontrolled hypertension Valvular disorders function sympathomi meti cs) Offending medications (NSAIDs, COX-2 inhibitors, steroids, lithium, (i-blockers, calcium channel blockers, anti-arrhythmics, alcohol, thiazolidinediones)... 

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. 

Patients who had been prescribed calcium channel blockers for hypertension who are not receiving //-blockers and who do not have a contraindication should have the calcium channel blocker discontinued and a //-blocker initiated. 

The cure for preeclampsia is delivery of the fetus if the pregnancy is at term. Drug therapy for hypertension in preeclampsia includes methyldopa, labetalol, and calcium channel blockers. Magnesium sulfate is used to prevent eclampsia and to treat eclamptic seizures. 

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. 

Amlodipine and nifedipine are dihydropyridine calcium-channel blockers. Amlodipine differs from nifedipine in that it has a longer duration of action and can therefore be given once daily, unlike nifedipine. Both are indicated in hypertension and angina and tend to cause ankle oedema that does not respond to diuretic therapy. Neither amlodipine nor nifedipine are available as spray formulations. 

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