Nifedipine, hypertension, angina treatment

Nifedipine Adalat Bayer U.K. (1) treatment and prophylaxis of angina pectoris (2) treatment of hypertension (3) treatment of Raynaud s phenomenon... 

Nifedipine (Table 3) is a potent vasodilator that selectively dilates resistance vessels and has fewer effects on venous vessels. It does not cause reflex tachycardia during chronic therapy. Nifedipine is one of the first-line choices for black or elderly patients and patients having concomitant angina pectoris, diabetes, or peripheral vascular diseases. Nifedipine, sublingually, is also suitable for the treatment of hypertensive emergencies. Nifedipine does not impair sexual function or worsen blood Hpid profile. The side effects are flushing, headache, and dizziness. 

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-... 

Step, aldol condensation to form the benzylidene derivative (12-3). Conjugate addition of a second mole of acetoacetate would then afford the 1,5-diketone (12-4). Reaction of the carbonyl groups with ammonia will lead to the formation of the dihydropyridine ring. Alternatively, acetoacetate may go on to form the imine (12-5) reaction of this with the aldol product (13-3) will give the same dihydropyridine. The product, nifedipine (12-6) [13], has been used extensively for the treatment of angina and hypertension. 

Nifedipine is a dihydropyridine calcium channel modulator, often used in the treatment of hypertension and angina. CYP3A4, with a minor contribution from CYP3A5, is the principal enzyme involved in the metabolism of nifedipine (81). Smith et al. examined the effect of St. John s wort (900mg/day... 

The calcium ion antagonists nifedipine 21829-25A] (62), verapamil [52-55-9] (63), and flunarizine [52468-60-7] (64) exhibit antitussive effects in a dose-dependent manner in guinea pigs (91). Pretreatment with a subthreshold dose of nifedipine also markedly increased the antitussive effects of morphine, dihydrocodeine, and dextromethorphan. However, none of the calcium ion antagonists are used clinically as antitussive agents. They are used in the treatment of angina and hypertension (see Cardiovascularagents). 

Mibefradil is a tetralol derivative developed as a unique CCB. Its efficacy as an antihypertensive was demonstrated in phase III trials, where doses of 50 to 100 mg were compared to other CCBs (nifedipine SR, diltiazem CD, nifedipine GITS, amlodipine). Mibefradil was shown to be equally effective as or more effective than nifedipine SR, diltiazem CD, nifedipine GITS, or amlodipine in reducing blood pressure in mild to moderate hypertension. Average reductions of diastolic blood pressure of as much as 15 mmHg were seen with the 100-mg dose. It was also found to be effective in the treatment of chronic stable angina. Thus, it was indicated for use in hypertension and stable angina at doses of 50 or 100 mg once daily (15). 

Nifedipine (Fig. 7.1) is the lead compound which was first introduced for the treatment of coronary angina. However, its use in the treatment of hypertension was blunted by a short plasma half-life (in the range of 1.5-2 h) this led to the need for multiple daily administration, and consequently blood pressure control and patient compliance were not fully achieved. However, slow-release formulations - for example, the once-daily Nifedipine Oros - made possible the wide use of nifedipine in cardiovascular therapy. 

In the past, the difficulties presented in the administration of drugs in the treatment of hypertensive emergencies were largely overcome with the use of nifedipine administered sublingually. The onset of action was rapid, and the drug was also used sublingually for the treatment of acute attacks of angina pectoris. Presently, two types of formulation of nifedipine are available, both intended primarily for peroral administration. The sustained-release formulation is... 

Nifedipine ( Adalat, Bayer 10A0)(20), used for the treatment of angina, 87 is a powerful peripheral vasodilator and has hypotensive properties in man.88 A dose of 30mg sublingually lowered blood pressure substantially in 1A essential hypertensives for more than k hrs. with a rise in heart rate and plasma renin activity. Nifedipine interferes with the transmembrane calcium flux causing a reduction in vascular smooth muscle tone.87)89 The conformational requirement for dopamine induced renal... 

Procardia XL (nifedipine) extended-release tablet for the treatment of angina and hypertension. 

There are approximately a dozen calcium channel antagonists marketed in the United States for the treatment of hypertension, certain dysrhythmias, and some forms of angina (see Chaps. 13,15, and 17). The calcium channel blockers are classified by their chemical structure as phenylalkylamines (e.g., verapamil), benzothiapines (e.g., diltiazem), and dihydropyridines (e.g., amlodipine, felodipine, nicardipine, and nifedipine). Several of these agents, namely, diltiazem, nicardipine, nifedipine, and verapamil, are formulated as sustained-release oral dosage forms or have a slow onset of action and longer half-life (e.g., amlodipine " ), allowing once-daily administration. 

Calcium antagonists (Figure 4.3) are agents which block the flow of calcium ions into cardiac and vascular smooth muscle when they are stimulated to contract. They have value as vasodilators for use in hypertension and also reduce blood flow resistance and cardiac workload in the treatment of angina. Verapamil (Knoll Pfizer, 1967) is also used as an antiarrhythmic because of its effects on ion channels in the heart s electrical conduction system. Nifedipine (Bayer, 1977) is among the world s top 25 drugs and is the forerunner of several agents of the dihydropyridine class. 

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