Multicenter comparison of the nifedipine gastrointestinal therapeutic system and long-acting propranolol in patients with mild to moderate systemic hypertension receiving diuretics. A preliminary experience

Long-acting nifedipine in the management of essential hypertension: a review for cardiologists

Calcium channel antagonists, specifically long-acting nifedipine formulations, play a crucial role in treating hypertension and angina. Originally used for angina, nifedipine has been widely employed as an antihypertensive medication for over 40 years. It offers rapid action and oral bioavailability with minimal maternal or fetal side effects, making it suitable for treating hypertensive crises during pregnancy. However, it can cause a sudden drop in blood pressure and tachycardia. Long-acting formulations, such as gastrointestinal therapeutic systems, gradually release nifedipine over 24 hours, mitigating these issues. This review aims to assess the clinical efficacy and safety of long-acting nifedipine formulations in managing essential hypertension, with a focus on improving blood pressure control and addressing challenges in uncontrolled and resistant hypertension. Furthermore, long-acting nifedipine provides therapeutic advantages beyond hypertension management, showing efficacy in treating comorbid conditions such as chronic kidney disease and diabetes. Global studies support its efficacy, suggesting that a shift toward the use of long-acting nifedipine can help address the global hypertension problem and enhance the quality of life for hypertensive patients.

Long-acting nifedipine in the management of the hypertensive patient

Hypertension is a global condition affecting billions worldwide. It is a significant contributor to cardiovascular events, cardiac death and kidney disease. A number of medication classes exist to aid healthcare providers and their patients in controlling hypertension. Nifedipine, a dihydropyridine calcium channel blocker, was once one of the most widely used medications for hypertension, but safety and tolerability concerns along with the introduction of new classes of antihypertensive medications and an increasing pool of data showing mortality benefit of other classes caused nifedipine to fall out of favor. More recently, long-acting formulations were developed and made available to clinicians. These newer formulations were designed to address many of the concerns raised by earlier formulations of nifedipine. Numerous clinical trials have been conducted comparing long-acting nifedipine to many of the more commonly prescribed antihypertensive medications. This review will address the pharmacology, pharmacokinetics and the available clinical trial data on long-acting nifedipine and summarize its role in the management of hypertension.

Nifedipine gastrointestinal therapeutic system (GITS). A review of its pharmacodynamic and pharmacokinetic properties and therapeutic efficacy in hypertension and angina pectoris

Nifedipine 'gastrointestinal therapeutic system' (GITS) is a recently developed formulation that slowly releases the drug into the intestinal tract over a 24-hour period. When administered once daily, it is of similar efficacy to sustained release formulations of felodipine, verapamil, and diltiazem and at least as effective as standard formulations of lisinopril and enalapril, and long-acting propranolol and atenolol in the treatment of patients with mild to moderate essential hypertension. Substitution of nifedipine GITS for conventional formulations of nifedipine, diltiazem or verapamil, maintained adequate control of anginal symptoms in patients with stable angina pectoris. Nifedipine GITS appears to maintain quality of life and is apparently better tolerated than those formulations of nifedipine which require 2 or 3 times daily administration in both elderly and younger patients. In addition, it has minimal effect on lipid and glucose metabolism and reverses left ventricular hypertrophy, and is thus suitable for treatment of the majority of patients with mild to moderate hypertension or angina pectoris.

Combination drug therapy with calcium-channel blockers in the treatment of systemic hypertension

Calcium-channel blockers have been shown to be both safe and effective for treatment of patients with systemic hypertension. These drugs reduce peripheral vascular resistance predominantly by the inhibition of transmembrane calcium ion fluxes in vascular smooth muscle, and by this mechanism can reduce elevated blood pressure. To maximize blood pressure lowering efficacy in patients, calcium-channel blockers have also been used in combination with other antihypertensive treatments that have included diuretics, beta-adrenergic blockers, and angiotensin-converting enzyme inhibitors.

Issues in contemporary drug delivery. Part VI: Advanced cardiac drug formulations

OBJECTIVE

To identify and discuss the clinical utility of new delivery systems and formulations of cardiac drugs.

DATA SOURCES

Studies describing or evaluating new drug delivery systems for cardiac drugs were identified through a MEDLINE literature search.

STUDY SELECTION

All studies describing or evaluating new delivery systems for cardiac drugs were reviewed.

DATA EXTRACTION

Data were abstracted and evaluated by each author independently.

DATA SYNTHESIS

The most common oral sustained-release formulations include the wax-matrix system, the gastrointestinal therapeutic system (GITS), and the spheroidal oral drug absorption system (SODAS). The wax-matrix delivery system is limited by the occurrence of "dose-dumping." In a low-pH setting, the wax-matrix formulation may dissolve too rapidly, liberating the entire dose in a short period of time. The clinical relevance of this phenomenon is unknown. The GITS and SODAS formulations are less likely to be affected by pH and food. Nitroglycerin is available by many routes of administration. The topical patch forms are convenient to use, but are associated with the development of tolerance. A buccal formulation incorporates a relatively short onset of effect with a three- or four-times-daily dosing regimen. Although tolerance is less of a problem with buccal nitroglycerin than with topical nitrates, this formulation is less convenient to use because of buccal irritation and interference with eating and talking. A new spray formulation of nitroglycerin offers longer shelf-life storage stability and an easier mode of administration. The spray canister is stable for three years compared with 12 weeks for an opened bottle of sublingual nitroglycerin tablets. Sublingual administration of oral cardiac drugs offers the potential for a more rapid onset of effects. Although nifedipine is often given sublingually, objective data indicate that it is not absorbed buccally but rather in the stomach. It appears that the chew-and-swallow route is most appropriate for nifedipine. Captopril is absorbed sublingually but its efficacy has not been demonstrated. Transdermal clonidine improves compliance and is associated with fewer adverse effects than oral clonidine. Transdermal formulations of beta-blockers are currently being evaluated.

CONCLUSIONS

Further advancements in the development of novel delivery systems for cardiac drugs are expected in the future.

The relationship of sodium balance and concomitant diuretic therapy to blood pressure response with calcium channel entry blockers

Marked heterogeneity exists in the response of blood pressure to specific antihypertensive agents. In general, a single therapeutic agent can be expected to provide an adequate blood pressure response in 40% to 60% of hypertensive patients. The addition of a second agent usually extends the response rate to over 85%. The addition of a diuretic to nondiuretic regimens often produces an additive blood pressure-lowering effect. However, calcium channel entry blockers (CCBs) may be an exception, as diuretics do not appear to improve these agents' efficacy. CCBs have a dual mechanism for blood pressure reduction. In addition to their vasodilatory actions, they also promote diuresis and natriuresis. These features account for the striking efficacy of these agents when used as monotherapy in hypertensive patients. Studies have shown that dietary sodium restriction does not appear to improve the efficacy of CCBs, nor is a high-salt diet predictive of a better therapeutic outcome. Recent studies also indicate that the addition of a diuretic to a CCB does not produce a significant or consistent additive antihypertensive effect. Because CCBs do not produce the typical responses of the renin-angiotensin-aldosterone (RAA) system to sodium/volume depletion, their diuretic and natriuretic effects do not result in the same adverse metabolic consequences as experienced with traditional diuretic therapy.

Sustained release nifedipine formulations. An appraisal of their current uses and prospective roles in the treatment of hypertension, ischaemic heart disease and peripheral vascular disorders

Nifedipine antagonises influx of calcium through cell membrane slow channels, and sustained release formulations of the calcium channel blocker have been shown to be effective in the treatment of mild to moderate hypertension and both stable and variant angina pectoris. Preliminary findings also indicate that these formulations are effective in the treatment of Raynaud's phenomenon and hypertension in pregnancy, and that they reduce the frequency of ischaemic episodes in some patients with silent myocardial ischaemia. The exact mechanism of action of nifedipine in all of these disorders has not been defined. However, its potent peripheral and coronary arterial dilator properties, together with improvements in oxygen supply/demand, are of particular importance. A major goal of sustained release therapy is to permit reductions in the frequency of nifedipine administration, preferably to once daily, and thus improve patient compliance. Two new once-daily formulations--the nifedipine gastrointestinal therapeutic system (GITS) and a fixed combination capsule comprising sustained release nifedipine 20 mg and atenolol 50 mg--have exhibited marked antihypertensive efficacy. The GITS preparation has also been used effectively in the treatment of stable angina pectoris, and both formulations appear to be well tolerated. Sustained release nifedipine formulations are generally better tolerated than their conventionally formulated counterparts, particularly with regard to reflex tachycardia. Adverse effects seem to be dose related, are mainly associated with the drug's potent vasodilatory action, and include headache, flushing and dizziness. Generally, these effects are mild to moderate in severity and transient, usually diminishing with continued treatment. Thus, sustained release nifedipine formulations are useful and established cardiovascular therapeutic agents which have demonstrable efficacy in various forms of angina, mild to moderate hypertension and Raynaud's phenomenon. Further, promising results shown by the nifedipine GITS formulation, with its advantage of once daily administration suggest that it is likely to become one of the preferred nifedipine formulations for the treatment of hypertension and the various forms of angina.

The nifedipine gastrointestinal therapeutic system in the treatment of hypertension

As the number of antihypertensive agents increases, the choice of optimal therapy becomes more difficult. Certainly, hemodynamic derangements caused by the disease state as well as therapy must be considered. Patient convenience and quality of life are also issues that must be addressed. Preliminary experience suggests that the gastrointestinal therapeutic system (GITS) push-pull osmotic pump formulation of nifedipine is safe and efficacious in the treatment of hypertension. In 1 study, nifedipine GITS was compared with sustained-release propranolol in patients with mild to moderate hypertension already receiving diuretics. Using a 2-week placebo run-in, double-blind study design, patients were randomly assigned to receive nifedipine GITS (n = 31) in doses of 30, 60 or 90 mg once daily, or sustained-release propranolol (n = 32) in doses of 80, 160 or 240 mg once daily. Previous diuretic therapy was continued. Sitting and 5-minute standing blood pressure and heart rate measurements were obtained 24 hours after dosing. At the end point of treatment, both nifedipine GITS and sustained-release propranolol reduced blood pressure compared with placebo (p less than 0.001) in the sitting and standing positions. Nifedipine GITS was more effective than sustained-release propranolol in reducing standing (p less than 0.005) and sitting (p less than 0.001) systolic blood pressure and sitting diastolic blood pressure (p less than 0.02). Sustained-release propranolol caused a greater reduction in standing (p less than 0.001) and sitting (p less than 0.0006) resting heart rate than nifedipine GITS. Both drugs were well tolerated.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium metabolism, calcium-channel blocking agents, and hypertension management

Increasing evidence has suggested that a disturbance of cellular calcium metabolism may have a role in initiating and maintaining elevated systemic vascular resistance in essential hypertension. Controversy exists over whether calcium can alleviate or exacerbate the hypertensive process, and diversity of calcium metabolism in hypertensive patients has been proposed. Calcium-channel blocking agents are potent vasodilators capable of correcting the elevated systemic vascular resistance. Clinical studies have shown that these drugs have antihypertensive efficacy comparable to established agents. The elderly, blacks, and patients with low renin activity respond well to calcium-channel blockers. These drugs may also offer potential advantages over established antihypertensive agents in patients with other coexisting diseases. Sustained release formulations have been developed, and initial experience with long-term efficacy and tolerability is encouraging. The calcium-channel blockers may become first-line therapy for treatment of hypertension in selected patients.

Calcium channel blockers in systemic hypertension

Alterations in transmembrane flux of calcium ions may be playing a role in the pathophysiology of systemic hypertension. Calcium channel blockers have been shown to be effective antihypertensive drugs with excellent safety profiles. They are efficacious in the long term treatment of systemic hypertension in all population subgroups, and have special applicability for treating patients with hypertensive urgencies and individuals with concomitant diseases such as angina pectoris and arrhythmias.