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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of intravenous administration of a new calcium antagonist, felodipine, were studied in healthy subjects and hypertensive patients. Felodipine infused at a rate of 0.01 mg/min in 10 normotensive volunteers caused gradual haemodynamic and hormonal changes compatible with a direct vasodilatory mechanism of action; it also had a diuretic and natriuretic effect. When infused at a mean dose of 0.02 mg/kg bodyweight over 20 to 120 minutes in 7 patients with a hypertensive emergency, felodipine caused a rapid reduction in blood pressure with a maximal fall in mean arterial pressure of 30.4 +/- 7.3% (mean +/- 1 SD) in 30 minutes. No serious side effects were observed. The haemodynamic effectiveness of an infusion rate of 0.01 mg/min was confirmed in a pilot study of 5 patients with refractory hypertension. On the basis of these findings, a schedule for the treatment of acute hypertension with intravenous felodipine is proposed.
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PMID:Haemodynamic effects of intravenous felodipine in normotensive and hypertensive subjects. 398 41

Felodipine (4(2,3-dichlorophenyl)-1,4-dihydro-2, 6-dimethyl-3-ethoxycarbonyl-5-methoxycarbonyl pyridine)), a selective vasodilating anti-hypertensive drug, was used in the treatment of spontaneously hypertensive rats (SHRs) and age-matched Wistar-Kyoto rats (WKYs) from age 6 to 14 weeks, ie during the time of high blood pressure development in SHRs. The effect of treatment on heart weight and on mesenteric resistance vessels (i.d. ca 170 microns) characteristics was investigated. In a first study, two oral doses of felodipine were added to the diet of SHRs, in concentrations of either 0.5 or 1.5 mg X g-1 rat food. Both treatments lowered mean arterial pressure by about 19% (p less than 0.001). In a second study, the lower dose of felodipine (0.5 mg . g-1 rat food) was therefore used to treat both SHRs and WKYs. Treatment did not interfere with weight or food intake of either SHRs or WKYs but increased average weekly water intake significantly. In neither strain was the pulse rate or, surprisingly, heart/body weight ratio affected by treatment. Furthermore, mesenteric resistance vessel morphology and mechanics were not affected by the blood pressure reduction. The noradrenaline and calcium sensitivity of mesenteric resistance vessels from treated rats was greater (p less than 0.001) than those from control rats. These findings indicate that blood pressure reduction with felodipine does not affect cardiovascular structure in young SHRs.
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PMID:Lack of effect of anti-hypertensive treatment with felodipine on cardiovascular structure of young spontaneously hypertensive rats. 404 20

The haemodynamic effects of a new vasodilating drug, felodipine, were studied in eight, healthy, male subjects, aged 22-31 years. The drug was given as an oral solution in the dose of 0.15 mg/kg. Thirty-five minutes later further dose of 0.15 mg/kg was administered. Felodipine induced a pronounced decrease in diastolic blood pressure (maximal effect 15 +/- 4 mm Hg) and in the systemic vascular resistance. Cardiac output increased (maximum by 4.2 +/- 0.31/min), due to an increase both in the stroke volume and the heart rate. The maximal increase in the stroke volume (measured from echo cardiograms) and the heart rate were 33 +/- 5 ml and 23 +/- 3 beats/min, respectively. Felodipine caused a significant decrease in the pre-ejection period (23 +/- 3 ms) and an increase in the left ventricular ejection time (29 +/- 3 ms). The quotient PEP/LVET fell from 0.36 +/- 0.01 to 0.28 +/- 0.01. Significant activity of felodipine could be recorded at a plasma level of about 15 nmol/l. When the maximal haemodynamic effects were recorded the plasma level was about 40 nmol/l. After a cumulative dose of 0.30 mg/kg, there was a twofold variation in the maximal plasma level (from 31 to 61 nmol/l). The results of the present investigation are in agreement with previous haemodynamic studies in animals. It would appear that felodipine is a potent arteriolar vasodilator and it might well be of considerable value in the management of patients with hypertension or congestive cardiac failure.
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PMID:Haemodynamic effects of a new vasodilator drug, felodipine, in healthy subjects. 683 1

Today calcium antagonists (Ca-antagonists) are widely used agents in the management of various diseases of the circulatory system. More than 20 years ago the Ca-antagonists of the so-called 1st generation (Verapamil, Diltiazem, Nifedipine) were introduced for treatment of angina pectoris and later of essential hypertension. In the last decade an increasing number of agents structurally related to dihydropyridines were developed for the treatment of hypertension and/or coronary heart disease or cerebral disorders; the main target was to reduce side effects and to guarantee once or at least twice daily administration. Therefore the Ca-antagonists of the so-called 2nd generation (e.g. Amlodipine, Felodipine, Isradipine, Nitrendipine, Nicardipine, Nimodipine, Nisoldipine) tend to longer elimination-half-lives; Amlodipin is an exception with an elimination-half-life of 30 hours on the average. Apart from elimination rates, however, the biopharmaceutical and pharmacokinetic characteristics of all Ca-antagonists are similar: they are highly cleared drugs and are relatively highly protein bound. As they are subject to significant hepatic first-pass-metabolism old age and hepatic disease will increase their plasma-concentrations. Renal impairment affects little their pharmacokinetics since the fraction eliminated unchanged by the kidneys is small. For most agents, plasma-concentration-response relationships have been described. With exception of nicardipine a linear pharmacokinetic in all Ca-antagonists was demonstrated. Drugs and food affecting hepatic blood flow and drug metabolising capacity have predictable interaction potential. With regard to the acute pharmacodynamic effects the Ca-antagonists show similar qualitative effects, though there are quantitative differences. Orally administered dihydropyridine-derivatives induce acute hypotensive effects, whereas the other compounds show clinically relevant hypotensive effects only when administered chronically per os or less pronounced when given as intravenous infusion.
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PMID:[Principles of the pharmacokinetics and pharmacodynamics of calcium antagonists]. 813 31

Two hundred eighty-six patients with mild to moderate hypertension who had untreated diastolic blood pressure while seated of 95 to 115 mm Hg were randomized to receive placebo or once-daily doses of 2.5, 5, or 10 mg of the dihydropyridine calcium channel blocker felodipine extended release (ER). Blood pressure was measured 24 hours after dosing (at trough). Mean reductions in diastolic blood pressure after 8 weeks of double-blind treatment were significantly greater in each of the ER felodipine treatment groups (2.5, 5, and 10 mg ER felodipine: -7.8, -9.5, and -11.3 mm Hg, respectively) than in the placebo group (-5.3 mm Hg). The effect was dose dependent for both diastolic and systolic blood pressure. Moreover, much of the peak antihypertensive effect was still present at trough, confirming the 24-hour efficacy of the drug. Felodipine was well tolerated.
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PMID:Extended-release felodipine in patients with mild to moderate hypertension. Felodipine ER Dose-Response Study Group. 814 99

In a double-blind cross-over study, the arterial changes produced by hydrochlorothiazide were compared with those observed after the calcium antagonist felodipine in 16 patients with mild to moderate systemic hypertension. Diameter changes at the site of the common carotid and brachial arteries were investigated using pulsed Doppler velocimetry, and pulse-wave velocities of the aortic, brachial and femorotibial areas were measured using standard noninvasive techniques. Whereas hydrochlorothiazide and felodipine similarly decreased blood pressure, hydrochlorothiazide did not change pulse-wave velocity, and the diameters of the brachial and common carotid arteries. Felodipine significantly decreased pulse-wave velocity, and increased brachial arterial diameter and compliance, with no change in carotid arterial diameter. Evidence was found that although felodipine had specific effects on the arterial system of hypertensive subjects, hydrochlorothiazide did not produce any sizable arterial change. These differential effects may influence specifically the heart afterload, with important consequences for diuretics that are known to cause minimal changes in cardiac structure and function.
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PMID:Comparison of effects of felodipine versus hydrochlorothiazide on arterial diameter and pulse-wave velocity in essential hypertension. 821 11

Felodipine 4-(2,3-dichlorophenyl)-1,4-dihydropyridine-2,6-dimethyl-3,5- dicarboxylic 3-ethyl ester and 5-methyl ester, CAS 72509-76-3) is a new selective calcium antagonist for use in the management of hypertension or other cardiovascular disease, which requires reduction of peripheral vascular resistance. A combined 6- and 12-month study in dogs has been performed as a part of the preclinical safety program. 30 dogs, 5 males and 5 females per group, were treated with felodipine for 12 months. Additional 18 dogs, 3 males and 3 females per group, were interim-sacrificed after 6-month treatment. The dose levels were 2 x 0.38, 2 x 1.2 and 2 x 2.3 mg/kg daily. Initially, 2 x 3.8 mg/kg/d was used as a high dose. At this dose level 2 animals died preterminally after 4 days of dosing. They were replaced and the high dose level was reduced. Two similar control groups were given a placebo formulation for 12 and 6 months, respectively. All animals were treated b.i.d. using a 4-h time interval. Mucosal hyperemia and tachycardia, as an expression of the vasodilating properties of felodipine, were observed in a somewhat variable but dose-related manner. Noninflammatory gingival hyperplasia, similar to that after treatment with phenytoin and the calcium antagonist nifedipine, occurred with a propensity for the males after 12 months of treatment. Slight-degree gingival hyperplasia was also noted after 6 months of treatment. This change occurred dose- and time related in the medium and high dose groups but was absent in the low dose group.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:General toxicity of the new calcium antagonist felodipine in dogs. 836 3

Twenty patients with mild to moderate hypertension took part in this study consisting of a two-week placebo treatment period, followed by treatment with an extended-release calcium channel blocker, felodipine-ER (5 to 20 mg once daily) for 12 weeks. The study evaluated the effects of felodipine-ER on blood pressure, platelet function and rheological properties in hypertension. Felodipine-ER significantly reduced systolic and diastolic blood pressure without changing heart rate. There was a significant decrease in adenosine diphosphate-induced platelet aggregation and platelet intracellular calcium concentration, but no significant change in plasma thromboxane B2 (TXB2), 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and platelet cyclic 3'5'-adenosine monophosphate concentrations. Adverse effects on biochemical and rheological properties were not found. In conclusion, felodipine-ER is an effective and metabolically safe antihypertensive drug. It reduces platelet aggregability and intracellular free calcium concentration without altering the production of TXB2 and 6-keto-PGF1 alpha.
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PMID:Effect of felodipine-ER on blood pressure, platelet function, and rheological properties in hypertension. 839 93

Coexisting medical conditions often complicate the selection of antihypertensive drugs. Felodipine, a new vascular-selective calcium antagonist with demonstrated antihypertensive efficacy, has not been found to alter lipid profiles in hypertensive patients. Studies in additional patient populations have yielded insights into the effects of the drug on other diseases that may coexist with hypertension. In individuals with stable angina pectoris or congestive heart failure, acute administration of felodipine reduces systemic vascular resistance and increases cardiac output and total coronary blood flow; myocardial contractility is not depressed at doses that produce a clinically significant reduction in vascular resistance. In patients with coronary stenoses, the drug increases vessel diameter in the vicinity of obstructive lesions. Single-dose and long-term studies in patients with exertional angina have found that felodipine reduces anginal frequency and improves exercise tolerance. In patients with congestive heart failure, chronic dosing with felodipine produces a persistent reduction in vascular resistance and an increase in cardiac output, both at rest and during exercise. Symptomatic improvement and increased exercise tolerance have been noted in some studies. In patients with Raynaud's phenomenon, felodipine has been associated with a dose-dependent improvement in symptomatology. Among individuals with exercise-induced bronchospasm, the drug has no effect on resting bronchial tone and may exert some positive effects during exercise. In hypertensive patients with Type II diabetes, felodipine has not been found to raise glucose levels significantly. The data obtained thus far suggest that felodipine is safe for use in hypertensive patients with a variety of concomitant diseases.
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PMID:Treatment of hypertension with felodipine in patients with concomitant diseases. 845 9

The chemistry, pharmacology, pharmacokinetics, clinical uses, adverse effects, and dosage of felodipine and isradipine are reviewed. Felodipine and isradipine are new calcium-channel-blocking agents with FDA-approved labeling for use in the treatment of essential hypertension. Both agents are members of the dihydropyridine class of calcium antagonists, which also includes nifedipine and nicardipine. Like those agents, felodipine and isradipine affect blood pressure by producing peripheral vasodilation. Felodipine and isradipine undergo extensive first-pass metabolism; their bioavailabilities are approximately 15% and 17%, respectively. The drugs are highly protein bound but do not affect serum digoxin concentrations. Anticonvulsants may reduce the elimination half-life of felodipine. Felodipine and isradipine are effective antihypertensive agents when used alone or in combination with beta blockers or diuretics. Both agents have shown some benefit in the treatment of angina pectoris in limited studies. Clinical data do not support the use of either agent for the treatment of congestive heart failure or Raynaud's phenomenon. Felodipine and isradipine have similar adverse-effect profiles, and their adverse effects resemble those of other agents in the class. Common adverse effects are peripheral edema and increased heart rate. The initial dosage of isradipine for the treatment of hypertension is 2.5 mg twice daily. Felodipine should be started at a dosage of 5 mg once daily. Felodipine and isradipine are effective antihypertensive drugs but have not demonstrated clear advantages over other dihydropyridine calcium-channel blockers.
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PMID:Felodipine and isradipine: new calcium-channel-blocking agents for the treatment of hypertension. 845 78


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