Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0012833 (dizziness)
 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID: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. 171 8

Felodipine, a dihydropyridine calcium-channel antagonist, significantly reduces systolic and diastolic blood pressure (BP) in patients with hypertension and has been associated with beneficial hemodynamic effects in patients with chronic stable angina pectoris or congestive heart failure (CHF). In hypertensive patients, felodipine does not appear to significantly affect glomerular filtration rate, creatinine clearance, glucose tolerance, or plasma lipoprotein concentrations. Studies comparing felodipine with other agents as monotherapy in mild to moderate hypertension have demonstrated felodipine to be at least as efficacious as hydrochlorothiazide (HCTZ) and HCTZ plus amiloride hydrochloride in combination. Comparisons of felodipine with other agents as adjuncts to beta-blocker or diuretic therapy have shown felodipine to be at least as effective as HCTZ, propranolol hydrochloride, prazosin hydrochloride, and nifedipine. Evaluations of patients with chronic stable angina are limited, and additional studies are needed before felodipine can be recommended for the routine management of angina pectoris. Similarly, additional studies are essential to delineate the role of felodipine, if any, in the management of CHF. In the management of hypertension, felodipine 5-40 mg/d significantly reduces systolic and diastolic BP. Although some patients may be controlled throughout the entire dosing interval when felodipine is administered bid, many patients will require more frequent dosing to obtain adequate BP control. Adverse effects associated with felodipine are similar to those of other dihydropyridine calcium-channel antagonists and include peripheral edema, headache, dizziness, flushing, and fatigue. A potentially clinically important drug interaction was observed when felodipine was administered concomitantly with theophylline aminopropanol; significant decreases in theophylline concentrations were noted. In summary, felodipine appears to be safe and effective for the management of hypertension when used alone or in combination with other antihypertensive agents. The efficacy of felodipine in the management of chronic stable angina pectoris and CHF requires further investigation.
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PMID:Felodipine: a new dihydropyridine calcium-channel antagonist. 176 37

It has been suggested that autoimmunity and genetic factors may play a specific role in the development of idiopathic hypoparathyroidism. We reported a case of idiopathic hypoparathyroidism complicated with chronic thyroiditis. The patient, a woman 40 years old, visited our clinic because of tetany of both hands and dizziness. She was of short stature with a round face. She also had a goiter, hypocalcemia, hyperphosphatemia and decreased parathyroidal function, but renal function was normal. Her TSH level was slightly high with a positive microsome test (x 1600), and the levels of thyroid hormones tended to be low. Based on Ellsworth-Howard test findings, a diagnosis of idiopathic hypoparathyroidism was made, with the complication of chronic thyroiditis confirmed by the thyroidal biopsy. Administration of l alpha-OH-D3 normalized the level of serum calcium. No special treatment was given for the chronic thyroiditis in order to observe its natural course. Her TSH returned to normal, and the level of thyroid hormones was increased to normal ranges. Tests were positive for anti-adrenal antibody and anti-gastric antibody. The complication of chronic thyroiditis, an autoimmune disease, and a positive finding for every antibody suggested the possible involvement of autoimmunity in the mechanism of development of idiopathic hypoparathyroidism. The administration of 1 alpha-OH-D3 resulted in an increase in the serum calcium level and also normalization of levels of TSH and thyroid hormones. Thus, it is likely that the elevation of the calcium ion or immunoregulation by active vitamin D may have induced the increase in thyroid hormone secretion.
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PMID:[A case of idiopathic hypoparathyroidism complicated with chronic thyroiditis]. 178 1

Isradipine is a new dihydropyridine calcium antagonist with a high degree of selectivity for the coronary, cerebral, and skeletal muscle vasculature. The drug has minimal depressant activity on sinoatrial node automaticity and negligible negative chronotropic, dromotropic, and inotropic actions. Isradipine reduces blood pressure and systemic vascular resistance without changes in cardiac output and stroke volume. Renal blood flow is maintained while renal vascular resistance is reduced; this is accompanied by both short- and long-term diuretic and natriuretic effects. Doses of 1.25 to 5 mg twice daily lowers blood pressure effectively over 24 h. In open as well as placebo-controlled trials, 2.5 to 10 mg isradipine twice daily was safe and well tolerated, and reduced systolic and diastolic values in up to 85% of patients with mild-to-moderate hypertension. Efficacy is similar to those of nifedipine and nitrendipine, and potentially superior to those of propranolol, atenolol, prazosin, hydrochlorothiazide, and diltiazem. The drug can be safely combined with beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and diuretics. Adverse effects are dose-dependent and secondary to arterial vasodilatation, such as headache, flushing, ankle edema, dizziness, palpitations, and tachycardia. At the recommended dose of 2.5 mg twice daily, the total incidence of side effects does not differ from that with placebo. The antiatherosclerotic, antitrophic, and cerebroprotective effects seen in experimental animal models are promising for the drug in the treatment of human hypertension. Isradipine may not only reduce blood pressure, but may also reduce the risk for the consequences of this peril, namely, cerebral stroke and myocardial infarction.
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PMID:The place of isradipine in the treatment of hypertension. 182 26

The purpose of this study was to evaluate the antihypertensive effect of a new calcium antagonist, clentiazem, on inpatients or outpatients with essential hypertension. After blood pressure was stable and greater than 160/95 mmHg with placebo for at least a 2-week observation period, oral clentiazem was administered once daily and dosage was increased stepwise from 10 to 40 mg over 10 weeks. Blood pressure significantly decreased by the second week of the study, and this hypotensive effect was maintained until the eighth week. Cumulative effective rate (percent of patients whose blood pressure decreased in 20/10 mmHg) in 62 outpatients were as follows; 10.3% at 10 mg, 39.6% at 20 mg, 70.2% at 30 mg, 76.6% at 40 mg. There was no significant postural change observed in the blood pressure from supine to standing position. Side effects such as dizziness, general malaise and gait disturbances were observed in 3 (3.9%) of 76 patients. No abnormal changes in clinical laboratory examinations or electrocardiograms were caused by clentiazem. Thus these data demonstrated that clentiazem produces certain antihypertensive effects with sufficient safety.
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PMID:Efficacy and safety of clentiazem in patients with essential hypertension: results of an early pilot test. 201 30

Tiapamil (T), a calcium antagonist, was studied in hypertensive patients by 1) automatic monitor of blood pressure (AMBP), and 2) cuff and stethoscope clinic blood pressure (CBP). Systolic (SBP), diastolic (DBP) pressures and heart rate were measured. Patients (n = 58) received four weeks of placebos given twice daily. Baseline 24 h AMBP (wk 4), 147 +/- 18 (SBP) and 91 +/- 8 (DBP) mmHg; and CBP (wk 3 and 4), 152 +/- 16 (SBP) and 102 +/- 9 (DBP) were established. Then, patients received double-blinded therapy (wk 5-10) of twice daily tablets of placebo (n = 9); Level I T, 150-300 mg (n = 24); or Level II T, 450-600 mg (n = 25): i.e. 0 to 1,200 mg T/d. Significant responses, measured by AMBP (wk 10), were noted only at Level II T: SBP (-10.5 +/- 12.4) and DBP (-5.6 +/- 7.8) mmHg. However, CBP (wk 9 and 10) responded at Level I T (SBP, -7.7 +/- 12.4/DBP, -5.8 +/- 6.4) and Level II T (SBP, -8.8 +/- 9.4/DBP, -9.7 +/- 7.8 mmHg). There was minimal correlation (r = 0.16) of pressure responses to T measured by 24-h AMBP versus CBP methods. Therefore, T effectively lowered SBP and DBP, but individual responses measured by AMBP did not predict those measured by CBP. There was no effect of T on heart rate. Dizziness was noted in 12 percent of patients on T.
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PMID:Antihypertensive effect of tiapamil from ambulatory and clinic methods. 202 64

Because of the benefit-risk ratio in their favor, calcium channel antagonists are considered to be a safe form of treatment of hypertension in the elderly. However, the outcome of dizziness in some patients over 65 yr old during the first few days of treatment with these drugs has to be considered. Five cases of "malaise" have been mentioned, which occurred during the first few days of treatment. The imputability of the drug in question has been evaluated. Additional factors have been found, ie orthostatic hypotension whatever its mechanism, and association with diuretics, with or without hyponatremia. The above-mentioned cases led to a study in 10 supine elderly women (mean age 85 +/- 3 yr) with normal blood pressure. In this study, systolic and diastolic blood pressure were monitored after a 20-mg oral dose of nicardipine for 3 h. Even in the supine position, a significant fall in blood pressure was observed as early as the 15th min after administration, which could be significant, occasionally reaching 45% of the initial value. Before administering a calcium channel antagonist to an elderly person, orthostatic hypotension has to be investigated. Association with a diuretic results in high risk due to hypovolemia that can enhance the vasodilatory effect of calcium antagonists.
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PMID:Dizziness in the elderly and calcium channel antagonists. 204 56

Cadralazine is a peripheral arteriolar vasodilator which, unlike hydralazine or dihydralazine, has a protected hydrazino group. In hypertensive patients the optimal effect, based on the antihypertensive efficacy to tolerability ratio, is seen after a 15 mg dose when the drug is administered as monotherapy. When administered in combination with other antihypertensive agents, a 10 mg daily dosage seems appropriate. Noncomparative trials have shown that, in patients who had failed to respond adequately to a beta-blocker and/or diuretic, the addition of cadralazine 10 to 30 mg once daily reduced systolic/diastolic blood pressure by 11 to 19%/13 to 22%. This antihypertensive effect becomes evident over a 2- to 6-week period of therapy and persists during longer term administration. Comparative studies have shown that cadralazine is superior to placebo, and has a similar blood pressure lowering effect to hydralazine, dihydralazine and prazosin in patients not controlled by beta-blocker and/or diuretic but who continued to receive these treatments. Similarly, cadralazine and chlorthalidone were equally effective in reducing blood pressure in resting hypertensive patients but cadralazine shows an advantage in reducing the pressor response in exercising patients. Cadralazine is well tolerated when administered with a beta-blocker or diuretic. Most adverse effects become less frequent and severe with continued use, occur more frequently at dosages of 20 mg/day or more, and do not generally require withdrawal of therapy. Manifestations of the drug's vasodilating properties such as headache, asthenia, dizziness, palpitations and flushing are the most commonly reported symptoms during cadralazine monotherapy, but these may be reduced during combination therapy. The drug does not appear to induce a systemic lupus-like erythematosus syndrome, as may occur with hydralazine, but additional clinical experience is required to completely exclude this possibility. In conclusion, because of its efficacy as a second- or third-line antihypertensive agent, its simple once daily dosage regimen and favourable risk: benefit ratio, cadralazine may have a useful role, particularly in those hypertensive patients who do not respond adequately to established antihypertensive treatments. However, the therapeutic potential of cadralazine cannot be clearly established until the present limited clinical base is expanded to include comparisons with other classes of vasodilating drugs (ACE inhibitors and calcium antagonists), and its utility in the management of other indications such as severe hypertension during pregnancy has been adequately explored.
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PMID:Cadralazine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in the treatment of hypertension. 208 13

Isradipine is a dihydropyridine calcium-entry blocking agent with pronounced vasodilator activity and no significant cardiac effects at clinical doses, a desirable profile for an antihypertensive drug. Prazosin, a post-junctional alpha-adrenoceptor blocking agent, may produce a similar hemodynamic pattern. Therefore, we compared the effects of isradipine (2.5-10 mg bid) with those of prazosin (2-8 mg bid) in 83 patients with established essential hypertension, using a randomized, double-blind, parallel-group design. Patients received a placebo for 3-5 weeks, then either isradipine or prazosin over a 6-week titration period, followed by a 4-week plateau phase. During the plateau period, isradipine therapy lowered sitting blood pressure more effectively than did the administration of prazosin: Mean systolic BP fell 16.7 versus 8.1 mmHg (p less than 0.001) and mean diastolic BP was reduced 15.6 versus 12.6 mmHg (p less than 0.01). In the dosing range used (while also noting that prazosin is occasionally titrated up to doses of 30 mg qd), 83% of isradipine-treated patients had at least a 10 mmHg reduction in diastolic BP, compared with 64% of prazosin-treated patients (p = 0.05, FET). Tachyphylaxis did not occur with either drug. The rate of occurrence of side effects was similar in both treatment groups; the most common adverse event seen with isradipine was headache (20%) and with prazosin, dizziness (19%).
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PMID:A multicenter comparison of isradipine and prazosin for treatment of essential hypertension. 214 12

Dilevalol, the RR-stereoisomer of labetalol, is a non-cardioselective beta-adrenoceptor antagonist with substantial partial beta 2-agonist and negligible alpha 1-blocking activity. Reduction in blood pressure during dilevalol administration is associated with peripheral vasodilatation, and heart rate remains essentially unchanged. Following oral administration, dilevalol is completely absorbed. Once-daily administration is possible, due to a long elimination half-life. Large well-controlled trials reveal that dilevalol is equivalent in antihypertensive efficacy to metoprolol, the ACE inhibitors captopril and enalapril, and the calcium antagonist nifedipine. Smaller noncomparative and comparative trials demonstrate the blood pressure-lowering effects of dilevalol and suggest an efficacy at least equivalent to that of the 'pure' beta-blockers atenolol and propranolol and the alpha 1-blockers urapidil and doxazosin. Dilevalol appears to be well tolerated, the most frequent adverse effects being dizziness, headache and diarrhoea in only about 7% of patients each. Unlike alpha 1-blockers and labetalol, dilevalol is not commonly associated with orthostatic hypotension. Thus, data suggest that dilevalol, with its distinctive pharmacological profile, is likely to be a useful addition to the options currently available for treating patients with mild to moderate essential hypertension.
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PMID:Dilevalol. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in hypertension. 218 2


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