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)

Isosorbide dinitrate (ISDN) improves the clinical and hemodynamic state of patients with heart failure, but may cause dizziness and syncope. To characterize patients in whom cardiac output falls with high-dose nitrate therapy and to examine further the pathophysiology of the fall in cardiac output in these patients, we studies the effect of sublingual ISDN on forward cardiac output in 14 patients with severe cardiac failure (New York Heart Association grades 3-4). We examined systolic and diastolic left ventricular (LV) function from pressure and volume analyses of LV function. After administration of 15 mg ISDN, cardiac output was either unaltered or increased in 7 patients (Group 1) (11 +/- 12%, mean +/- SD), and decreased in 7 (Group 2) (-13 +/- 10%) (Group 1 vs. 2, p less than 0.002). Initial systemic arterial pressure, LV ejection fraction, wedge and LV transmural filling pressures were similar in both groups, but Group 2 patients had a lower systemic vascular resistance (p = 0.07) and tended to have a larger initial LV end-diastolic volume and increased end-diastolic compliance; following ISDN the decrease in LV filling pressure and end-diastolic volume was larger and the product of the changes greater (p less than 0.02). Thus ISDN decreases filling pressure and improves forward cardiac output in some patients with congestive heart failure, but large doses may decrease cardiac output in a subset of patients who have a lower systemic vascular resistance and a larger more compliant ventricle, maintaining forward blood flow predominantly by a preload reserve mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of isosorbide dinitrate on cardiac output in severe cardiac failure: relation to initial hemodynamics, ventricular volume, and the preload reserve mechanism. 279 73

Among 509 patients referred to our Institute for Holter monitoring, between 1st September, 1982-30th October, 1983, 28 patients aged 65-90 (mean 76) were referred for dizziness and syncope. There were 17 men and 11 women. Seven patients had a M.I. in their past, 4 angina pectoris, 5 hypertension, 4 aortic stenosis or aortic insufficiency or both, hemodynamically significant, one had mitral valve prolapse (MVP) and one transient ischemic attacks (TIA). In our series 16 out of 28 patients received digoxin and antiarrhythmic drugs (quinidine, propranolol, procainamide, Neo-gilurythmal, amiodarone), 2 of them digoxin and quinidine in full doses and one digoxin and amiodarone. Other drugs administered to our patients included Aldomin, Isordil, Lasix, aminophylin, cromoglycate etc. In 10 patients (35.7%) we found complex ventricular arrhythmias (7 with M.I., 3 patients of 4 with significant aortic valve lesion, 2 patients of 2 with left anterior hemiblock (LAH), 1 patient with MVP, 1 patient with TIA). In another 5 patients (17.8%) we found atrial fibrillation, fast rhythm (2 with chronic obstructive lung disease, 2 with hypertension and 1 in post M.I.) which explained their symptomatology. From our data we conclude that the pluripathology found in old age as well as the multimedication administered, cause a plurietiology of syncope, arrhythmias playing an important role in its determination, in this particular age group.
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PMID:Holter monitoring for dizziness and syncope in old age. 387 98

Isosorbide-5-mononitrate (IS-5-MN) 5, 10, 20, 30, 40 and 50 mg were administered orally to 2 healthy male volunteers. The pharmacological effect was determined using digital pulse plethysmography and the orthostatic tilting test, and at the same time side effects were monitored. The threshold of oral activity of IS-5-MN was found to be 5 mg. The maximum response was reached with doses of 20-30 mg. The duration of action of this dose was approximately 8 h. Higher doses did not lead to any further increase, but rather to a decrease in the pharmacological response, while the side-effects, such as headaches, dizziness and nausea, became more prominent. In a randomized, double-blind, three-way cross-over study in 11 female volunteers IS-5-MN 30 mg proved to be more potent with respect to pharmacological activity than sustained released ISDN 20 mg (isosorbide dinitrate), whereas there was no difference in side-effects. Thus, it can be estimated that IS-5-MN 20 mg is approximately equivalent to 20 mg sustained released ISDN. IS-5-MN is rapidly absorbed after oral administration and the maximum concentration in serum was reached 1.2 +/- 0.2 h after doses of 10 to 50 mg. The pharmacokinetics showed dose-linearity. The compound was eliminated with an average half life of 4.04 +/- 0.16 h, which is appropriate for a reasonably prolonged duration of action without the need for a sustained release formulation.
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PMID:First data on effects and pharmacokinetics of isosorbide-5-mononitrate in normal man. 725 Jan 75