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Query: UMLS:C0012833 (dizziness)
 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A double blind control comparison on the effects of 50 mg of clomipramine given three times a day and 150 mg of clomipramine in a single bedtime dosage revealed no significant differences in therapeutic efficacy. Patients reported more lightheadedness and dizziness but no differences on other side effects. The theoretical basis was the long biological half-life of such tricyclic antidepressants. Advantages included ease of administration, patient compliance, and timing of sedative effect.
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PMID:Are divided doses of tricyclic antidepressants necessary? 36 77

An investigation of a case of apparent mass psychogenic illness was undertaken in a midwestern electronics assembly plant. The plant employed 500 workers, of whom 80% were female. The illness outbreak involved a total of 90 female first shift workers who reported a variety of nonspecific symptoms such as headache, dizziness, and lightheadedness in response to a strange odor in the workplace. Although environmental testing revealed some localized concentrations of a few airbone contaminants, no environmental toxins were discovered that could account for the continuing outbreaks of illness. An ad hoc sample of affected and nonaffected workers was surveyed to assess the influence of psychological, sociological, and work environment factors in the outbreak. Analysis of the data revealed that affected workers reported more physical discomfort (temperature variations, poor lighting) in the workplace as well as psychological job stress (increase in workload, conflicts with supervisors) than did nonaffected workers. Moreover, affected workers scored significantly higher than nonaffected workers on personality tests measuring extraversion and hysteria traits.
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PMID:An investigation of apparent mass psychogenic illness in an electronics plant. 53 40

Eight patients with frequent premature ventricular contractions (PVCs) were given single oral doses of 2-amino-2', 6'-propionoxylidide hydrochloride (APX), a lidocaine congener, to investigate the drug's efficacy, toxicity, and pharmacokinetics. Of the 7 patients receiving more than 100 mg, 5 demonstrated at least 60% reduction in PVCs in the 5-hour period following one of the doses; the responsiveness to APX was similar to that observed when intravenous lidocaine was given to the same patients. There were side effects of transient dizziness, lightheadedness, and nausea in 3 patients 20 to 30 min after doses of 400 to 800 mg; slightly smaller doses in 2 of these patients retained efficacy without side effects. There were no effects on arterial blood pressure, heart rate, or the electrocardiogram of normally conducted beats. Laboratory values remained within normal limits, although the hemoglobin level and hematocrit showed a small but significant fall probably related to repeated blood sampling during the study. Drug plasma levels at 1 and 2 hr after administration and the area under the plasma concentration-time curve were proportional to dose, and the drug disappeared with a mean elimination half-life of 14.7 +/- 1.7 hr (mean +/- SD). Plasma levels resulting in suppression of PVCs ranged from 1 to 5 mug/ml. A mean of 39.7 +/- 12.4% of an orally administered dose was recovered unchanged in 48-hr urine collections. Comparison of the present results with those previously obtained after intravenous administration of APX indicates that oral bioavailability of the drug was essentially complete. APX appears to be a promising orally effective antiarrhythmic drug with suitable pharmacokinetic characteristics to warrant studies designed to establish dosage regimens for chronic therapy.
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PMID:Antiarrhythmic effects of a lidocaine congener, tocainide, 2-amino-2',6'-propionoxylidide, in man. 77 80

As part of an epidemiological study of hypertension, an analysis was made of the general practitioner records of all attenders at a screening survey. A blood pressure recording, made before screening, was found in 37-9 per cent of cases. The pressures obtained correlated well with those obtained by the screening unit, though the practitioners' readings tended to be lower. Further cases of hypertension were found, not diagnosed by the screening unit; the estimate made of the prevalence of hypertension at the survey could be corrected by inclusion of these cases. Chest pain, headaches, lightheadedness, and dizziness were common reasons for blood pressure measurement in general practice, but these symptoms were not associated with a rise in the blood pressure; symptoms were not helpful in the diagnosis of hypertension. Some form of screening programme is necessary to detect cases of hypertension. This could be carried out by general practitioners.
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PMID:Blood pressure measurement at screening and in general practice. 83 40

The case of a 22-year-old white male without known heart disease who presented with activity related lightheadedness at age 19 and dizziness and fatigue at age 21 is described. Standard electrocardiograms (ECG's) revealed intermittent complete trifascicular block. Rapid progression of symptoms over the succeeding eight months resulted in increasing incapacity. Holter monitoring demonstrated that symptoms were related to development of second and higher degrees of A-V block. Normal A-H interval and markedly prolonged H-Q interval on His bundle electrograms indicated that block was infranodal and localized to bundle branch system. Conduction problems aside, clinical and laboratory evaluation, including echocardiograms and cardiac catheterization, were unremarkable. Progression of bilateral bundle branch disease in a young patient without other demonstrable heart lesions and a negative family background conforms with criteria for Lenegre's disease. To our knowledge, this represents the youngest reported patient with this entity. Possible electrophysiologic basis of block and of exercise induced improvement in A-V conduction also are considered.
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PMID:Lenegre's disease in youth. 91 Jun 82

In a 14-month period mitral leaflet prolapse was diagnosed in 85 patients by echocardiography or cineangiography. Chest pain alone was the presenting complaint in 30 patients and linked with palpitation, dyspnoea, or syncope in 9. Eleven presented with major neurological disturbances (9 had transient ischaemic attacks), 10 with palpitation, 4 with undue and persistent fatigue, 2 with dyspnoea, and 2 with dizziness. Seventeen were referred not because of symptoms but because of clicks and murmurs. Overall, chest pain affected 61 patients and unless associated with coronary artery disease was not anginal. Palpitation was admitted by 42 patients; dizziness, lightheadedness, or paraesthesiae by 15, and syncope by 12. Systolic auscultatory abnormalities were noted in 69: 25 had single clicks, 3 had multiple clicks, 19 had both click(s) and murmur, and 22 had a murmur alone. Electrocardiography revealed ST segments flat for greater than 0-10 s in 21, prolonged QTc in 18, and T wave flattening or inversion in inferior limb and lateral chest leads in 14. The exercise stress test was abnormal in 13 of 27 patients. Mitral valve echograms showed definite mitral leaflet prolapse in 61, 'possible' prolapse in 14, and were normal in 8 patients with angiographic proof of mitral leaflet prolapse. Cardiac catheterization with left ventriculography showed prolapse of posterior mitral leaflet in 36, of both leaflets in 2, and left ventricular wall motion abnormalities in 16 cases. Selective coronary arteriography in 31 cases showed major vessel narrowing of larger than or equal to 80 per cent lumen diameter in 4, all with angina. This consecutive series indicates that the physical event of mitral leaflet prolapse is more common than hitherto appreciated, is priminently associated with non-anginal chest pain, palpitation, and neurological disturbances, and in 90 per cent of cases could be shown echocardiographically.
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PMID:Clinical features and investigative findings in presence of mitral leaflet prolapse. Study of 85 consecutive patients. 125 39

The bioavailability of sodium salicylamide (NaSAM) in solution of salicylamide (SAM) tablets was compared in 6 healthy human volunteers. Bioavailability was assessed by plasma level determinations of nonmetabolized salicylamide (free SAM) and salicylamide plus conjugated metabolites (total SAM) for 3 hr following oral doses of 0.65, 1.30, 1.95, and 2.60 gm of salicylamide. The availability of NaSAM was found to be superior to SAM and dose-dependent. Mean peak levels of free SAM and total SAM were higher and were reached earlier after NaSAM liquid than after SAM tablets. Significantly higher mean levels of free SAM were found at the 1.95 and 2.60 gm dose levels after NaSAM administration than after SAM. Mean total SAM concentration was significantly higher after NaSAM at all dosage levels. The sedative effects of salicylamide were assessed with a self-scoring questionnaire. Sedation seemed to increase with increasing dose of both NaSAM and SAM. The sedative response occurred earlier after NaSAM than after SAM. Side effects were minor and transient in nature, occurred at the higher dosage levels, and were predominantly lightheadedness and dizziness. Because NaSAM produces higher drug levels and has a more rapid onset of subjective effects, we conclude that it represents a potentially superior dosage form.
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PMID:Sodium salicylamide: relative bioavailability and subjective effects. 126 96

Hyperventilation is of little clinical relevance unless it causes symptoms. These are often non-specific. Their threshold for onset and relation to steady level of arterial (or its equivalent, end-tidal PCO2; PETCO2) are uncertain, and it has been suggested that they may relate better to the rate of fall of PCO2 than to the absolute level. We investigated this in nine normal subjects, who breathed to and fro through a pneumotachograph into an open circuit in which the concentration of CO2 could be varied. Tidal volume, respiratory frequency and ventilation was measured on-line by a Compaq computer, and PETCO2 at the mouth was measured by capnograph. Subjects overbreathed at a fixed rate and depth until symptoms consisting of dizziness, paraesthesiae and light headedness occurred. Then, without their knowledge and while they continued to overbreathe, inspired CO2 was increased to restore PETCO2 to normal and abolish symptoms, and was then withdrawn again over either approximately 0.1, 2.5 or 5 min until symptoms were again reported. The PETCO2 at this point was noted. The three protocols were performed in each subject in a random order and the same symptoms were reported each time. When averaged across all subjects, symptoms occurred at mean PETCO2 values of 20.3, 19.2 and 18.6 mmHg (2.71, 2.56 and 2.48 kPa), respectively. These were not significantly different, and it can be concluded that there was no influence of rate of fall of PCO2 on threshold for symptoms. Chest pain only occurred in one subject and may have a different mechanism.
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PMID:Relation of hypocapnic symptoms to rate of fall of end-tidal PCO2 in normal subjects. 144 88

A cross sectional study of biological markers of neurochemical function in peripheral blood cells, and self reported nervous system symptoms, was conducted among 60 workers exposed to styrene in three reinforced plastics plants and 18 reference workers not exposed to styrene or other solvents. Concentrations of styrene in the air at the plants ranged from less than 1 to 160 ppm. Biomarkers of neurochemical function measured were: sigma receptor binding in lymphocytes, monoamine oxidase type B (MAO-B) activity in platelets, and serotonin uptake by platelets. Blood styrene concentration was used as the exposure index to take account of the use of protective equipment and dermal uptake. Four blood styrene exposure groups were defined as: non-exposed (reference) and exposed to less than 0.05, 0.05-0.19, and greater than or equal to 0.20 micrograms/ml. The prevalences of headache, dizziness, light headedness, fatigue, irritability, memory loss, and feeling "drunk" at work increased with increasing blood styrene concentration. No effect on sigma receptor binding was seen. A slight positive correlation was found for uptake of serotonin, which has been used as an exposure related effect indicator in previous studies of workers exposed to solvents. The MAO-B activity decreased with increasing blood styrene concentration; the mean (SE) MAO-B values for the four groups were 34.2 (3.0), 28.1 (5.3), 20.1 (4.8), and 16.9 (7.7) pmol/10(7) cells/min. The MAO-B activity also correlated negatively with the number of reported nervous system symptoms, whereas no associations were seen between prevalence of symptoms and either serotonin uptake or sigma receptor binding. The findings for MAO-B activity are consistent with previously reported experimental data, and suggest that MAO-B may be a useful marker of styrene neurotoxicity.
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PMID:Peripheral markers of neurochemical function among workers exposed to styrene. 151 48

Forty cancer patients receiving parenteral chemotherapy were assessed for characteristics associated with the development of anticipatory nausea and vomiting (ANV). The patients who developed ANV were more likely to have increased pretreatment anxiety (p less than 0.05), greater posttreatment dizziness/lightheadedness (p less than 0.01), more severe postchemotherapy vomiting (p less than 0.01), and a delayed onset of postchemotherapy nausea and vomiting (PCNV) compared to the patients who developed neither ANV nor PCNV. However, when patients who did not develop PCNV were excluded from the analysis, the difference between the ANV and non-ANV patients remained significant only for postchemotherapy dizziness/lightheadedness (p less than 0.05). In an attempt to identify a group of variables that better predict the development of ANV, we analyzed the data for combinations of variables. Two indices were found to correctly classify ANV and non-ANV patients 71% of the time (p less than 0.05). Index A refers to the presence of at least two of the following variables, pretreatment anxiety, posttreatment dizziness/lightheadedness, and latency of PCNV. Index B refers to the presence of at least two of the following variables: pretreatment anxiety, severity of nausea, and severity of vomiting. The identification of characteristics associated with the development of ANV could lead to new intervention strategies.
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PMID:Variables contributing to anticipatory nausea and vomiting in cancer chemotherapy. 159 Feb 83


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