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Biomedical subjects

Y Munera

Publications and source records attributed to Y Munera.

13 recordsLinked to original sources
PubMed1992

[Drug induced orthostatic hypotension].

Therapeutic drugs are the main cause of postural hypotension, notably in elderly people. This syndrome is harmful as it reduces patients' compliance with treatment and is responsible for severe accidents. Drugs which lower cardiac output by acting on heart rate and cardiac muscle contractility, and drugs which decrease blood volume may produce postural hypotension; diuretics are often responsible for hypovolemia and hypokalaemia. The principal mechanisms involved are interferences of drugs with vegetative blood pressure regulation. They include vasomotor centre depressors (morphine-like compounds, antihypertensive agents, neurosedatives, neuroleptics, antiparkinsonians); ganglioplegics; inhibitors of noradrenaline production (methyldopa, disulfiram) or re-uptake (antidepressants); catecholamine depressors (guanethidine); drugs acting on chromaffin granules (monoamine oxidase inhibitors) and those which inhibit post-synaptic receptors (alpha- and beta-blockers). Drugs which act on vascular smooth muscle tone (nitrites, calcium channel antagonists, angiotensin-converting enzyme inhibitors) occasionally cause postural hypotension. To the actions of these drugs must be added endogenous and exogenous factors and notably physiological ageing of the baroceptor reflex; these factors must be taken into account whenever therapeutic drugs are prescribed.

Adolescent↗
PubMed1991

Dizziness in the elderly and calcium channel antagonists.

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.

Aged↗
PubMed1991

[Cardiovascular responses to passive and active orthostatism in healthy subjects, in relation to age].

Changes in heart rate induced by inclining an orthostatic table to 30 degrees and 60 degrees and by standing was studied in 200/healthy volunteers of either sex. Study subjects were divided in eight ten-year age groups, from 16 to 97 years. The 56-65 year age group was the youngest group to develop systolic orthostatic hypotension. This response occurred in 4% of subjects aged 56-65 years and became increasingly prevalent from one age group to the next (25%, 36% and 44%). In some patient, the fall in systolic BP reached 70 mmHg. Systolic hypotension occurred in some patients at 30 degrees but in most cases developed only at 60 degrees. No significant difference was found between the falls in SBP seen at 60 degrees and during active standing (90 degrees), indicating that muscular activity does not play a major role in BP regulation. Diastolic hypotension was less common and was mainly seen in patients above 75 (20%) who also had systolic hypotension. Orthostatism was responsible for tachycardia but this response became increasingly less common beyond 55 years of age (60, 60, 52 and 36% in the four age groups above 55). This reflects increasing loss of sensitivity of the baroreflex with advancing age. These date are useful for comparing the age-specific effects of disease states (e.g. diabetes mellius, alcohol abuse) or treatments (psychoactive drugs, antihypertensive agents).

Adolescent↗
PubMed1990

Systemic effects of three beta-blocker eyedrops: comparison in healthy volunteers of beta 1- and beta 2-adrenoreceptor inhibition.

The beta 1- and beta 2-adrenoreceptor blockade by means of the systemic diffusion of three beta-blocker eyedrops--timolol, carteolol, and betaxolol--was evaluated in a randomized, single-blind, three-way crossover study in 18 volunteers. The blockade was evaluated by analyzing the variations of the beta 1- and beta 2-blockade effects of isoproterenol before and after instillation of one drop in each eye. The beta 1-blockade effect was judged on the variation of heart rate, and the beta 2-blockade effect was judged on the change in peripheral blood flow measured by veno-occlusive plethysmography. Comparison of the blockade by these drops showed that carteolol and timolol totally inhibited the beta 1 and beta 2 effects of a dose of isoproterenol able to increase heart rate by 50% (placebo eyedrops were used as a control). Betaxolol differ significantly because it allowed the same effects with the same dose of isoproterenol. Intensity of the blockade was measured by comparison of the effective doses of isoproterenol. Carteolol and timolol were shown to be four times more inhibitory.

Adrenergic beta-Antagonists↗
PubMed1979

[Symptomatology in 162 patients with spasmophilia (chronic idiopathic or constitutional tetany). A statistical analysis using a computer (author's transl)].

A computer was used for a statistical analysis of the results of treatment in 162 patients (130 women and 32 men with an average age of 29 years), with chronic idiopathic tetany. Symptoms leading to diagnosis were mainly feelings of ill-health (27.2 %), motor disorders (19.7 %), and sensory problems (19.1 %). The onset of acute attacks is related, more especially, to psychogenic factors. The frequency of the various clinical manifestations, and their symptomatic grouping were analyzed. The clinical profile is similar in both sexes apart from 7 of the 89 items: lipothymia, abnormal feelings of warmth, pseudo-contraction of the larynx, abnormalities of the exoskeleton, and digestive disorders are more frequent in women, while precordalgia is more often present in men. Factorial analysis of correspondence between 38 variables reveals a very large dispersion of the variables, as the first three factors, which are the most significant, supply only 30% of the total information. Furthermore, very few variables share significant relationships in each factor. In spite of the amount of information collected, this dispersion of the symptomatology does not permit the definition of one or more profile-types of spasmophilia.

Acute Disease↗
PubMed1976

[Asthma and propranolol].

The authors report the results of a study of propranolol perfused intravenously at a dose of 1 mcg/kg/mn during 30 mn to 50 asthmatic patients. The VC decreased by 8.3 and by 10.9% in the middle and at the end of the perfusion. The FEV1 decreased by 18.3 and 23% concomitantly. Classifying patients in 4 groups according to the clinical severeness of the asthma showed that the response to propranolol increased with that severenesse. Exploration of obstructive bronchopneumopathies by propranolol provided valuable data or the differential diagnosis of asthma and chronic bronchitis.

Adult↗