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Biomedical subjects

P Vestergaard

Publications and source records attributed to P Vestergaard.

At least 55 records · Page 3Linked to original sources
PubMed1984

Heart rate variation in patients treated with antidepressants. An index of anticholinergic effects?

The aim of the present study was to investigate whether heart rate variation as obtained simply from an electrocardiographic registration is influenced in subjects given antidepressive medication. The mean difference between consecutive R-R intervals (MCD) was reduced in patients (n = 23) treated with various doses of tri- or tetracyclic antidepressants [7.7 (1.8-32.3) ms in patients versus 24.8 (7.0-87.7) ms in controls]. Among those receiving 1.67 mg tricyclic antidepressant or more per kilogram body wt (n = 12) MCD was further reduced [5.0 (2.1-12.0) ms] with no overlapping of values as compared to controls (n = 9). In a subgroup of patients treated with clomipramine the MCD was related inversely to the dosage (R = 0.78, P less than 0.02). In an additional group of seven patients, MCD was reduced following a few days of treatment with antidepressants as compared to pretreatment values (P less than 0.02), indicating that the reduction is a result of therapy and not a concomitant of the affective state. We suggest that measurements of heart rate variation could be a useful tool to measure anticholinergic effects of antidepressants.

Adult↗
PubMed1984

The effect of age on lithium dosage requirements.

Analysis of more than 350 observations of patients who had been under lithium treatment for 6 months to 4 years showed a significant negative correlation between dosage requirements and age; old patients required less lithium than young patients to maintain a particular serum lithium concentration. The decline in dosage requirement with increasing age could be fully accounted for by the age-dependent fall in the glomerular filtration rate and lithium clearance. There was no age-dependent change in tablet compliance, and the duration of exposure to lithium did not influence the dosage requirement.

Adult↗
PubMed1983

Patient attitudes towards lithium.

Many patients discontinue prophylactic lithium treatment against medical advice. Knowledge of patient attitudes towards lithium treatment may help explain and prevent non-compliant behaviour. One hundred and forty patients given lithium treatment from 2 to 17 years were asked what they found most advantageous about the treatment and what they found most disadvantageous. Seventy-five per cent of the patients experienced freedom from symptoms and the reestablishment of social functions in the family and in work as the main benefit of the treatment. Twenty-five per cent perceived no other advantages than possibly the satisfaction of demands from the family or the doctor. Seventy per cent of the patients considered various somatic and non-somatic complaints the main disadvantage of lithium treatment and 30% found no disadvantages at all. Psychological and other non-somatic complaints related to work, training, patient status, and the administration of lithium tablets were almost as frequent as somatic complaints. The advantages and disadvantages perceived by the patients did not necessarily correspond with the physician's perception of good or bad treatment response or the presence of unwanted effects.

Adult↗
PubMed1982

Lithium treatment regimen and renal water handling: the significance of dosage pattern and tablet type examined through comparison of results from two clinics with different treatment regimens.

For many year two Danish psychiatric hospitals having used different lithium treatment regimens. In one, slow-release tablets were given in two daily doses and, in the other conventional tablets were given in a single daily dose. In both hospitals many patients developed polyuria. Multiple regression analyses with sex, age, treatment duration, serum lithium concentration, and treatment regimen as predictor variables showed that the two treatment regimens did not affect the glomerular filtration rate or the proximal reabsorption differently, but that distal water reabsorption was significantly less affected and polyuria less pronounced in the patients given conventional tablets once daily than in those give slow-release tablets twice daily. The authors are divided among themselves as regards the implications of these findings.

Adult↗
PubMed1982

Plasma arginine-vasopressin, renal-concentrating ability and lithium excretion in a group of patients on long-term lithium treatment.

Plasma arginine-vasopressin (AVP) was measured before and after 24 h of a 26-hour renal concentration test in 47 patients treated with lithium for 6-180 months (mean 70 months). In 34 of the patients, plasma AVP was also measured before and after a 2- to 4-hour period of water loading, and in 31 of the patients, creatinine, 125iothalamate, 131I-hippuran and lithium clearances were measured. Plasma AVP values were compared to those obtained in 8 healthy controls. Baseline AVP levels were significantly higher in the lithium-treated patients than in healthy controls. During the period of water deprivation AVP values increased significantly and during oral water loading a significant decrease took place, AVP values still being significantly higher in the lithium-treated patients than in the healthy controls. During oral water loading a slight increase in lithium clearance as well as fractional lithium excretion was seen as compared to values obtained during the last 2 h of a renal concentration test. This study demonstrates that antidiuretic hormone production is neither blocked nor inhibited during lithium treatment. The hypothalamic system reacts on water deprivation as well as on water loading. This study supports the notion that the main lithium-induced renal affection is a vasopressin-resistant impairment of renal concentrating ability.

Adult↗
PubMed1981

Renal side effects of lithium: the importance of the serum lithium level.

Patients given long-term treatment with lithium often develop an impairment of renal water reabsorption which may lead to clinically significant adverse reactions. A convenient measure of this impairment may be obtained using the ratio of urine volume (V) divided by lithium clearance (CLi). When data from a large group of patients were recalculated, this ratio showed a statistically significant correlation with the serum lithium level. This finding supports the suggestion that patients might advantageously be maintained at lower serum levels than those commonly employed.

Absorption↗
PubMed1981

A stable isotope dilution assay for the antiparkinsonian drug benztropine in biological fluids.

A quantitative gas chromatographic-mass spectrometric (GC-MS) assay was developed for the determination of benztropine in human urine and plasma. The assay utilizes selected ion focusing to monitor in a GC effluent a specific fragment ion of benztropine generated by electron-impact ionization. Benztropine-d3 was the internal standard. The assay can measure 5 ng/ml of benztropine/ml with about 6% precision. The curve relating the amounts of benztropine added versus the amounts found over a large range of benztropine concentrations was a straight line with a nearly zero intercept and a slope of 0.98 +/- 0.02. The method was used for the analysis of benztropine in urine and plasma of patients on therapeutic dose of the drug.

Benztropine↗
PubMed1981

Serum lithium concentrations around the clock with different treatment regimens and the diurnal variation of the renal lithium clearance.

The serum lithium concentration was determined around the clock in patients treated with conventional tablets given once daily, in the evening, and in patients treated with slow-release tablets given twice daily, in the morning and in the evening. Curve shapes differed markedly in the two groups, with much wider variation of serum concentrations in the former than in the latter. The data were used to calculate for the two patient groups the ratio of the mean serum lithium concentration over the 24-h day to the serum lithium concentration in blood samples drawn 12 h after the last intake of lithium. Around-the-clock determinations of the patients' renal lithium clearance showed about 20% lower values during the night than during the day.

Bipolar Disorder↗
PubMed1981

Kidney morphology and function in lithium-treated patients.

The findings of morphological changes in the kidneys of some patients given long-term treatment with lithium and indications that lithium intoxications frequently are preceded by alterations in water and electrolyte metabolism have generated new interest in the effect of long-term lithium treatment on kidney structure and function. Today it is not firmly established to which extent renal morphological changes are present in unselected groups of patients given long-term treatment with lithium. Neither is it clear what is the clinical significance of these changes and what are the relative roles played by lithium, concomitant and previous treatment with other psychotropic drugs, previous occurrence of lithium intoxications, and coexistence of somatic illness for their development. Studies on kidney function in long-term lithium-treated patients, however, have revealed that affection of GFR was either moderate or absent indicating that the risk of renal insufficiency and terminal azotemia is remote even when lithium is given for many years. A large number of patients have altered water excretion with polyuria or lowered urine concentrating ability or both. Due to the extra fluid loss these patients are apt to develop dehydration, and they may then be in danger of lithium intoxication. We hypothesize that lithium-induced changes of kidney function may become less frequent and less pronounced if patients are maintained at serum lithium levels somewhat lower (0.5-0.8 mmol/l) than those commonly employed. We recommend careful monitoring of serum lithium levels, regular control of kidney function, and extra caution when physical illness or additional drug treatment may lead to disturbance of fluid and electrolyte balance.

Glomerular Filtration Rate↗
PubMed1980

The analysis of urinary hormonal steroids.

A survey in given of current trends in the assay of urinary hormonal steroids. Both group assay methodology and assays for single urinary steroids are reviewed as are semi-automated and automated procedures and high-resolution and high-capacity techniques, as applied to the profile analysis of urinary steroid hormones.

17-Ketosteroids↗