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At least 73 records · Page 4Linked to original sources
PubMed1978

Possible role of antibody specific for a practolol metabolite in the pathogenesis of oculomucocutaneous syndrome.

The clinical distribution of an antibody to a metabolite of practolol was investigated, particularly in relation to the oculomucocutaneous syndrome. Serum samples were obtained from patients with and without a history of adverse reaction to practolol and two groups of control patients who had never taken the drug. Five patients also participated in a challenge study. The presence of the antibody was found to be related to practolol administration, and antibody activity could be increased by antigenic challenge. The role of this antibody in the pathogenesis of the oculomucocutaneous syndrome remains uncertain. The lesions may be the result of a hitherto unknown type of hypersensitivity response to practolol.

Antibodies↗
PubMed1976

Methyldopa and propranolol or practolol in moderate hypertension.

The effect of a low dose of methyldopa combined with (a) a non-selective and (b) a selective beta-adrenoceptor antagonist was studied in a double-blind crossover trial in 24 carefully selected patients with moderate hypertension (mean initial lying blood pressure 189/117 mm Hg). Each patient received methyldopa 750 mg/day, propranolol 240 mg/day, practolol 600 mg/day, methyldopa 750 mg/day combined with propranolol 240 mg/day, methyldopa 750 mg/day combined with practolol 600 mg/day, and placebo for four weeks each according to a random sequence. After four weeks of therapy the most effective treatment, methyldopa combined with propranolol, reduced lying and standing blood pressures by 36-5/21-4 mm Hg and 44-7/25 mm Hg respectively. Thic combination had similar effects to those of the combination of methyldopa with the cardioselective agent practolol except that it reduced lying diastolic pressure further. The combination was more effective than either treatment alone. No significant differences were found between the effects of propranolol, practolol, or methyldopa at the doses used.

Adult↗
PubMed1975

Antagonism of fenoterol against beta-blocking drugs bunitrolol and practolol in asthmatics.

In 4 X 10 young white male histamine-sensitive asthmatics without bronchitis or emphysema, the antagonism of fenoterol (40 mug) to bunitrolol (2.5 and 5 mg) or practolol (20 and 30 mg) was tested in an open comparative trial. Pulse frequency and several physiological parameters were determined before and after histamine challenge test, after injection of beta-blocking drug and after injection of fenotrolol. All groups were found to be equally sensitive to histamine. Bunitrolol and practolol were found to have no influence on histamine effect. It was also found that bunitrolol in the dosages tested is a much more potent beta-blocking drug in the bronchi compared to practolol in the dosages tested were equivalent. beta-Blockade of practolol (20 or 30 mg) could completely be antagonized by 40 mug fenoterol; this dosage was not sufficient to antagonize 2.5 or 5 mg bunitrolol.

Adolescent↗
PubMed1976

Comparison of the effects of atenolol and practolol on exercise tachycardia in normal subjects.

The relationship between cumulative doses of practolol and atenolol and resultant decreases in exercise tachycardia has been examined in 4 healthy volunteers. Continuous intravenous infusions of practolol (0.4 mg/kg), atenolol (0.12 mg/kg) and saline were administered between 7 and 12 minutes of bicycle exercise. The mean (+/- S.E.M.) heart rate (HR) at 7 min. for practolol (133 +/- 5.1) and atenolol (132 +/- 2.8) were significantly (p less than .01) reduced to 115 +/- 2.3 and 104 +/- 2.9 beats/min. respectively. The pre-infusion HR in the saline study (132 +/- 1.2) was unchanged (133 +/- 4.6) at 12 min. The relationship between the log cumulative dose of each drug and the per cent fall in HR/min was linear for each subject. The log dose-response curve (mean of 4 subjects) for practolol (y = 9.6x + 18.1) was more horizontal than for atenolol (y = 18.4x + 38.6).

Adult↗
PubMed1975

Effects of practolol in combination with terbutaline in the treatment of hypertension and arrhythmias in asthmatic patients.

After a run-in period practolol was given in the dose of 100 mg twice daily to 29 patients with chronic bronchial asthma on the indication hypertension (12) and supraventricular arrhythmia (17). During the run-in period, as well as during the practolol period, a long-acting beta2-stimulator, terbutaline, was given in the dose of 5 mg three times daily. Peak expiratory flow (PEF), heart rate and blood pressure were measured under standardized conditions. No change of the lung function was observed during practolol therapy. Systolic as well as diastolic blood pressure fell significantly. The heart rhythm was normalized in 15 of the arrhythmic subjects. No subjective worsening of the asthmatic symptoms or any other side effects were noted. It is suggested that practolol can be safely used in patients prone to bronchospasm, provided a long-acting beta2-stimulating drug is given concomitantly on the usual indications for beta blockers in acute situations.

Adult↗
PubMed1977

Circulatory responses to laryngoscopy and endotracheal intubation in patients with and without cardiovascular disease. Effect of prophylactic practolol.

The effect of small intravenous doses of practolol (0.2 mg/kg body weight) on the circulatory response to laryngoscopy and endotracheal intubation, when administered with atropine (0.01 mg/kg b.w.) prior to anaesthesia was studied in 39 patients with and without cardiovascular disease. Practolol diminished significantly the rise of mean arterial pressure and pulse rate affected by laryngoscopy and endotracheal intubation when performed under thiopentone-succinylcholine anaesthesia. Arrhythmias were also less frequent through the statistical significance could not be ascertained in this small series. The small practolol dose used had no adverse circulatory effects. It is suggested that the administration of a small prophylactic dose of practolol is useful in preventing the excessive cardiovascular response due to laryngoscopy and endotracheal intubation.

Adult↗
PubMed1981

[Practolol test for adrenergic beta receptor blockade in veterinary electrocardiographic diagnosis].

The receptor theory of the action of catecholamines as well as the synthesis and production of beta-adrenolytics gave new perspectives for the treatment of circulatory diseases and enabled to use the beta-adrenergic blockade in electrocardiographic diagnosis. The aim of this work was to study whether it is possible to modify the oral method of administration used in human beings, into intravenous one, and what an information could be obtained as to actual heart condition after practolol injection. The results can be summarized as follows:--Practolol-Polfa injected intravenously in amounts of 30-50 mg for horse or cow and 3-10 mg for dog in ten minutes deviates the curve evoked by sympathectomy;--after the administration of the drug functional changes of final ventricular complex disappear which is the result of adrenergic system prevalence;--repolarization disturbances observed after the blockade indicate a myocardial defect and later, a partial decrease of changes in T wave shows that a vegetative factor is involved;--increased disturbances of the repolarisation phase after the practolol test indicate of myocardial defect due to compensatory mechanism of adrenergic system in relation to serious hemodynamic disturbances of the heart;--practolol test gives wider possibilities of interpretation, not only from the diagnostic point of view, but therapeutic as well.

Animals↗
PubMed1978

The efficacy of practolol-induced beta1 adrenergic blockade in the canine heart.

The efficacy of adrenergic blockade with practolol was assessed by subjecting 6 adult mongrel dogs in a closed-chest procedure to bolus injections of isoproterenol (0.5 mcg/kg, i.v.) before and after practolol (2.0 mg/kg, i.v.). Following practolol both heart rate and pulse pressure responses were significantly reduced. It is suggested that significant beta1 receptor adrenergic blockade is achieved by practolol.

Animals↗
PubMed1977

Comparative effect of intravenous administration of atenolol and practolol on resting and exercise-evoked increase in heart rate and cardiac work load in normal human subjects.

A comparative study of the intensity and duration of action of intravenously administered single doses of atenolol and practolol on the resting and exercise-evoked increase in heart rate and rate-pressure product was carried out in six normal human subjects. On a weight to weight basis, atenolol was 8 times more potent than practolol. There were only marginal differences in the intensity and duration of action of the two drugs. Atenolol, like practolol, was well-tolerated and no side effects were observed. If found safe on longterm use, atenolol may be a suitable alternative to practolol. The daily administration of atenolol in two divided doses should suffice for therapeutic purposes.

Adult↗
PubMedDate not supplied

Influence of the hemodialysis on the half-life of practolol in patients with severe renal failure.

Practolol, a recent and more selective beta-adrenergic receptor blocking drug, was given orally as a single dose of 200 mg to seven healthy volunteers and to six patients suffering from severe renal impairment and submitted to the long-term hemodialysis program. The plasma drug decay was markedly slowed and the plasma half-life was prolonged sixfold in the uremic patients in comparison to healthy volunteers. Hemodialysis (8 hours) starting 48 hours after drug intake lowered plasma practolol significantly but transiently. The shorter half-life during hemodialysis and the detection of equally high values of practolol in the ultrafiltrates as in the plasma demonstrate that this drug is readily removable from the plasma. However, the ascending slope of the plasma drug concentration curve which appeared following hemodialysis is suggestive of an incomplete drug removal from the body.

Adult↗
PubMedDate not supplied

[Effects of practolol on A-V conduction during atrial stimulation in 50 patients with and without coronary heart disease].

Practolol was injected intravenously at 3 dose levels (5, 15 and 25 mg total dose) in patients with ischemic heart disease and in non-cardiac cases. The influence of practolol on the P-Q interval at rest and at paced rates (atrial stimulation) of 110, 125 and 140 beats/min was studied: only the 15 mg dose produced a significant prolongation of the P-Q interval of normal patients at rest and at paced rates. No significant P-Q changes were found in patients with ischemic heart disease at all dose levels. It is concluded that practolol has no measurable direct effect on A-V conduction and that patients with ischemic heart disease are not more sensitive as regards A-V conduction.

Adolescent↗
PubMed1975

The use of practolol in supraventricular arrhythmias associated with acute illnesses.

Supraventricular arrhythmias complicating acute illnesses were treated with intravenously administered practolol, a cardioselective beta adrenergic blocking agent. Slowing of atrioventricular conduction resulted in rapid control of ventricular rate in 23 of 33 episodes (70 percent) in 31 patients. Profound hypotension developed in two patients, presumably as a result of interference with adrenergic circulatory support. Serum levels from 19 patients showed no correlation with response to therapy and were much lower than levels previously reported necessary for slowing of tachycardias induced by isoproterenol and exercise. Response to practolol was maximum within 15 minutes and was not improved by additional dosage sufficient to raise serum levels. Practolol was a rapidly effective and safe antiarrhythmic agent in situations in which propranolol would be contraindicated and the risk of digitalis toxicity increased; it should be considered a primary drug for initiation of therapy for supraventricular tachyarrhythmias.

Acute Disease↗
PubMed1976

Comparison of respiratory and cardiovascular effects of isoproterenol, propranolol, and practolol in asthmatic and normal subjects.

Pulmonary functions, by means of FEV1, FVC, and airway resistance, and cardiovascular responses, i.e., ECG, blood pressure, and pulse contour, were measured in 10 control and 15 symptom-free asthmatic subjects during and after the infusions of isoproterenol, with or without previous administration of propranolol or practolol. Bronchial sensitivity to methacholine and response to isoproterenol after methacholine were also measured. Bronchial sensitivity to methacholine challenge was markedly enhanced by propranolol and the effect of isoproterenol infusion on the pulmonary function was also significantly diminished, whereas practolol did not reveal any effect on bronchial sensitivity to methacholine or isoproterenol. The above changes were much more profound in symptom-free asthmatic subjects than in control subjects. The results suggest that practolol does not significantly affect the beta-2 bronchial receptors, is safe to use in asthmatic subjects, and is consistent with an abnormality of these receptors in bronchial asthma.

Adolescent↗
PubMed1979

Immunological aspects of practolol toxicity.

It is unfortunate that there is conflicting immunological data relating to the practolol syndrome. It has not been established if "practolol patients" have some altered T cell function. The work of Behan et al. (1976) strongly supports this interpretation but other groups have not come to the same conclusion. The role of the antibody specific for a practolol metabolite needs to be determined. In practice this is going to be very difficult to do; the drug is no longer used and patients, for obvious reaons, are unwilling to take part in clinical experiments. It is likely that the nature of the metabolite will eventiually be defined and it would be a significant step forward if it could be shown that the antigenic determinant was not formed by other structurally related beta-blocking drugs. Meanwhile the stimulus to further research must be to produce an animal model system, but, for various political and economic reasons, support for such a research effort is difficult to justify.

Animals↗
PubMed1983

Influence of propranolol, pindolol, practolol and talinolol on arachidonic acid (AA)- and U-46619-induced aggregation and on AA-induced thromboxane A2 formation in platelets.

The effects of four beta-adrenoceptor blocking agents on arachidonic acid (AA)-induced platelet aggregation and thromboxane (TX) formation in human and rabbit platelet-rich plasma (PRP) as well as their influence on prostaglandin endoperoxide analogue (U-46619)-induced aggregation in human PRP were studied. The potency against AA-induced aggregation decreased in the following sequence: pindolol greater than propranolol greater than talinolol greater than practolol (without effect). Pindolol (0.1-1.0 mmol/l) inhibited both AA-induced aggregation and TX formation. The cyclooxygenase activity in ram seminal vesicle microsomes was suppressed by both pindolol isomers. Propranolol was without effect on the cyclooxygenase. This supports the assumption that the inhibitory activity of pindolol on AA-induced platelet aggregation is mediated by its inhibiting effect on platelet cyclooxygenase as the first step of the TX formation. Propranolol (IC50:0.2 mmol/l), talinolol (IC50:0.7 mmol/l) and pindolol (IC50:1.3 mmol/l) inhibited the U-46619-induced aggregation, whereas practolol remained without effect. The spectrum of the reported data with propranolol, talinolol and practolol may be assumed to allow the correlation of the results to both the membrane stabilizing effects and to lipophilicity of the drugs.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1977

Practolol peritonitis.

Barium examination of the small bowel revealed fixation, dilation, separation of bowel loops and delayed small intestinal transit in nine patients with practolol induced peritonitis. The diagnosis may be first suggested by this examination, and a history of prolonged therapy with beta-blocking agents should be sought in patients showing these changes where no other cause for them can be found. Symptoms may develop up to a year following cessation of therapy so that further cases may still come to light despite the withdrawal of practolol for long-term use. Small bowel barium examination is indicated in patients who have received practolol therapy and who develop suspicious alimentary symptoms.

Aged↗
PubMed1977

Frequency of eye complaints and rashes among patients receiving practolol and propranolol.

Among 71 patients treated with practolol by general practitioners, eye complaints were recorded in the case-notes of 14 (20%) during treatment, compared with 4 (6%) during equal periods before the drug was prescribed. Half the patients with eye complaints also had a rash while receiving practolol. These findings, which were not due to greater numbers of attendances during treatment nor to awareness of the hazards of the drug, suggest that mild eye complaints were relatively common among patients treated with practolol. Among 246 patients treated with propranolol, the numbers with eye complaints before and during treatment were similar, although there was a significant excess of patients with both an eye complaint and a rash during treatment.

Adult↗
PubMed1990

Synthesis and beta-adrenergic antagonist activity of stereoisomeric practolol and propranolol derivatives.

A series of stereoisomeric practolol and propranolol derivatives has been synthesized in which the N-isopropyl group of the drug was replaced by an asymmetric heptanoic acid terminated by a substituted p-toluidide or p-(trifluoromethyl)anilide. The asymmetric epoxide, 3-(p-acetamidophenoxy)-1,2-epoxypropane, was allowed to react with a preformed enantiomeric 6-aminoheptanoic acid amide to yield the stereoisomeric practolol congener derivatives. An asymmetric drug precursor epoxide was prepared from p-acetamidophenol and enantiomeric 3-(tosyloxy)-1,2-epoxypropane 6-aminoheptanoic acid amides were allowed to react with one of the enantiomers of 3-(1-naphthyloxy)-1,2-epoxypropane. This drug precursor epoxide was prepared either by combining 1-naphthol with enantiomeric 3-(tosyloxy)-1,2-epoxypropane (the Sharpless epoxide) or by combining 1-naphthol with enantiomeric 3-(tosyloxy)-1,2-propanediol followed by epoxidation. Pharmacological studies carried out for the practolol derivatives demonstrated a significant dependence of enhanced potency and tissue/subreceptor specificity on both the configuration of the drug asymmetric carbon and the configuration of the spacer asymmetric carbon. The compounds containing the S configuration at the drug asymmetric center and the R configuration at the spacer asymmetric carbon exhibited an increase in potency over the other stereoisomeric congener derivatives and the progenitor drug. For the propranolol congener derivatives, a large decrease in potency was observed for all of the stereoisomers over the progenitor drug. The propranolol stereoisomers containing the S configuration at the drug asymmetric center were more active than those containing the R configuration at that center.

Adipose Tissue↗