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Biomedical subjects

B Flouvat

Publications and source records attributed to B Flouvat.

At least 73 records · Page 4Linked to original sources
PubMed1981

Pharmacokinetics and bioavailability of diacetolol, the main metabolite of acebutolol.

The pharmacokinetics and bioavailability of diacetolol, the principal metabolite of acebutolol, were studied in 6 healthy subjects. Plasma concentrations were determined following a single intravenous injection of diacetolol 100 mg and three oral doses of diacetolol 100, 400 and 800 mg, in random order. The average oral bioavailability of diacetolol was F: 0.302 +/- 0.052 (100 mg), 0.363 +/- 0.052 (400 mg) and 0.426 +/- 0.068 (800 mg); the differences are not significant. The mean plasma half-life of the terminal phase, 7.94 +/- 0.26 h after intravenous administration, was significantly higher than after oral administration 12.27 +/- 1.00 h (100 mg), 12.82 +/- 1.59 h (400 mg) and 13.05 +/- 13.05 +/- 1.22 h (800 mg) (p less than 0.02 to 0.05); the mean urine half-lives of the terminal phase were not significantly different. Renal clearance of diacetolol 10.2 +/- 0.81 . h-1 represented about wo-thirds of total body clearance 15.9 +/- 1.21 . h-1. The results suggest either a first-pass effect or incomplete absorption of diacetolol after oral administration.

Acebutolol↗
PubMed1981

The efficacy of caffeine in the treatment of recurrent idiopathic apnea in premature infants.

This prospective controlled study was aimed at evaluating the efficacy of caffeine in treating recurrent idiopathic apnea in the premature infant. Eighteen preterm infants (29 to 35 weeks' gestation) were studied. Recordings during the first 24 hours and on the fifth day of caffeine treatment showed a significant decrease of severe apnea (P less than 0.01) and of mild apnea (P less than 0.001) in the treated group (group 1) as compared with the control group (group II). No treatment of apnea other than caffeine was required in group I, whereas six neonates in group II had such severe and frequent apneic episodes for more than 48 hours that withholding additional treatment was believed to be unethical. No undesirable side effects of caffeine treatment were observed.

Apnea↗
PubMed1981

[Clinical pharmacology of prazosin in arterial hypertension with chronic renal insufficiency].

The pharmacokinetics of prazosin were studied in 10 patients (7 male and 3 female, Group I) with permanent hypertension and chronic renal failure (serum creatinine 40,5 +/- 5,9 mg/l) and in 10 normal subjects (10 male, Group II). Each patient received a single oral dose of 2 mg of prazosin; serum levels were studied at regular intervals over a ten hour period by spectrofluorometry Clinostatic blood pressure was measured with a mercury manometer in the patients in Group I. The rate of absorption of prazosin was identical in the two groups (t max: I,3 +/- 0,2 h and I,6 +/- 0,4 h). Maximal serum concentrations were significantly higher in Group I (33,5 +/- 3,7 microgram/1 compared to 22,0 +/- 2.5 microgram/l, p less than 0,02) as was the surface under the serum concentration curve plotted against time (206,I +/- 31.I microgram.h.l-1 compared to 99,9 +/- 12,3 microgram.h.l-1, p less than 0,01). Prazosin induced a significant fall in systolic and diastolic blood pressure (-19% and -23% respectively, p less than 0.001) in Group I, 90 minutes after administration, associated with a moderate rise in heart rate (+16%, p less than 0.01). The variation of blood pressure induced by prazosin correlated closely with its serum concentration (p less than 0.001). These results suggest that the bioavailability of prazosin is significantly higher in chronic renal failure and that a reduction of the daily dose should be envisaged in these patients on long-term therapy.

Adult↗
PubMed1981

[Determination of plasma concentrations of anti-arrhythmia agents].

The measurements of the plasma concentrations of antiarrhythmic drugs is useful both for studying the pharmacokinetics and bio-availability of a drug, and for assessing the relationship between pharmacological activity and plasma levels in clinical practice so that dosages may be adapted to obtain optimal efficacity in each individual patient and to avoid side-effects caused by drugs with low therapeutic indices. Many methods are available, including spectrophotometry, spectrofluorometry, gas chromatography, liquid chromatography and immuno-enzymology. The practicability, sensitivity and specificity of these techniques are compared with respect to their objectives. Particular attention is paid to the principal antiarrhythmic agents with fairly well defined zones of efficacity: procainamide, quinidine, disopyramide, propranolol, lignocaine and mexiletine.

Anti-Arrhythmia Agents↗
PubMed1980

Pharmacokinetics of atenolol in patients with terminal renal failure and influence of haemodialysis.

1 The pharmacokinetics of atenolol, after 200 mg orally, were studied in 18 patients with terminal renal insufficiency (creatinine clearance less than 5 ml/min), of whom twelve were being treated by chronic dialysis. 2 The peak plasma level, 1.59 +/- 0.43 mg/l, was reached in 4.7 +/- 2.1 h. 3 Without dialysis treatment, the apparent plasma half-life of atenolol was greatly increased (73.4 +/- 28.8 /). During dialysis, it dropped to 7.5 +/- 3.7 h but returned to 51.2 +/- 17.3 h after dialysis. The plasma atenolol plot was a rising slope for a few hours after the end of dialysis. 4 Renal clearance of atenolol was very low (4.6 +/- 1.5 ml/min). 5 Plasma clearance during dialysis was 42.6 +/- 21.3 ml/min for a mean blood flow-rate of 236 +/- 25 ml/min through a cuprophane membrane dialyser. 6 These results suggest that dosage should be modified for these patients.

Adult↗
PubMed1979

[Average steady-state plasma levels with slow release quinidine preparations].

Arabogalactane sulphate of quinidine (AGSQ) is a slow release preparation of quinidine. The aim of this study was to compare the plasma levels of quinidine obtained by different preparations of AGSQ (AGSQ I, II and III) and to determine which was best suited to therapeutics. The "in vitro" study showed different amounts of quinidine liberated in 6 hours, 34% with AGSQ I, 58% with AGSQ II and 100% with AGSQ III. The plasma quinidine levels were studied after administration of a dose corresponding to 330 mg quinidine base, morning and evening for 7 consecutive days to 27 hospitalised patients; 7 received AGSQ I, 11 received AGSQ II 5, received AGSQ III and 4 quinidine sulphate. The delay in reaching a steady state was 24 hours for the quinidine sulphate 36 hours for AGSQ I, 48 hours for AGSQ II and 60 hours for AGSQ III. The average plasma level on the 7th day (Cee) was 2.74 +/- 0.71 microgram/ml, 2.62 +/- 0.74 microgram/ml and 3.29 +/- 0.72 microgram/ml respectively. The plasma quinidine levels were maintained between toxic and therapeutic levels (3,5 and 1,7 microgram/ml) only with AGSQ II by suppressing the peak observed 1 hour administration of quinidine sulphate. An excellent correlation (r = 0,984) was observed between the plasma quinidine 6 hours after ingestion and the Cee. A blood test during the steady state, 6 hours after ingestion of the drug, is useful in adjusting the dosage. These results suggest that AGSQ II is the preparation best suited for therapeutic usage although it does not give the best relative bioavailability of the drug.

Delayed-Action Preparations↗
PubMed1978

[Spectrofluorimetric estimation in biological fluids of a new beta-blockader: atenolol. Application to its pharmacokinetic study (author's transl)].

The authors describe a simple method of fluorimetric estimation of atenolol, applicable to blood and urine, sufficiently sensitive to permit a pharmacokinetic study. After administration of a dose of 200 mg by the oral route to hypertensive subjects, one may observe a maximal plasma concentration 3 hours after the dose average value 3.91 +/- 0.71 mumol/l (1.04 +/- 0.19 mg/l). The apparent half life of elimination of phase beta is 14.1 +/- 4.9 h, values comparable with those calculated from urinary data 14.6 +/- 2.0 h. The renal clearance was 140 +/- 32 ml/min; 54 +/- 14% of the administered dose are excreted in the urine. After administration by the venous route, urinary excretion represents 96% of the dose administered.

Adult↗
PubMed1975

[Study of acebutolol dialysis and pharmacokinetic data in patients with renal insufficiency undergoing hemodialysis].

The dialysance of acebutolol, in vitro, has been found to be equal to 87 ml/mn for a blood flow of 200 ml/mn through an artificial kidney; at the same flow rate, that of urea is 136 ml/mn. In subjects with normal renal function, half-life of acebutolol in plasma, after oral administration, is 4.4 +/- 0.6 h; in haemodialysed patients with renal failure, it is very increased; during haemodialysis, it is near normal (mean: 5.9 h in 4 subjects). Authors discuss the meaning of acebutolol dialysance, in vivo, considering a possible protein binding of this drug.

Acebutolol↗
PubMed1975

[Spectrofluorometric determination of a new beta-blocking agent, acebutolol in blood and urine].

The authors describe a simple method of spectrofluorimetric estimation of acebutolol, applicable to blood and urine, sufficiently sensitive to obtain therapeutic concentrations. After administration of a 200 mg dose by mouth, one may observe a maximal plasma concentration 3 hours later, with average values of 1.02 +/- 0.20 mg/liter. The principle of the estimation is based on acid hydrolysis of the product, then condensation of the liberated amine with nitroso-1 naphtol-2 to give a fluorescent derivative (stimulation 460 nm, emission 545 nm).

Acebutolol↗