摘要:

A review of the literature describing the interaction of digoxin and spironolactone is presented. Two mechanisms of possible interaction are discussed. Spironolactone and its metabolites may interfere with digoxin radioimmunoassay or alter the pharmacokinetics of digoxin. The occurrence of either or both of these processes may make interpretation of serum digoxin levels difficult.

ISSN:0163-4356    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Cefoperazone is a new piperazine cephalosporin derivative which has a broad antibacterial activity against aerobic and anaerobic gram-positive and gram-negative cocci and bacilli, includingPseudomonas aeruginosa.In studies of the intramuscular (i.m.) administration of cefoperazone at doses of 0.25, 0.5, and 1 g, mean peak serum concentrations were 22, 33, and 67 μg/ml at 1 hr. At 8 hr, serum levels were 2.1, 4.8, and 5.6μg/ml, respectively, for the three doses. The mean half-life after intramuscular injection was 108–154 min. Urinary recovery ranged from 14 to 18% of an administered dose. Intravenous (i.v.) administration of cefoperazone by rapid (3–5 min) infusion produced serum levels at 15 min of 76, 156, and 244 μg/ml after doses of 0.5, 1, and 2 g, respectively. Concentrations of cefoperazone at 8 hr were 2.4, 6.5, and 11.8 μg/ml after these respective doses. Serum half-life was 115–120 min and urinary recovery, 29–33%. Levels determined at 5 min after bolus injection were 200 μg/ml for 1 g, 275 μg/ml for 2 g and 518 μg/ml for 3 g. Intravenous infusion studies of cefoperazone in which 2 g of the drug has been infused over 15, 30, or 120 min have yielded levels of 250–260 μg/ml. At 12 hr, levels of 1–2 μg/ml were still present. The half-life found in these studies ranged from 1.6 to 2.38 hr Urinary recovery was 25–30%. Serum clearances have been 80–90 ml/min and renal clearances, 18–30 ml/min. The apparent volume of distribution of the compound has ranged from 10 to 16 liters. Comparative studies have shown that cefoperazone produced higher serum levels than cefazolin, cefamandole, cefotaxime, and moxalactam. Biliary concentrations exceed 400 μg/ml and are two to four times the levels found with cefazolin or cefamandole. In the presence of renal failure there is a minimal increase in serum half-life; but in the presence of biliary obstruction, serum half-life may reach 11 hr, depending on the degree of biliary obstruction. In the presence of biliary obstruction, the drug is 90% removed from the body by renal excretion.

ISSN:0163-4356    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Plasma and urine concentrations of creatinine, sulphamethoxazole and its metaboliteN4-acetylsulphamethoxazole were measured in patients with varying degrees of kidney impairment. The plasma elimination half-life of sulphamethoxazole is not influenced by the kidney function, while the half-life of the metabolite is fully dependent on the kidney function. The renal clearances of the metabolite and that of the parent compound under alkaline urine conditions are linearly related to the creatinine clearance. Kidney impairment affects only the renal clearance of the metabolite, whereas sulphamethoxazole is metabolized (acetylated) independently of kidney function.

ISSN:0163-4356    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Serum digoxin concentration (SDC) was compared with clinical and ancillary predictors as a guide to adjustment of digoxin dose and as a test for digitalis toxicity in a total of 76 hospitalized patients during a period of 9 months. The mean SDC (3.6 ± 2.5 nmoles/liter) associated with unexpected discontinuation of therapy was significantly higher (p< 0.001) than that (1.1 ± 0.6 nmoles/liter) associated with unaltered digoxin dose, while the mean SDC (0.6 ± 0.4 nmole/liter) associated with unexpected dose increase was significantly lower (p< 0.05). There was no significant association between other pharmacokinetic or pharmacodynamic predictors and therapeutic intention. There was a 13% incidence of confirmed digitalis intoxication. The mean SDC (3.6 ± 1.9 nmoles/liter) of patients presenting and confirmed as digitalis toxic was significantly higher (p< 0.001) than that (1.4 ± 0.6 nmoles/liter) involving a situation in which digitalis toxicity could not initially be excluded by other means. The predictive value of an SDC ≥ 2.6 nmoles/liter for toxicity was 80%, and its efficiency for diagnosing both toxicity and nontoxicity was 95%. The SDC was thus shown to be a valid test of digitalis toxicity and to provide extraordinary information enabling the clinician to modulate digoxin therapy precisely.

ISSN:0163-4356    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The relationships between serum and saliva concentrations were evaluated in 18 patients after single doses of three theophylline preparations. Simultaneous multiple saliva and serum samples were obtained after theophylline ingestion and were analyzed for theophylline content by the modified Schack and Waxier spectrophotometric method. Significant variability was observed in the data for those saliva/serum ratio sets obtained within 30 min of dosage. The mean correlation coefficient for saliva/serum sample sets obtained at and after 30 min was 0.86. Pearson product moment correlation coefficients determined for saliva/serum ratios at 2,4,6, and 8 hr ranged from 0.84 to 0.89, leaving 26% of the variance unexplained. Serum concentrations were calculated from a randomly selected saliva/serum ratio for each patient. Predicted serum concentrations were ± 2 μg/ml of measured concentrations in only 143 of the 196 determinations (73%). Therefore, the use of saliva concentrations to predict serum values has substantial error in specific patients and may lead to incorrect dosage adjustments.

ISSN:0163-4356    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Levels of the anticonvulsant drugs phenobarbitone, phenytoin, carbamazepine, and primidone were measured in the plasma and saliva of 202 epileptic children (5 months-18 years old). Gas-liquid chromatography (GLC) and EMIT® immunoassay were used to analyse the samples. Saliva to plasma ratios were as follows (means ± SD). phenobarbitone: GLC, 0.30 ± 0.05 (r= 0.94); EMIT, 0.31 ± 0.06 (r= 0.92); phenytoin: GLC, 0.11 ± 0.02 (r= 0.94); EMIT, 0.12 ± 0.04 (r= 0.86); carbamazepine: GLC, 0.26 ± 0.05 (r= 0.91); EMIT, 0.25 ± 0.06 (r= 0.83); primidone: GLC, 1.04 ± 0.24 (r= 0.94); EMIT, 0.95 ± 0.20 (r= 0.98). There was good agreement between the two methods, and the ratios obtained are the same as those found for adults.

ISSN:0163-4356    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

A fluoroimmunoassay for the determination of serum or plasma levels of propranolol was developed using antibodies to propranolol coupled to magnetizable solid-phase particles and fluorescein-labeled propranolol as tracer. The method was sufficiently sensitive, precise, and specific for application to routine monitoring of propranolol therapy, and gave good correlation (r = 0.99) with a widely used ultraviolet fluorometric method in the assay of patients' specimens. The fluoroimmunoassay involves the same instrumentation as the fluorometric assay and has practical advantages, including greater sensitivity (only 100 μl of sample required), avoidance of an extraction step, and visible-wavelength fluorometry, which permits the use of disposable plastic apparatus throughout the entire procedure.

ISSN:0163-4356    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Tobramycin usage, as for most aminoglycoside antibiotic usage, may require careful monitoring to avoid irreversible toxicity. Several methods for tobramycin quantitation are available. The purpose of this study was to evaluate the performance of solid-phase immunofluorescence as an alternative. Tobramycin was quantitated in the sera of 81 patients by radioimmunoassay and solid-phase immunofluorescence. No statistically significant or medically important difference was demonstrated (bias, 0.006 μ/ml,t=0.09,s=1.02,r= 0.97). Within-run and run-to-run precision for the two methods were comparable. Interference by gentamicin could not be demonstrated. Solid-phase immunofluorescence may be an acceptable alternative method for tobramycin quantitation in some laboratories.

ISSN:0163-4356    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

A rapid microprocedure for the liquid chromatographic analysis of thiopentone in plasma is described. Reversed-phase liquid chromatography was performed on a microparticulate C18column using as a mixture of 60% methanol/40% water as mobile phase and ultraviolet detection (290 nm). The method used carbamazepine as internal standard and ethyl acetate as extraction solvent. The analytical recovery was 95%; the reproducibility, 6.5%; and the sensitivity limit of detection, 0.2 mg/liter. The method has been used in preliminary studies to determine the plasma concentrations in patients receiving thiopentone by the intravenous route. A method using direct injection is described.

ISSN:0163-4356    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Lidocaine is widely used in antiarrhythmic therapy, and the need to monitor the drug concentration in the blood of patients receiving lidocaine is well established. We have developed a new assay for lidocaine designed for the routine clinical therapeutic drug monitoring laboratory. A 100-μl aliquot of blood plasma is treated with 50 μl of internal standard solution and the mixture alkalinized. The drug and internal standard are extracted with toluene and analyzed by nitrogen-detection gas-liquid chromatography. A single extraction is used, and no solvent evaporation is required, resulting in a simple and rapid procedure. Using the single-point standard, the within-day coefficient of variation (CV) was 6.4%, while the between-day CV was 7.4%. Monoethylgly-cinexylidide, the major plasma metabolite of lidocaine, and several drugs potentially present in patients receiving lidocaine were shown not to interfere. The procedure has significant advantages over previously published similar methods.

ISSN:0163-4356    

出版商:OVID    

年代:1981

数据来源: OVID