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Biomedical subjects

B Sádaba

Publications and source records attributed to B Sádaba.

At least 19 recordsLinked to original sources

[Monitoring and secondary effects of immunosuppressants in the transplant].

The success of organ transplants and their consideration as a clearly established treatment in some indications is due to the development of immunosuppressant drugs. While it was not the first of the drugs to be employed, the introduction of cyclosporin in the 1980s in immunosuppressant treatment made possible an increase in the number of transplants and the success of this practice. From then onwards, immunosuppression has been based on the use of a combination of drugs, initially cyclosporin, corticoids and azathioprine. In recent years new drugs have been introduced that have opened up the possibilities of treatment. But many pending questions remain, due to the toxicity associated with their use and the possibility of interaction with other drugs, which complicates their use and can compromise the prognoses of these patients. Calcineurin inhibitors and mTOR are the drugs involved with greater frequency in interactions with other drugs, which makes it necessary to anticipate this possibility when the concomitant medication is changed.

Biological Availability↗

Clinical relevance of sirolimus drug interactions in transplant patients.

Sirolimus, a new immunosuppressant drug; is metabolized by cytochrome P450 3A4 (CYP3A4) and is a substrate of the P-glycoprotein drug efflux pump. The CYP3A4/P-glycoprotein system is mainly localized in the liver and intestine. It is responsible for the severe first pass metabolism of sirolimus with a low bioavailability. Drugs like voriconazole, itraconazole, fluconazole, and erytrhomycin may decrease the metabolic activity of this enzymatic system. This report documents in five patients that coadministration of these antimicrobials with sirolimus increases the blood concentrations of the immunosuppressant. The dose-normalized trough blood concentration showed a mean increase of sevenfold with the coadministration of these drugs. It is essential to monitor the blood sirolimus concentrations and to adjust the sirolimus doses before and after coadministration of these drugs.

Aged↗

Relationship between pharmacokinetics and pharmacodynamics of beta-lactams and outcome.

The in-vitro susceptibility of an organism and the pharmacokinetics of an antimicrobial agent are two basic factors on which the choice of standardised treatment regimens is based. However, the inter-individual variability of these factors, which modifies the exposure of bacteria to an antibiotic in terms of time and quantity, is not usually taken into account. In 87 patients treated with beta-lactams (ceftriaxone, cefepime or piperacillin), the probability of failure was greater when the infectious process was located in tissues with barriers to the distribution of beta-lactams. Mean MICs of piperacillin and cefepime, but not ceftriaxone, were below the breakpoints in cases of both recovery and failure, but organisms isolated from patients with a poor outcome had higher MICs. Therefore, the use of breakpoints to determine the susceptibility of microorganisms was not satisfactory in predicting the outcome for a large number of patients. If MICs are determined and plasma concentrations are monitored, dosages can be adjusted according to these parameters, thereby allowing antibiotic treatment to be individualised.

Adult↗

Development of a chromatographic method for the determination of saquinavir in plasma samples of HIV patients.

A simple, sensitive and reproducible high-performance liquid chromatographic method for detecting and quantifying saquinavir in human plasma is described. Verapamil was used as internal standard. The method employes a single liquid-liquid extraction step with tert-butil methyl ether followed by chromatography on a Lichrospher 60 Select B C8 reversed-phase column. Ultraviolet detection was used to identify the compounds of interest. The quantitation limit of saquinavir was 1 ng/mL and only 0.5 mL of plasma sample was required for the determination. The average saquinavir recoveries over a concentration range of 2.5-500 ng/mL ranged from 86 to 95%. Precision and accuracy did not exceed 5%.

Calibration↗

Rapid high-performance liquid chromatographic determination of cefepime in human plasma.

A simple, rapid and reproducible high-performance liquid chromatographic method for the quantitative determination of cefepime in human plasma was developed. Ceftazidime was used as internal standard. Chromatography was performed on a reversed-phase encapped column (Hypersil BDS C18). The samples, after protein precipitation, were eluted with a mobile phase of acetonitrile-acetate buffer, pH 4 (2.8:97.2, v/v). The detection wavelength was 254 nm. The limit of quantitation of cefepime was 0.5 microgram/mL and only 0.5 mL of plasma sample was required for the determination. The average cefepime recoveries over a concentration range of 0.5-500 micrograms/mL ranged from 98 to 104%. Precision and accuracy did not exceed 5%.

Cefepime↗

Concurrent clarithromycin and cyclosporin A treatment.

Although macrolides have been associated with significant pharmacokinetic interactions, clarithromycin is considered to have a low interaction capacity. In this study, six transplant recipients treated with cyclosporin A also received clarithromycin. In all patients, the dose of cyclosporin A had to be reduced by a mean of 33% per day depending on the macrolide dose. Normalization of the dosage parameters began on the fourth day after stopping clarithromycin treatment. Co-administration of cyclosporin A and clarithromycin may lead to increases in whole blood cyclosporin levels, and appropriate dose reductions should be considered.

Anti-Bacterial Agents↗

[Clinical pharmacology and indications of meropenem in severe pediatric infection].

The choice of an antibiotic for the treatment of a serious paediatric infection is generally a difficult problem. The arrival of Carbapenem resulted an important advance in the field of medicine due to its broad-spectrum, low incidence of resistances and good safety profile. Among Carbapenems, Meropenem introduction represents a progress because of its pharmacokinetics characteristics and blood-brain barrier penetration. Meropenem dosage depends on the patient weight, and the way of administration is potentially easier. Meropenem has been compared with the most used paediatric antimicrobial in controlled and randomised clinical trials, showing a high efficacy in the treatment of several infections (respiratory, urinary, intraabdominal, dermatological, septicemia) and in neutropenic and cystic fibrosis patients aged between one month and twelve years old. Meropenem is specially useful in the bacterial meningitis treatment because it penetrates into the cerebrospinal fluid of patients with inflamed meninges and reaches therapeutic concentrations, and because appearance of seizures is low. Adverse reactions produced by Meropenem show a poor incidence and its severity is usually mild. With regard to this characteristics, it can be concluded that Meropenem is an antimicrobial which efficacy and safety profiles guarantee its use in the treatment of severe paediatric infections.

Bacterial Infections↗

[Trovafloxacin].

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Animals↗

[Losartan].

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Abnormalities, Drug-Induced↗

[Levofloxacin].

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Adolescent↗

[Irbesartan].

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Angiotensin II↗