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Biomedical subjects

M I Lucena

Publications and source records attributed to M I Lucena.

At least 37 records · Page 2Linked to original sources
PubMed1999

Acute liver injury associated with the use of ebrotidine, a new H2-receptor antagonist.

BACKGROUND/AIM: Ebrotidine is a new H2-receptor antagonist marketed in Spain in early 1997 and withdrawn in July 1998. We report 11 cases of acute liver injury related to ebrotidine and submitted to a Regional Registry of Hepatotoxicity between June 1997 and August 1998. METHODS: In all cases a structured protocol was used to ascertain the role of ebrotidine and to exclude other causes (viral, immunologic, metabolic) of liver injury. RESULTS: All patients showed clinical symptoms of acute hepatitis, with a marked increase in aminotransferase activities (ALT values ranging from 15 to 91 times the upper limit of normal). Total bilirubin values were also greatly increased (mean 16 mg/dl), and the liver injury was defined as hepatocellular. Features of hypersensitivity were absent. Liver biopsy was done in three patients. Histopathological examination revealed mainly centrozonal necrosis (two cases) or massive necrosis (one patient). Withdrawal of the drug was followed by a gradual improvement in liver dysfunction, except in one patient who developed fulminant hepatic failure and died. There was a positive response to rechallenge in one patient after an inadvertent drug administration. CONCLUSION: Ebrotidine therapy seems to be associated with severe acute liver injury, and therefore its benefit/risk ratio is unfavorable. The relative rareness and unpredictability of the injury, the lack of dose-relationship and the absence of hallmarks of drug allergy are suggestive of an idiosyncratic metabolic mechanism.

Acute Disease↗
PubMed1998

Variations in blood levels of aminoglycosides related to in vitro anticoagulant usage.

Aminoglycosides (AMG) remain an important therapeutic modality for the treatment of gram-negative infections. Adequate AMG levels have been associated with a lower risk of toxicity. Because AMG levels cannot be predicted with confidence, drug concentrations need to be measured. The authors studied the effect of different anticoagulants on AMG concentrations, which were determined by enzyme immunoanalysis. Blood samples from patients treated with AMG were obtained, and were immediately distributed in five tubes containing EDTA, sodium-citrate, or heparin at concentrations of 5 and 50 U/ml; one serum aliquot was kept as a control. All AMG determinations were performed by the enzyme multiplied immunoassay technique with Cobas-Mira equipment. The average coefficient of variations was < 3%. All samples were run the same day. Analysis of variance for repeated measures was used. Twenty-four patients (21 male and 6 female) with a mean age of 50 years (95% confidence interval = 43 to 58) and mean serum creatinine concentrations of 0.87 to 0.29 +/- Standard Deviation received 89% gentamicin and 11% tobramycin. Peak levels of AMG obtained from plasma collected with sodium citrate or heparin were significantly lower (p < 0.001) than in serum or plasma collected with EDTA. The higher the level of AMG in serum, the greater the discrepancies between drug concentrations measured with different anticoagulants. The anticoagulant used was of critical importance in determining AMG blood levels, which were underestimated when citrate or heparin were present.

Adult↗
PubMed1997

Oral fenoterol versus sustained release theophylline in adult asthmatics.

AIM: The question regarding the minimal effective oral dose of fenoterol remains unanswered. The present study was undertaken to compare the therapeutic effects of sustained release theophylline and a conventional low dose oral fenoterol in patients with asthma. PATIENTS AND METHODS: A double-blind, double-dummy, randomized, 2-phase, cross-over comparison between sustained-release theophylline (SR-T) and oral fenoterol 2.5 mg 3 times daily in 21 patients with stable bronchial asthma (mean age 51 years) was conducted. Each drug was administered for a 2-week period. All patients qualified with a > or = 15% reversibility in forced expiratory volume in 1 second (FEV1) following 200 micrograms of inhaled salbutamol. Spirometric tests and body plethysmography were done at baseline and at the end of each treatment period. Blood was drawn for routine laboratory analysis and serum theophylline concentration. During each treatment period the patient kept a diary of symptoms and the concurrent use of inhaled salbutamol was recorded. RESULTS: During SR-T administration trough serum concentrations were 12.9 (1.5) mg/l mean (+/- SEM). SR-theophylline produced greater maximal changes in all parameters measured: FEV1, forced vital capacity, and specific airway resistance from the pretreatment and fenoterol phase, while fenoterol caused significant changes in none of the test variables. Patients showed an overall preference for SR-T over fenoterol (p < 0.05). CONCLUSIONS: Thus, 2.5 mg of fenoterol at 8-hour intervals did not prove to be an effective alternative to sustained release theophylline for management of patients with asthma. An appropriate dosing schedule for fenoterol needs to be redefined.

Administration, Inhalation↗
PubMed1996

Effect of cyclosporin A on platelet aggregation and thromboxane/prostacyclin balance in a model of extrahepatic cholestasis in the rat.

Cyclosporin A (CsA), a potent immunosuppressor used in organ transplants and autoimmune diseases, is associated with adverse effects in the kidney, liver, and nervous system. This drug was recently shown to stimulate platelet aggregation, to increase thromboxane synthesis, and to decrease vascular prostacyclin synthesis. In experimental cholestasis, thrombocyte function is altered. The present study was designed to assess the effects of CsA on platelet function in extrahepatic biliary obstruction (EBO) in rats. Cyclosporin or its excipient (Cremaphore El, polyethoxylated castor oil) did not modify collagen-induced platelet aggregation. In animals with EBO, platelet aggregation decreased by 50%. The administration of CsA (5 or 10 mg/kg) or Cremaphore El increased aggregation by 163%, 253% and 123% respectively. Thromboxane production increased by 119% after Cremaphore El was administered, but was not significantly modified by CsA. Cholestasis increased thromboxane synthesis by 48.4%, whereas CsA showed a direct dose-dependent effect, and excipient had no significant effect. Excipient inhibited the vascular synthesis of 6-keto-PFG1 alpha by 67.2%, as did 5 mg/kg (56.8%) and 10 mg/kg CsA (27.6%). EBO led to a nonsignificant increase in the vascular synthesis of 6-keto-PFG1 alpha. Cremaphore EI inhibited prostacyclin synthesis by 79%; inhibition by CsA was dose-dependent (31% at 5 mg/kg, 60% at 10 mg/kg). Our findings show that cholestasis enhances the effects of CsA on platelet aggregation and thromboxane/prostacyclin balance. These results may reflect the vascular effects of CsA, which in turn may be enhanced by cholestasis.

Animals↗
PubMed1995

Aminoglycoside-associated nephrotoxicity in extrahepatic obstructive jaundice.

Experimental data demonstrate that biliary obstruction increases renal sensitivity to gentamicin. In the present study the incidence of and risk factors for aminoglycoside nephrotoxicity were prospectively studied in patients with extrahepatic obstructive jaundice. Two hundred and thirty-seven hospitalized adult patients were classified into three groups. Group I consisted of 84 patients with extrahepatic obstructive jaundice, who received aminoglycoside (gentamicin or tobramycin). Group II consisted of 81 patients with extrahepatic obstructive jaundice, who received either antibiotics other than aminoglycoside or no antimicrobial therapy. Group III consisted of 72 noncholestatic patients receiving aminoglycosides for different disorders. Nephrotoxicity developed in 27 patients (32%) in group I vs 9 patients (11%) in group II and 4 patients (5.6%) in group III (p < 0.00001). In group I, a comparison of patients with and without nephrotoxicity revealed significantly higher values in the former for mean serum bilirubin concentration, initial steady-state trough aminoglycoside concentration and estimated half-life. Stepwise multivariate analysis with nephrotoxicity status as the dependent variable determined that the most significant variable for predicting nephrotoxicity was serum total bilirubin level. In extrahepatic cholestasis a high serum bilirubin level is a distinct factor predisposing to aminoglycoside nephrotoxicity.

Aged↗