Effects of dexibuprofen on platelet function in humans: comparison with low-dose aspirin.

BACKGROUND: The aim of the current study is to evaluate the antiplatelet effect of dexibuprofen in healthy volunteers in comparison with low-dose aspirin. METHODS: Healthy volunteers (n = 12) were treated in a crossover manner with 100 mg daily aspirin or with 800 mg daily dexibuprofen. Blood samples were obtained within 24 h; 3, 7, and 14 days after repeated doses; and 24 h after the last dose. In each sample, the authors measured platelet aggregation, thromboxane B2, 6-keto-prostaglandin F1alpha, and nitric oxide. RESULTS: The antiplatelet effect of dexibuprofen (maximal inhibition of aggregation was 48-55% for adenosine diphosphate and 90-95% for collagen and arachidonic acid) was equal to the effect of aspirin. The main difference between the two drugs was in the degree of recovery of platelet function. The effect of aspirin persisted for 24 h after the last dose (remaining inhibition 50%, respect to the pretreatment value), whereas platelet aggregation had returned to baseline pretreatment values within 24 h after dexibuprofen was stopped. CONCLUSIONS: Both aspirin and dexibuprofen inhibited platelet function with a similar intensity, but dexibuprofen exerted a reversible effect for 24 h after the last dose.

The administration of N-acetylcysteine causes a decrease in prothrombin time in patients with paracetamol overdose but without evidence of liver impairment.

OBJECTIVE: To explore the effect of intravenous N-acetylcysteine (NAC) on the prothrombin time (PT) in patients with paracetamol overdose and persistent normal liver profile. MATERIALS AND METHODS: This retrospective case series study examined all admissions with a diagnosis of paracetamol poisoning in a tertiary hospital between 1989 and 2002. Patients were included if they had ever received NAC infusion, had no biochemical evidence of liver damage, and had more than two measurements of PT. Patients who had also ingested other drugs were excluded. RESULTS: Of 65 admissions wtih paracetamol poisoning, 18 patients (10 men) met the inclusion criteria. The median age was 29 years, and the median quantity of paracetamol ingested was 186 mg/kg. The mean number of PT measurements per patient was 4.8. The baseline PT (as a percentage) 8.6 h after paracetamol ingestion was 89.6%. During NAC infusion the PT fell in all patients (range, 4.8-53.4% relative to baseline; P < 0.0001) at 14 h. The PT was less than 60% in 28% of the patients. Eight hours after the initiation of NAC there was a 16% fall in PT (range, 4.3-34%; P < 0.0001). At the end of NAC infusion all PTs returned to values close to baseline. Nine patients were hospitalized. CONCLUSIONS: In patients with paracetamol overdose without evidence of liver damage a marked decrease in PT often occurs, which seems to be due to the overload of NAC infused at the beginning of treatment. This particular feature should be noted in clinical practice guidelines as a potentially misleading indicator of the development of severe liver dysfunction.

HLA class II genotype influences the type of liver injury in drug-induced idiosyncratic liver disease.

Drug-induced idiosyncratic liver disease (DIILD) depends largely on host susceptibility factors. Small studies support the genetic influence of human leukocyte antigen (HLA) class II molecules on the predisposition to DIILD. We sought associations between HLA-DRB and -DQB alleles and DIILD considered collectively or according to the biochemical expression of liver damage. We studied a total of 140 patients with a definitive or probable diagnosis of DIILD, as assessed with the Council for International Organizations of Medical Sciences scale, with 635 volunteer bone marrow and blood donors serving as controls. HLA-DRB1* and -DQB1* genotyping was performed by hybridization with sequence-specific oligonucleotides after genomic amplification. The group with DIILD did not differ from control subjects with regard to the distribution of HLA-DRB and -DQB antigens. The frequencies of alleles DRB1*15 (35.4% vs. 18.6% of controls; P =.002; odds ratio [OR] 2.31) and DQB1*06 (61.5% vs. 40.8%; P =.001; OR 2.32) were significantly increased in patients with the cholestatic/mixed type of liver damage in comparison to healthy subjects. By contrast, frequencies of alleles DRB1*07 (16.9% vs. 35.4%; P =.003; OR 0.37) and DQB1*02 (32.3% vs. 55.8%; P =.0003; OR 0.39) were significantly decreased. In conclusion, there is no association between any specific HLA allele and the propensity to develop DIILD. However, the genetic influence associated with HLA class II alleles appears to play a role in the biochemical expression of liver injury in cholestatic/mixed hepatotoxicity and may explain why a given drug may cause different patterns of liver damage.

Pharmacological approach to diabetic retinopathy.

Diabetic retinopathy is the most frequent cause of legal blindness in the population of 30-to-70-year olds. Whether retinopathy appears or not depends mainly on the duration of the disease and the degree of metabolic control the patient maintains. High blood glucose values lead to important changes in cellular metabolism and the main effects of these alterations are endothelial dysfunction that sets in motion the morphological process of diabetic retinopathy. The biochemical lesions caused by prolonged hyperglycemia can be positively influenced, but usually not normalized, pharmacologically with some groups of drugs, which are now under development. This makes tight control of glycemia a key measure in preventing the onset or progression of diabetic retinopathy, together with an effective program of ophthalmologic detection and follow-up in patients with diabetes. Regarding the role of endothelial dysfunction, antiplatelet drugs have been shown to slow some aspects of the evolution of diabetic retinopathy in its initial stages, mainly a lower degree of microaneurysms. However, a new approach to controlling endothelial dysfunction shows promise, mainly through the vascular endothelial growth factor (VEGF) inhibitors. These agents may prove to be especially useful in the treatment of proliferative diabetic retinopathy. Other encouraging results have been obtained in studies of antioxidant drugs and inhibitors of the formation of advanced glycation end products. Once retinal lesions appear, preventive measures need to be redoubled, with special attention to controlling glycemia; however, it is also necessary to resort to laser photocoagulation. This intervention aims to eliminate areas of ischemia and to diminish the formation of retinal exudates. If this measure fails or if vitreous hemorrhage appears, the only remaining therapeutic measure is vitrectomy.

Multicenter hospital study on prescribing patterns for prophylaxis and treatment of complications of cirrhosis.

OBJECTIVE: To describe the prescribing patterns for liver disease management. METHODS: A multicenter cross-sectional prospective observational study was carried out in 25 Spanish hospitals. Inpatients, admitted to gastrointestinal and liver units with a diagnosis of liver cirrhosis, were included in five centrally assigned index days between February and June 1999. Information was collected about demographic variables and pharmacological treatments used on admission and recommended at discharge. RESULTS: Five hundred and sixty-eight patients (70% men, mean age 61 years) were studied. Alcoholic cirrhosis of the liver accounted for 44% of the sample, ascites being the most prevalent complication. The most frequent diuretic schedule on admission was the combination of spironolactone and furosemide at a ratio of 1 (100 mg/40 mg). Hospitalization resulted in an increase in the percentage of patients that received the combination at a ratio higher than 1. Diuretics were a major cause of adverse drug events on admission (7.5%). Ulcer-healing drugs showed a notable increase at discharge (35%; range 10-59%) compared with 24% (6-37%) on admission. Utilization rates at discharge were 65% (59-74%) for diuretics, 51% (38-76%) for laxatives, 31% (0-75%) for vitamin K, 24% (4-53%) for beta-adrenergic blocking agents, and 13% (0-47%) for nitrates, which were significantly higher than on admission. CONCLUSION: These results provide the first quantitative data of drug utilization in liver disease and highlight the wide variability in prescribing practices across centers and the higher than expected use of non-evidence-based treatments, especially vitamin K and antiulcer drugs.