Selective Induction of Human Hepatic Cytochromes P450 2B6 and 3A4 by Metamizole
ABSTRACT The pyrazolone drug metamizole is a widely used analgesic. Analysis of liver microsomes from patients treated with metamizole revealed selectively higher expression of cytochromes P450, CYP2B6 and CYP3A4 (3.8- and 2.8-fold, respectively), and 2.9-fold higher bupropion hydroxylase activity compared with untreated subjects. Further investigation of metamizole and various derivatives on different potential target genes in human primary hepatocytes demonstrated time- and concentration-dependent induction by metamizole of CYP2B6 (7.8- and 3.1-fold for mRNA and protein, respectively, at 100 muM) and CYP3A4 (2.4- and 2.9-fold, respectively), whereas other genes (CYP2C9, CYP2C19, CYP2D6, NADPH:cytochrome P450 reductase, ABCB1, constitutive androstane receptor (CAR), pregnane X receptor (PXR)) were not substantially altered. Using reporter gene assays, we show that metamizole is not acting as a direct ligand to either PXR or CAR, suggesting a phenobarbital-like mechanism of induction. These data warrant further studies to elucidate the drug-interaction potential of metamizole, especially in patients with long-term treatment.
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ABSTRACT: Pain management in patients with liver cirrhosis is a real challenge and is often inadequate due to a lack of therapeutic efficacy or the high incidence of adverse effects. The focus of treatment differs depending on whether the pain is acute or chronic and involves understanding the causative pathophysiological mechanism. Analgesics should be started with the minimum effective dose and should be titrated slowly with avoidance of polypharmacy. Adverse effects must be monitored, especially sedation and constipation, which predispose the patient to the development of hepatic encephalopathy. The first-line drug is paracetamol, which is safe at doses of 2-3 g/day. Non-steroidal anti-inflammatory agents are contraindicated because they can cause acute renal failure and/or gastrointestinal bleeding. Tramadol is a safe option for moderate-severe pain. The opioids with the best safety profile are fentanyl and hydromorphone, with methadone as an alternative. Topical treatment can reduce oral drug consumption. In neuropathic pain the first-line therapeutic option is gabapentin. The use of antidepressants such as amitriptyline can be considered in some patients. Interventional techniques are a valuable tool in moderate to severe pain, since they allow a reduction in drug therapy and consequently its adverse effects. Psychological treatment, physical therapy and rehabilitation should be considered as part of multimodality therapy in the management of chronic pain.Gastroenterología y Hepatología 01/2013; DOI:10.1016/j.gastrohep.2013.05.007 · 0.83 Impact Factor
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ABSTRACT: Studies on liver regeneration following partial hepatectomy (PH) have identified several microRNAs (miRNAs) that show a regulated expression pattern. These studies involve major surgery to access the liver, which is known to have intrinsic effects on hepatic gene expression and may also affect miRNA screening results. We performed two-third PH or sham laparotomy (SL) in Wistar rats to investigate the effect of both procedures on miRNA expression in liver tissue and corresponding plasma samples by microarray and qRT-PCR analyses. As control groups, non-treated rats and rats undergoing anesthesia only were used.BMC Research Notes 10/2014; 7(1):702. DOI:10.1186/1756-0500-7-702
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ABSTRACT: Pulmonary hypertension is a progressive disease of diverse origin with devastating consequences in adults as well as in children. The phosphodiesterase 5 inhibitor sildenafil successfully lowers pulmonary vascular resistance. However, because of its poor enteral absorption, resulting in ineffective plasma concentrations, responses in infants and children are often erratic.Case presentations: We report the cases of two Caucasian boys, one born at term (case 1) and one aged 2.5 years (case 2), who had structural cardiac and pulmonary defects accompanied by symptomatic pulmonary hypertension. They received sildenafil enterally and sublingually and also intravenously in one of them. Plasma samples were taken at various time points to determine the plasma concentrations of sildenafil and its partially active metabolite. Sildenafil and N-desmethyl sildenafil were quantified using a validated liquid chromatography/mass spectrometry method. Oxygen partial pressure was determined from routine arterial blood gas samples.Journal of Medical Case Reports 05/2014; 8(1):171. DOI:10.1186/1752-1947-8-171