Pharmazie
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Grapefruit juice (GFJ) is known to affect the pharmacokinetics of a variety of drugs administered concomitantly and this is due to inhibition of intestinal CYP3A, a barrier protein for drug absorption. Some compounds such as furanocoumarin derivatives have been reported as inhibitors of the enzyme. On the other hand, inhibitory potentials of GFJ on CYP3A-oxidation activities differ widely between brands of juices. ⋯ The multiple correlation coefficient (R) and the multiple correlation coefficient with leave-one-out cross validation (Q) of the model equation were 0.94 and 0.91, respectively. These results suggest that the concentrations of ingredients can explain most variances of inhibitory effects among brands. This model may be a useful method for the prediction of the GFJ interaction potential.
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Substituting generic formulations of the same chemical agent is a common practice in German health care on the basis of so called rebate contracts. The substitution of a medication may affect the patients' adherence or result in adverse events. While adverse events which may be caused by the pharmacological activity of the agent itself can be explained, some non-specific side effects cannot be substantiated referring to pharmacological factors. ⋯ But up to 34% of patients being treated for psychological diseases confronted with a change of their medication had additional adverse events. On the basis of the studies analysed, the conclusion can be drawn that the nocebo effect can play a crucial role in the treatment of psychological diseases. Therefore, physicians and pharmacists should be responsible to prevent the nocebo effect through adequately educating the patients.
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The pharmacokinetics of a novel sustained-release oral formulation of morphine have been evaluated. The formulation consisted of tablets containing a morphine-EudragitL complex (MEC) which had shown good sustained-release properties in previous in vitro dissolution studies. MEC tablets were administered orally to beagle dogs and the morphine plasma levels and pharmacokinetic parameters obtained were compared with those obtained with MST Continus, a commercially available sustained release form of morphine. ⋯ Both formulations presented a relatively rapid absorption of morphine with similar values of Cmax (MST: 53 ng/ml; MEC: 50 ng/ml) and Tmax (MST: 86 min; MEC: 88 min), and prolonged morphine plasma levels. Mean plasma morphine concentrations were higher for the MEC tablets than for MST tablets during the terminal phase of the corresponding curves and the mean AUC(0-12h) for MEC tablets was 138% of that obtained with MST tablets. Our findings indicate that MEC tablets can produce prolonged plasma levels of morphine and could be an alternative to commercially available morphine sustained-release forms.
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For patient controlled analgesia, syringes with solutions of 1.5 mg/ml piritramide in 0.9% aqueous sodium chloride are used. The physical and chemical stability for dilutions of the commercially available preparation of piritramide is limited up to 72 hours by the manufacturer. Since application duration for patient-controlled analgesia can exceed that limited time, stability was investigated by HPLC. Our results show that these solutions are chemically stable over a time period of 60 days.
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Nimodipine is used parenterally to treat ischemic neurological deficits caused by subarachnoid haemorraghe. Infusion of nimodipine should be continued during anaesthesia, surgery or angiography. In this context a simultaneous administration of nimodipine, propofol and fentanyl or remifentanil could be of great advantage. ⋯ So the number of oil droplets > 10 microm was determined in combinations of propofol emulsion with nimodipine and fentanyl/remifentanil immediately after mixing and after 20 hours by using microscopy. The experiments showed that all combinations of propofol (1 and 2%) with nimodipine infusion solution resulted in coalescence of oil droplets, which finally caused a visible phase separation. Macrogol (polyethylene glycol 400) was identified as the component in nimodipine infusion solution which induced the physicochemical incompatibility with propofol lipid emulsions.