Population pharmacokinetics and probability of target attainment of meropenem in critically ill patients

Purpose: Patients admitted to intensive care unit (ICU) with Klebsiella pneumoniae infections are characterized by high mortality. The aims of the present study were to investigate the population pharmacokinetics parameters and to assess the probability of target attainment of meropenem in critically ill patients to provide information for more effective regimens. Methods: Twenty-seven consecutive patients were included in the study. Meropenem was administered as 3-h intravenous (i.v.) infusions at doses of 1\u20132 g every 8 or 12 h. Meropenem plasma concentrations were measured by a high-performance liquid chromatography (HPLC) method, and a population pharmacokinetics analysis was performed using NONMEM software. Meropenem plasma disposition was simulated for extended (3 h; 5 h) or continuous i.v. infusions, and the following parameters were calculated: time during which free drug concentrations were above minimum inhibitory concentration (MIC) (fT > MIC), free minimum plasma concentrations above 4 7 MIC (fCmin > 4 7 MIC), probability of target attainment (PTA), and cumulative fraction of response (CFR). Results: Gender and severity of sepsis affected meropenem clearance, whose typical population values ranged from 6.22 up to 12.04 L/h (mean \ub1 standard deviation (SD) value, 9.38 \ub1 4.47 L/h). Mean Cmin value was 7.90 \ub1 7.91 mg/L, suggesting a high interindividual variability. The simulation confirmed that 88 and 97.5 % of patients achieved effective Cmin > 4 7 MIC values after 3- and 5-h i.v. infusions of meropenem 2 g  7 3/day, respectively. On the contrary, the same total daily doses reached the target Cmin > 4 7 MIC values in 100 % of patients when administered as continuous i.v. infusions. Conclusions: Several factors may influence meropenem pharmacokinetics in ICU patients. Continuous i.v. infusions of meropenem seem to be more effective than standard regimens to achieve optimal therapeutic targets

An Artificial aqueous humor as a standard matrix to assess drug concentration in the anterior chamber by High Performance Liquid Chromatography methods

The aim of the study was to recreate in-vitro artificial aqueous humor with the same physico-chemical properties of human aqueous humor to be used as a standard matrix in chromatography to assess drug concentration in the anterior and posterior chamber of the human eye. Methods: The artificial aqueous humor was prepared according to the human aqueous humor chemical compositions reported in the literature. The artificial matrix was then analysed via the HPLC-UV method and compared with aqueous humor from 15 patients who underwent cataract surgery. Known concentrations of widely-used ophthalmological drugs were added to the artificial aqueous humor in order to assess whether it can be used to explore ocular disposition towards topically or systemically administered drugs. Results: No significant differences were found between the two examined aqueous humor types. There were no significant qualitative differences between examined fluids in terms of presence of ophthalmological drugs. Conclusions: The composition of artificial, in-vitro recreated aqueous humor was similar to that of the human kind. The absence of significant differences in the analysis of tested drugs both in the artificial and in human aqueous humor indicates that artificial aqueous humor may be used to generate a matrix-based standard curve for analytical method validation

Evaluation of Pharmacokinetics and Pharmacodynamics of Deferasirox in Pediatric Patients

Background: Deferasirox (DFX) is commonly used to reduce the chronic iron overload (IO) in pediatric patients. However, the drug is characterized by a large pharmacokinetic variability and approximately 10% of patients may discontinue the treatment due to toxicities. Therefore, the present retrospective study investigated possible correlations between DFX pharmacokinetics and drug-associated toxicities in 39 children (26 males), aged 2–17 years, who underwent an allogeneic hematopoietic stem cell transplantation. Methods: IO was diagnosed by an abdominal magnetic resonance imaging and DFX was started at a median dose of 500 mg/day. DFX plasma concentrations were measured by a high performance liquid chromatographic method with UV detection and they were analysed by nonlinear mixed-effects modeling. Results: The pharmacometric analysis demonstrated that DFX pharmacokinetics were significantly influenced by lean body mass (bioavailability and absorption constant), body weight (volume of distribution), alanine and aspartate transaminases, direct bilirubin, and serum creatinine (clearance). Predicted DFX minimum plasma concentrations (Ctrough) accounted for 32.4 ± 23.2 mg/L (mean ± SD), and they were significantly correlated with hepatic/renal and hematological toxicities (p-value trough threshold values of 7.0 and 11.5 mg/L were chosen, respectively. Conclusions: The population pharmacokinetic model described the interindividual variability and identified Ctrough threshold values that were predictive of hepatic/renal and hematological toxicities associated with DFX

Uncommon Serum Creatine Phosphokinase and Lactic Dehydrogenase Increase during Diosmin Therapy

INTRODUCTION: Short-term administration of diosmin is usually considered safe, with only minor side effects (stomach and abdominal pain, diarrhea, dermatological disorders, and headache) occasionally observed. Within a 4-year period, a general practitioner noticed 17 cases of mild, diosmin-induced side effects, two of which showed particular interest. CASES PRESENTATION: Case 1: A 55-year-old Caucasian woman presented with chronic leg venous insufficiency. She was prescribed diosmin 450mg twice a day. After 5 days of therapy, she developed pain in the legs (myalgia), and diosmin therapy was suspended. She made a spontaneous attempt of drug rechallenge and her leg pain reappeared. Thus, she underwent blood analysis, which showed elevation of creatine phosphokinase levels. Creatine phosphokinase values normalized only after prolonged discontinuation of the therapy. Case 2: A 79-year-old Caucasian man, who was diagnosed with acute hemorrhoidal syndrome. After 21 days of continuous diosmin treatment, increased levels of serum lactic dehydrogenase were detected. In both cases a comprehensive analysis of all possible causes for enzyme elevation was made. CONCLUSIONS: A feasible hypothesis to explain these rare effects could be that exaggerated adrenergic activity occurred on microcirculation, leading to an excessive peripheral vasoconstriction and subsequent ischemic damage. An individual predisposition is strongly suggested. A concurrence of events was probably responsible for the elevation of nonspecific tissue necrosis markers. Physicians and patients must be aware of these rare, but possible, adverse drug reactions

Paliperidone for the treatment of ketamine-induced psychosis: a case report.

Ketamine is an anaesthetic and analgesic drug synthesized in the 1960s from phencyclidine. The recreational use of ketamine increased among the dance culture of techno and house music, in particular in clubs, discotheques, and rave parties. The psychotropic effects of ketamine are now well known and they range from dissociation to positive, negative, and cognitive schizophrenia-like symptoms. We report a case of a chronic oral consumption of ketamine which induced agitation, behavioral abnormalities, and loss of contact with reality in a poly-drug abuser; these symptoms persisted more than two weeks after the drug consumption had stopped. Antipsychotic treatment with paliperidone led to a successful management of the psychosis, getting a complete resolution of the clinical picture. Paliperidone has proven to be very effective in the treatment of ketamine-induced disorders. Moreover, the pharmacological action and metabolism of paliperidone are poorly dependent from the activity of liver enzymes, so that it seems to be one of the best second generation antipsychotics for the treatment of smokers and alcohol abusers. </jats:p

A case report on escitalopram-induced hyperglycaemia in a diabetic patient.

The incidence of depression in diabetic patients is quite high; moreover, it has been suggested that the presence of depression itself may increase the risk of diabetes mellitus. Hence, it follows that the simultaneous use of antidiabetic and antidepressant drugs is common. Some clinical evidence indicates that selective serotonin re-uptake inhibitors (SSRIs) could be very useful in treating overweight patients, both with and without diabetes. However, recent deregulation of glucidic metabolism was tested in diabetic subjects treated with antidepressants. Several cases of hyperglycaemia and hypoglycaemia associated with other SSRIs have been published, whereas only one case of escitalopram inducing hyperglycaemia has been noted. The exact mechanism of glucose control impairment in patients taking SSRIs—escitalopram in particular—still remains unclear. We describe a diabetic 83-year-old woman with good glycaemic control (as evinced by glycaemic and glycosylated haemoglobin assay—HbA1c—values) before escitalopram initiation in response to therapy with glibenclamide. Escitalopram resulted in a significantly increased glycaemia values 5 days following administration. Glycaemia values returned to normality only after suspension of escitalopram, despite antidiabetic dosage increase. We report this case to draw attention to escitalopram as a possible cause of glycaemic control loss. </jats:p