Population Pharmacokinetics of Sertraline in Psychiatric and Substance Use Disorders.

This study aimed to characterize the population pharmacokinetics of sertraline in Mexican patients with psychiatric and substance use disorders. Fifty-nine patients (13 to 76 years old) treated with doses of sertraline between 12.5 and 100 mg/day were included. Plasma sertraline concentrations were determined in blood samples and five of the main substances of abuse were determined by rapid tests in urine samples. Demographic, clinical, and pharmacogenetic factors were also evaluated. Population pharmacokinetic analysis was performed using NONMEM software with first-order conditional estimation method. A one-compartment model with proportional residual error adequately described the sertraline concentrations versus time. CYP2D6*2 polymorphism and CYP2C19 phenotypes significantly influenced sertraline clearance, which had a population mean value of 66 L/h in the final model. The absorption constant and volume of distribution were fixed at 0.855 1/h and 20.2 L/kg, respectively. The model explained 11.3% of the interindividual variability in sertraline clearance. The presence of the CYP2D6*2 polymorphism caused a 23.1% decrease in sertraline clearance, whereas patients with intermediate and poor phenotype of CYP2C19 showed 19.06% and 48.26% decreases in sertraline clearance, respectively. The model was internally validated by bootstrap and visual predictive check. Finally, stochastic simulations were performed to propose dosing regimens to achieve therapeutic levels that contribute to improving treatment response.

Pharmacogenetic potential biomarkers for carbamazepine adverse drug reactions and clinical response.

Carbamazepine (CBZ) is a first-line widely used anticonvulsant. It has a narrow therapeutic index and exhibits considerable interindividual and interethnic variability in clinical efficacy and adverse drug reactions including potentially life-threatening hypersensitivity reactions, such as Stevens-Johnson syndrome and toxic epidermal necrolysis. The most important pharmacogenetic finding is related to the association of CBZ-induced hypersensitivity with human leukocyte antigens (HLA class I and II alleles). Moreover, genotyping for HLA-B*15:02 allele is required prior to initiating CBZ in Asians and Asian ancestry patients, demonstrating the usefulness of biomarkers to avoid adverse drug reactions. On the other hand, in order to explain the differences in the clinical response to CBZ, genetic polymorphisms in phase I (CYP3A4, CYP3A5 and EPHX1) and phase II (UGT2B7) metabolising enzymes have been assessed; additionally, the influence of transporters (ABCB1 and ABCC2), receptors (PXR) and other drug targets (voltage- gated Na+ channels) in CBZ clinical response has been evaluated. To date, these studies are controversial and require further investigations to clarify the functional role of these polymorphisms as potential biomarkers in regard to CBZ therapy.

Clinical and electroencephalographic assessment of cefepime during treatment of nosocomial infections in neurological patients.

OBJECTIVE: Cefepime neurotoxicity usually occurs in patients with renal impairment. The aim of this study was to evaluate the neurotoxicity of cefepime administered by continuous intravenous infusion during treatment of nosocomial infections in neurological patients with normal renal function. METHODS: This was an open pilot study of neurological patients with infections caused by cefepime sensitive bacteria. Patients had baseline neurological assessment and electroencephalogram (EEG). Cefepime plasma concentrations were determined 48 hours after infusion was initiated and at end of treatment (EOT). RESULTS: Eleven patients were included. These were diagnosed with a brain tumor (9), cerebrovascular disease (1) and polyneuropathy (1). Infections were surgical site infection in 5, clinically defined nosocomial pneumonia in 4, and bacterial meningitis associated to postoperative CSF fistula in 2. Gram-negative organisms were isolated in 10 patients. Cefepime dose was 2 g/day in 9 patients and 4 g/day in 2. Mean cefepime plasma concentration at 48h was 13.6 ± 2.0 µg/mL (range 4.6 to 24.5 µg/mL), at EOT was 11.9 ± 1.8 µg/mL (range 3.0 to18.9 µg/mL ). EEG interpreted by two experts showed at baseline alpha background rhythm in 5 and theta-alpha rhythm in 6 patients. On EEG at EOT background rhythm was alpha in 4 and theta-alpha in 7, one patient presented isolated sharp and slow wave activity. No mental status changes or seizures occurred and all infections resolved. CONCLUSION: Significant EEG change was observed in 1of 11 patients. A preserved mental status may correlate with cefepime safety in neurological patients with normal renal function during cefepime treatment.

Enhancement of antinociception by co-administration of ibuprofen and caffeine in arthritic rats.

It has been observed that caffeine improves antinociceptive efficacy of some non-steroidal antiinflammatory drugs (NSAIDs) in several experimental models, however, these effects have been questioned in humans. Controversy in clinical studies may be due to the use of different protocols as well as to high interindividual variability in patient response. In addition, the antinociceptive interaction of ibuprofen+caffeine has not been studied. To assess a possible synergistic antinociceptive interaction, the antinociceptive effects of ibuprofen, and caffeine administered either separately or in combinations were determined in a model of arthritic pain: "Pain-induced functional impairment in the rat (PIFIR model). The antinociceptive efficacies were evaluated using several dose-response curves and time courses. The antinociceptive effects from the combination that produced the greater effect were compared with the maximal antinociceptive effect of either morphine or acetylsalicylic acid alone. The animals were administered with 0.05 ml intra-articular (i.a.) of uric acid to induce nociception. Groups of six rats received either acetylsalicylic acid, morphine, ibuprofen or caffeine, or a combination ibuprofen+caffeine (18 combinations). We report here that caffeine (17.8 and 31.6 mg/kg) is able to potentiate the antinociceptive effect of ibuprofen. This investigation showed that six combinations presented effects of potentiation and twelve combinations only showed antinociceptive effects not different from that of ibuprofen alone. The maximum antinociceptive effect was 270.7+/-12.7 area units (au), produced by ibuprofen 100 mg/kg+caffeine 17.8 mg/kg; this effect was greater than the maximum produced by morphine 17.8 mg/kg (244.7+/-22.9 au) in these experimental conditions. The maximum potentiation was 197 % produced with the combination of ibuprofen 17.8 mg/kg+caffeine 17.8 mg/kg. These results suggest that the antinociceptive effect of ibuprofen was significantly potentiated by doses of caffeine that by themselves are ineffective in this model.

In vitro effects of albendazole sulfoxide and praziquantel against Taenia solium and Taenia crassiceps cysts.

We investigated the minimum exposure times of prazicuantel (PZQ) and albendazole sulfoxide (ABZSO) required for their activities against Taenia cysts in vitro as well as the 50 and 99% effective concentrations. The results showed that although the effects of both drugs are time and concentration dependent, ABZSO acts much slower and is less potent than PZQ.

Pharmacokinetics of HEPP, a new anticonvulsant, in healthy subjects and rabbits after multiple doses.

In the present study the pharmacokinetics of D,L-3hydroxy-3-phenylpropionamide (HEPP) a new anticonvulsant compound was studied after multiple dose administration in healthy male volunteers and in rabbits. The study in humans involved the oral administration of 375 mg of HEPP b.i.d. for 7 consecutive days. The study in rabbits explored doses of 30 mg/kg intraperitoneal (i.p.) given once daily for 6 days. In both studies pharmacokinetic (PK) profiles were characterized after the first dose and after the last multiple dose. Plasma HEPP concentrations were measured by HPLC. Pharmacokinetic parameters were calculated by noncompartmental methods. The results in humans as well as in rabbits showed that after multiple doses the AUC values decreased and CL/F values were significantly increased, which could be due to an induction process in the metabolic disposition of the drug.