Population Pharmacokinetics of Dasatinib in Healthy Subjects.

BACKGROUND AND OBJECTIVES: Dasatinib is one of the tyrosine kinase inhibitors. The main use of these agents is inhibition of cancerous cell proliferation. The therapeutic importance of tyrosine kinase inhibitors raises the necessity of many types of investigations, especially the pharmacokinetic analysis of these drugs in humans. This analysis, along with other investigations and clinical research, will contribute to the overall knowledge of the drug. This study focused on the population pharmacokinetics of dasatinib. The objective of the study was to investigate the sources of the variability of dasatinib in a population pharmacokinetics study in healthy participants. METHODS: We utilized 4180 plasma observations from 110 subjects who were administered SPRYCEL® on two separate occasions under fasting conditions; data from 20% of the subjects (22 subjects) were extracted for the purpose of internal model evaluation and data from 88 subjects were used in modeling. The model was evaluated by visual predictive check of three different datasets. A two-compartmental model with first order absorption and transit compartment was considered the simplest base model to describe the data based on the corrected Bayesian information criterion evaluation. Covariates were tested through conditional sampling for the stepwise approach-screening procedure in Monolix 2020R1 version. Conditional sampling for the stepwise approach was used to include the correlated covariates within the base model in the forward inclusion step and then to eliminate them backwardly to ensure that the key covariates were kept in the model at the final stage. RESULTS: The effect of body mass index on the absorption rate constant was considered as significant covariate in the final established model. Visual predictive check for simulations, 20% of the original dataset (internal dataset) and an external dataset demonstrated the appropriateness of the final model. CONCLUSIONS: Population pharmacokinetic modeling was performed to describe dasatinib pharmacokinetics in healthy subjects. Body mass index was considered as a factor that might be used in the future along with studies on patients to adjust the dosing regimens. KEY POINTS: Dasatinib is classified as a highly variable drug; this variability was demonstrated in the study by the effect of body mass index on the absorption rate constant.

Population Pharmacokinetics Modeling of Lamotrigine in Jordanian Epileptic Patients Using Dried Blood Spot Sampling.

AIMS: To characterize the population pharmacokinetics of lamotrigine in Jordanian epileptic patients and to identify factors affecting therapeutic parameters. PATIENTS AND METHODS: A population pharmacokinetics model for lamotrigine was established based on a prospectively collected data of 52 steady-state concentrations from 38 adult and pediatric patients with epilepsy. Lamotrigine concentrations were determined by a dried blood spot liquid chromatography method. Data were analyzed according to a one-compartment model with first-order absorption and elimination using the nonlinear mixed effect modeling program. The covariates effect of total body weight, gender, age, and co-medication with topiramate, carbamazepine, phenytoin, phenobarbital, and valproic acid on lamotrigine clearance were investigated using a stepwise forward addition followed by a stepwise backward elimination. RESULTS: The final population pharmacokinetics model for lamotrigine clearance was as follows: CL/Fpop=θ1*exp (θ3*age)*exp (θ5*carbamazepine)*exp (θ6*valproic acid) , where θ1 is the relative clearance (L/hr) estimated, and θ3, θ5, and θ6 are the fixed parameters relating to age and co-medication with carbamazepine and valproic acid, respectively.The population mean value of lamotrigine total clearance generated in the final model (with covariates) was 2.12 L/hr. Inter-individual variability and residual unexplained variability expressed as the coefficient of variation was 37.1 and 26.1%, respectively. CONCLUSION: Lamotrigine total clearance in the Jordanian patients is comparable to that reported by others for Caucasian patients. Age and concomitant therapy with carbamazepine and valproic acid significantly affected lamotrigine clearance, and accounted for 48% of its inter-individual variability.

Wound infiltration with bupivacaine 0.5% with or without adrenaline does not decrease pain after thyroidectomy. A randomized controlled study.

OBJECTIVES: To study the effect of local wound infiltration with and without adrenaline on pain perception after thyroidectomy using the visual analog score (VAS).  Methods: A prospective randomized controlled double-blinded study was conducted between May 2015 and June 2016 at The University of Jordan Hospital, Amman, Jordan. Eighty-nine patients undergoing planned thyroidectomy were included in the study. Patients were divided randomly into 3 groups: Group A, local wound infiltration with bupivacaine 0.5% was administered; Group B, bupivacaine 0.5% with adrenaline was administered; Group C (control), no infiltration was performed. Standardized thyroidectomies were performed in the 3 groups. Pain perception was measured using VAS at 2, 4, 6, 12, and 24 hours after surgery. A comparison between the 3 groups was carried out. Results: No significant differences among the 3 groups were observed at all time points (p=0.246). Visual analog scores were significantly lower at 12 and 24 hours after operations.  Conclusion: Local wound infiltration with bupivacaine 0.5% does not decrease pain perception after thyroidectomy performed under general anesthesia, and adding adrenaline does not enhance its effect.

Comprehensive assessment of treatment related problems in hospitalized medicine patients in Jordan.

OBJECTIVES: The aim of this study was to identify the prevalence and characteristics of treatment related problems (TRPs) in hospitalized internal medicine patients in Jordan as well as to identify diseases and drugs associated with each specific TRP. We have also aimed at investigating physicians' acceptance of recommendations made by clinical pharmacist and to identify the outcomes of pharmacist interventions. SETTING: Internal medicine department of a general hospital in Jordan. METHODS: We have utilized a systematic, prospective, bedside, comprehensive clinical assessment approach that allowed us to effectively identify, communicate and follow up TRPs. MAIN OUTCOME MEASURES: prevalence and nature of identified TRPs, clinical significance of TRPs, associated diseases and drugs and clinical outcomes of clinical pharmacist interventions. RESULTS: 402 patients were included in the study. The average number of the identified TRPs was 9.35. Fifty-three percent of identified TRPs were classified as major and 28% were classified as moderate. Ninety-one percent of the recommendations were accepted by physicians. Efficacy related problems were the most common TRP category followed by safety related problems and indication related problems. Sixty-four percent of the TRPs were resolved or prevented through the clinical pharmacist intervention. CONCLUSIONS: We have found that prevalence of TRPs is substantially high among patients hospitalized at the internal medicine department. TRPs related to Dosage regimens, untreated conditions, patient monitoring, drug interactions, and drug choices were the most common. Most of TRPs identified by pharmacists were clinically significant. Pharmacists' interventions contributed substantially to the resolving of many of the identified TRPs. Patients suffering from higher number of medical conditions and receiving higher number of medications should be given the priority for clinical pharmacy service in hospitalized internal medicine patients.

The effects of pummelo juice on pharmacokinetics of sildenafil in healthy adult male Jordanian volunteers.

PURPOSE: The main purpose of this work was to investigate the effect of pummelo juice on the pharmacokinetics of sildenafil after oral administration. METHODS: This was a comparative, randomized, two-period, two-treatment, two-sequence, single dose, crossover study investigating the effect of pummelo juice on the pharmacokinetics of sildenafil citrate tablets (equivalent to 50 mg sildenafil) in healthy male participants under fasting conditions compared with water as a control. Six healthy normal adult males were administered 50 mg sildenafil with pummelo juice or water at two different periods in a crossover study. RESULTS: Study results showed that pummelo juice reduced the rate and extent of sildenafil bioavailability to around 60% [maximum plasma concentration (C(max)); from 212.44 ng/ml to 134.07 ng/ml, 90% confidence interval (90% CI) 44.70-89.11, and area under the plasma concentration time curve from zero to infinity (AUC(infinity)); from 564.51 ng.hr/ml to 336.87 ng.hr/ml, 90% CI 39.17-90.92]. This interaction was opposite to that expected and is speculated to be due to either an effect on transporters or a physicochemical interaction between sildenafil and some components of the juice. CONCLUSION: Patients should be advised not to drink pummelo juice before or immediately after taking sildenafil.