Dataset Information

Population pharmacokinetics of extended-release levetiracetam in epileptic dogs when administered alone, with phenobarbital or zonisamide.

ABSTRACT:

Background

Extended-release levetiracetam (LEV-XR) has gained acceptance as an antiepileptic drug in dogs. No studies have evaluated its disposition in dogs with epilepsy.

Hypothesis/objectives

To evaluate the pharmacokinetics of LEV-XR in epileptic dogs when administered alone or with phenobarbital or zonisamide.

Animals

Eighteen client-owned dogs on steady-state maintenance treatment with LEV-XR (Group L, n?=?6), LEV-XR and phenobarbital (Group LP, n?=?6), or LEV-XR and zonisamide (Group LZ, n?=?6).

Methods

Pharmacokinetic study. Blood samples were collected at 0, 2, 4, 8, and 12?hours after LEV-XR was administered with food. Plasma LEV concentrations were determined by high-pressure liquid chromatography. A population pharmacokinetic approach and nonlinear mixed effects modeling were used to analyze the data.

Results

Treatment group accounted for most of the interindividual variation. The LP group had lower C_MAX (13.38??g/mL) compared to the L group (33.01??g/mL) and LZ group (34.13??g/mL), lower AUC (134.86 versus 352.95 and 452.76?hours·?g/mL, respectively), and higher CL/F (0.17 versus 0.08 and 0.07?L/kg/hr, respectively). The half-life that defined the terminal slope of the plasma concentration versus time curve (~5 hours) was similar to values previously reported for healthy dogs.

Conclusions and clinical importance

Considerable variation exists in the pharmacokinetics of LEV-XR in dogs with epilepsy being treated with a common dose regimen. Concurrent administration of phenobarbital contributed significantly to the variation. Other factors evaluated, including co-administration of zonisamide, were not shown to contribute to the variability. Drug monitoring may be beneficial to determine the most appropriate dose of LEV-XR in individual dogs.

SUBMITTER: Munana KR

PROVIDER: S-EPMC6189379 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature

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Publications

Population pharmacokinetics of extended-release levetiracetam in epileptic dogs when administered alone, with phenobarbital or zonisamide.

Muñana Karen R KR Otamendi Arturo J AJ Nettifee Julie A JA Papich Mark G MG

Journal of veterinary internal medicine 20180920 5

<h4>Background</h4>Extended-release levetiracetam (LEV-XR) has gained acceptance as an antiepileptic drug in dogs. No studies have evaluated its disposition in dogs with epilepsy.<h4>Hypothesis/objectives</h4>To evaluate the pharmacokinetics of LEV-XR in epileptic dogs when administered alone or with phenobarbital or zonisamide.<h4>Animals</h4>Eighteen client-owned dogs on steady-state maintenance treatment with LEV-XR (Group L, n = 6), LEV-XR and phenobarbital (Group LP, n = 6), or LEV-XR and z ...[more]

PMID: 30238679

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Project description:Backgroundα2-Adrenoceptor agonists are used adjunctively to psychostimulants in treating attention-deficit/hyperactivity disorder (ADHD) when psychostimulants alone do not sufficiently reduce symptoms. However, data on the pharmacokinetic profiles and safety of combination treatments in ADHD are needed.ObjectiveThe primary objective of this study was to evaluate the pharmacokinetic profiles of guanfacine extended release (GXR) and methylphenidate hydrochloride (MPH) extended release, alone and in combination.Study designThis was an open-label, randomized, three-period crossover, drug-drug interaction study.SettingThe study was conducted at a single clinical research center.ParticipantsThirty-eight healthy adults were randomized in this study.InterventionsSubjects were administered single oral doses of GXR (Intuniv(®); Shire Development LLC, Wayne, PA, USA) 4 mg, MPH (Concerta(®); McNeil Pediatrics, Titusville, NJ, USA) 36 mg, or GXR and MPH combined.Main outcome measuresGuanfacine, dexmethylphenidate (d-MPH), and l-methylphenidate (l-MPH) levels were measured with blood samples collected predose and up to 72 h postdose. Safety evaluations included treatment-emergent adverse events (TEAEs), vital signs, and electrocardiograms (ECGs).ResultsThirty-five subjects completed the study. Analyses of the 90 % confidence intervals (CIs) for the geometric mean ratios of the maximum plasma concentration (Cmax) and area under the concentration-time curve extrapolated to infinity (AUC∞) values for guanfacine and d-MPH following administration of GXR or MPH alone or combined met strict bioequivalence criteria (90 % CIs within the interval of 0.80-1.25). Overall, combining GXR and MPH did not alter the pharmacokinetic parameters of either medication. Sixteen subjects (42.1 %) had at least one TEAE. The most commonly reported TEAEs included headache and dizziness following GXR, MPH, and GXR and MPH combined. Two subjects had clinically significant abnormalities in ECG results following coadministration: both events were mild and resolved the same day.ConclusionsIn this short-term, open-label study of healthy adults, coadministration of GXR and MPH did not result in significant pharmacokinetic drug-drug interactions. No unique TEAEs were observed with coadministration of GXR and MPH compared with either treatment alone.

Project description:Importance:More than half of infants with new-onset epilepsy have electroencephalographic and clinical features that do not conform to known electroclinical syndromes (ie, nonsyndromic epilepsy). Levetiracetam and phenobarbital are the most commonly prescribed medications for epilepsy in infants, but their comparative effectiveness is unknown. Objective:To compare the effectiveness of levetiracetam vs phenobarbital for nonsyndromic infantile epilepsy. Design, Setting, and Participants:The Early Life Epilepsy Study-a prospective, multicenter, observational cohort study conducted from March 1, 2012, to April 30, 2015, in 17 US medical centers-enrolled infants with nonsyndromic epilepsy and a first afebrile seizure between 1 month and 1 year of age. Exposures:Use of levetiracetam or phenobarbital as initial monotherapy within 1 year of the first seizure. Main Outcomes and Measures:The binary outcome was freedom from monotherapy failure at 6 months, defined as no second prescribed antiepileptic medication and freedom from seizures beginning within 3 months of initiation of treatment. Outcomes were adjusted for demographics, epilepsy characteristics, and neurologic history, as well as for observable selection bias using propensity score weighting and for within-center correlation using generalized estimating equations. Results:Of the 155 infants in the study (81 girls and 74 boys; median age, 4.7 months [interquartile range, 3.0-7.1 months]), those treated with levetiracetam (n?=?117) were older at the time of the first seizure than those treated with phenobarbital (n?=?38) (median age, 5.2 months [interquartile range, 3.5-8.2 months] vs 3.0 months [interquartile range, 2.0-4.4 months]; P?<?.001). There were no other significant bivariate differences. Infants treated with levetiracetam were free from monotherapy failure more often than those treated with phenobarbital (47 [40.2%] vs 6 [15.8%]; P?=?.01). The superiority of levetiracetam over phenobarbital persisted after adjusting for covariates, observable selection bias, and within-center correlation (odds ratio, 4.2; 95% CI, 1.1-16; number needed to treat, 3.5 [95% CI, 1.7-60]). Conclusions and Relevance:Levetiracetam may have superior effectiveness compared with phenobarbital for initial monotherapy of nonsyndromic epilepsy in infants. If 100 infants who received phenobarbital were instead treated with levetiracetam, 44 would be free from monotherapy failure instead of 16 by the estimates in this study. Randomized clinical trials are necessary to confirm these findings.

Project description:BackgroundIn clinical practice, α₂-adrenoceptor agonists have been adjunctively administered with psychostimulants for the treatment of attention-deficit/hyperactivity disorder (ADHD). Two studies have examined the adjunctive use of guanfacine extended release (GXR, Intuniv®; Shire Development LLC, Wayne, PA, USA) with psychostimulants in children and adolescents with a suboptimal response to psychostimulant treatment. However, the potential for pharmacokinetic drug-drug interactions (DDIs) between GXR and lisdexamfetamine dimesylate (LDX, Vyvanse®; Shire US LLC, Wayne, PA, USA) has not been thoroughly evaluated.ObjectiveThe primary objective of this study was to examine the pharmacokinetics of GXR 4 mg and LDX 50 mg given as single doses alone and in combination.Study designThis was an open-label, randomized, three-period crossover, DDI study.SettingThe study was conducted in a single clinical research center.ParticipantsForty-two healthy adults were randomized in this study.InterventionsSubjects were administered single oral doses of GXR 4 mg, LDX 50 mg, or GXR and LDX in combination.Main outcome measuresBlood samples collected predose and up to 72 h postdose assessed guanfacine, LDX, and d-amphetamine levels. Bioequivalence was defined as the 90% confidence intervals (CIs) of the geometric mean ratios of the area under the plasma concentration-time curve extrapolated to infinity (AUC0-∞) and maximum plasma concentration (Cmax) falling within the bioequivalence reference interval (0.80-1.25). Safety measures included adverse events, vital signs, and electrocardiograms (ECGs).ResultsForty subjects completed the study. Following administration of LDX alone or in combination with GXR, the statistical comparisons of the AUC0-∞ and Cmax of d-amphetamine fell entirely within the reference interval. For guanfacine, the 90% CI of the geometric mean ratio of AUC∞ for the two treatments was within the bioequivalence criteria, but for Cmax the upper bound of the 90% CI exceeded the standard range for bioequivalence by 7%. This relatively small change is unlikely to be clinically meaningful. Treatment-emergent adverse events (TEAEs) were reported by 42.9% of subjects; the most commonly reported TEAEs included dizziness (5.0, 7.3, and 7.3%) and headache (7.5, 4.9, and 7.3%) following administration of GXR, LDX, and GXR and LDX in combination, respectively. Clinically significant ECG abnormalities occurred in one subject following administration of LDX and in one subject following coadministration of GXR and LDX.ConclusionsIn healthy adults, coadministration of GXR and LDX did not result in a clinically meaningful pharmacokinetic DDI compared with either treatment alone. No unique TEAEs were observed with coadministration of GXR and LDX compared with either treatment alone.

Project description:BackgroundLisdexamfetamine dimesylate (LDX), a prodrug consisting of d-amphetamine and l-lysine, is being studied in clinical trials of major depressive disorder. Additional drug-drug interaction studies were warranted.ObjectiveThis study aimed to describe the pharmacokinetics and safety of LDX and venlafaxine extended-release (VXR), alone or combined.Study designThe study was an open-label, two-arm, single-sequence crossover investigation with randomization to treatment sequence.Setting and participantsThe study was conducted at two clinical study centres and included healthy adult males and females (18-45 years of age).InterventionThe study included two single-sequence crossover designs: LDX alone followed by LDX + VXR (Treatment Arm A); and VXR alone followed by VXR + LDX (Treatment Arm B). Drug treatment was initiated on day 1 with once-daily LDX or VXR alone with 15 days' titration to final dose (LDX 30, 50 and 70 mg for 5 days each; VXR 75, 150 and 225 mg for 5 days each). On days 16-30, VXR, titrated to a final dose of 225 mg, or LDX, titrated to a final dose of 70 mg, was coadministered for participants in Treatment Arm A or B, respectively. On days 31-38, VXR doses were tapered.Main outcome measuresOn days 1-2, 15-16 and 30-31, safety evaluations and blood samples were obtained pre-dose through 24 h post-dose for analysis of LDX, d-amphetamine, venlafaxine (VEN), and O-desmethylvenlafaxine (ODV). Combination treatment was considered bioequivalent to single treatment if 90 % confidence intervals (CIs) for geometric mean ratios (GMRs) of analytes fell within the interval 0.80-1.25 based on maximum plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC) from time zero to time of last measurable concentration (AUCτ). Safety assessments included treatment-emergent adverse events (TEAEs), pulse rate and blood pressure (BP), clinical laboratory assessments, and 12-lead electrocardiograms (ECG).ResultsAmong 80 enrolled subjects, 77 were included in pharmacokinetic and safety analyses. Combination LDX + VXR was bioequivalent to LDX alone, based on exposure to d-amphetamine (GMR [95 % CI], Cmax (ng/mL): 0.97 [0.82, 1.14], AUCτ: 0.95 [0.81, 1.12]). Exposure to VEN with LDX + VXR (vs. VXR alone) was increased (Cmax: 1.10 [0.88, 1.38], AUCτ: 1.13 [0.88, 1.45]) and ODV decreased (Cmax: 0.91 [0.77, 1.06], AUCτ: 0.83 [0.71, 0.96]), whereas composite VEN + ODV was bioequivalent to VXR alone (Cmax: 0.96 [0.84, 1.09], AUCτ: 0.98 [0.85, 1.13]). TEAEs with LDX or LDX + VXR were similar. Maximum mean increases from baseline were: pulse rate, +8.73 to 12.76 beats/min with either treatment alone and +17.67 to 20.85 beats/min with LDX + VXR; systolic BP, +4.32 to 6.56 mmHg with either treatment alone and +12.96 to 13.78 mmHg with LDX + VXR; diastolic BP, +5.39 to 5.74 mmHg with either treatment alone and +12.09 to 12.46 mmHg with LDX + VXR. One participant was withdrawn due to a serious TEAE (presyncope). No unexpected, clinically meaningful trends or changes from baseline in mean laboratory or ECG parameters were observed during the trial.ConclusionIn healthy adults, combination LDX + VXR (vs. LDX alone) did not alter exposure to d-amphetamine. Although small changes in exposure to VEN (increased) and ODV (decreased) were seen with combination treatment, total VEN + ODV exposure showed no change (vs. VEN alone). LDX + VXR led to increases in BP and pulse rate, supporting existing recommendations for vital sign monitoring when using these medications.

Dataset Information

Population pharmacokinetics of extended-release levetiracetam in epileptic dogs when administered alone, with phenobarbital or zonisamide.

Background

Hypothesis/objectives

Animals

Methods

Results

Conclusions and clinical importance

Publications

Population pharmacokinetics of extended-release levetiracetam in epileptic dogs when administered alone, with phenobarbital or zonisamide.

Similar Datasets

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