Pharmacokinetics of orally administered phenobarbital in African grey parrots (Psittacus erithacus erithacus)

Powers, Lauren V.; Papich, Mark G.

doi:10.1111/j.1365-2885.2011.01279.x

Cited by 13 publications

(3 citation statements)

References 8 publications

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“…120 A study in gray parrots has shown that much higher and frequent dosages are needed to achieve similar plasma concentrations as those found effective in humans. 121 It is, therefore, important to measure plasma concentrations of phenobarbital to evaluate the treatment of any bird with epilepsy.…”

Section: Therapeutic Options In Cases Of Convulsive Behaviorsmentioning

confidence: 99%

Medication for Behavior Modification in Birds

Zeeland

2018

Veterinary Clinics of North America: Exotic Animal Practice

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Section: Therapeutic Options In Cases Of Convulsive Behaviorsmentioning

confidence: 99%

Medication for Behavior Modification in Birds

Zeeland

2018

Veterinary Clinics of North America: Exotic Animal Practice

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“…Traditional AED, including phenobarbital and potassium bromide, appear to be safe to use in birds but are considered ineffective, in part because of inadequate blood concentrations due to rapid drug elimination (Beaufrère et al., 2011; Delk, 2012; Powers & Papich, 2011). Furthermore, phenobarbital causes sedation (Thomas, 2010), which is more likely to occur in birds when increasing the dose while seeking clinical response.…”

Section: Introductionmentioning

confidence: 99%

Pharmacokinetics of zonisamide after oral single dosing and multiple‐dose escalation administration in domestic chickens (Gallus gallus)

Matos

Noonan

Schaefer

et al. 2021

Veterinary Medicine & Sci

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Background There are few effective drugs for treatment of seizures in avian species. Objectives To investigate the pharmacokinetics and safety of zonisamide in chickens. Methods Phase 1: chickens (n = 4) received a single oral dose of zonisamide at 20 mg/kg. Blood samples were collected intermittently for 36 hr after dosing. Phase 2: chickens (n = 8) received zonisamide in a dose escalation protocol (20, 30, 60 and 80 mg/kg orally every 12 hr). The dose was increased weekly, and peak and trough blood samples were collected on Days 1, 3, and 7 each week. Two birds were randomly euthanized at the end of each week. Plasma zonisamide concentrations were analysed using a commercial immunoassay. Drug concentration vs. time data were subjected to non‐compartmental pharmacokinetic analysis. Results For Phase 1, peak plasma zonisamide (Cmax) was 15 ± 3 µg/ml at 2 ± 1 hr (Tmax). The disappearance half‐life was 6.5 ± 1 hr. Mean plasma concentrations remained within the (human) therapeutic range (10–40 µg/ml) for 6 hr. For Phase 2 of the study, plasma concentrations of zonisamide remained within or close to the recommended mammalian therapeutic range for birds in the 20 and 30 mg/kg dose. Area under the curve (AUC) and Cmax were dose dependent. Two birds developed immune‐mediated haemolytic anaemia. Conclusions Zonisamide appears to be a viable drug for use in chickens at a dose of 20 mg/kg orally every 12 hr.

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“…Phenobarbital is a common anti-epileptic drug administered in veterinary species for its primary potentiation of the action of GABA on the GABA A receptor resulting in neuronal hyperpolarization (1). Although the pharmacokinetics of phenobarbital administered orally have been investigated in dogs (2), horses (3), and some species of birds (4), no peer reviewed studies are available in ruminants. In clinical practice, phenobarbital is administered orally to manage epilepsy in goats (5).…”

Section: Introductionmentioning

confidence: 99%

Pharmacokinetics of Intravenous and Oral Phenobarbital Sodium in Healthy Goats

et al. 2020

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Phenobarbital is a common drug used to manage epilepsy in goats. However, the recommended dose and dosing frequency are based on studies in dogs and horses. Studies describing the pharmacokinetics of phenobarbital when administered orally and assessing changes in behavior with concurrent electroencephalogram (EEG) readings are warranted in goats. The objectives of this study were to determine the bioavailability of orally administered phenobarbital and determine the effect of phenobarbital on brain activity using EEG in healthy goats. A cross-over design with 8 non-pregnant goats was performed. The goats were administered phenobarbital intravenously at 10 mg/kg, followed by a 2 week wash out period, and then administered phenobarbital, orally, at 10 mg/kg. Plasma sample determination of phenobarbital concentrations were collected at 13 time points. Continuous EEG readings with simultaneous video recording for 12 h was performed to determine the state of vigilance using a behavior scoring system prior to and after phenobarbital administration. Bioavailability of phenobarbital was 24.9%. Mean ± SD for half-life was similar between the oral (3.80 ± 0.826 h) and intravenous (4.0 ± 0.619 h) routes. Time to observed maximum concentration (T max), and maximum plasma concentration (C max) for the oral administration were 1.75 ± 0.46 h and 4,478.7 ± 962.4 ng/mL, respectively. Clearance was 152.5 ± 102.7 ml/h/kg. Area under the curve from zero to infinity (AUC 0→∞) was 155,813 ± 218,448 and 38,763 ± 9,832 h * ng/mL for the intravenous and oral administration routes, respectively. Behavior score at 3 h after phenobarbital administration was different (P = 0.0002) from the score prior to administration for the oral administration route. In contrast, behavior scores before administration of phenobarbital and each time point after administration were not different (P >0.05) for the intravenous administration route or other oral administration route time points. Bioavailability of phenobarbital was poor, and the half-life was very short due to a high clearance. Doses >10 mg/kg should be considered when phenobarbital is administered orally in goats.

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Pharmacokinetics of orally administered phenobarbital in African grey parrots (Psittacus erithacus erithacus)

Cited by 13 publications

References 8 publications

Medication for Behavior Modification in Birds

Medication for Behavior Modification in Birds

Pharmacokinetics of zonisamide after oral single dosing and multiple‐dose escalation administration in domestic chickens (Gallus gallus)

Pharmacokinetics of Intravenous and Oral Phenobarbital Sodium in Healthy Goats

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