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  • Author or Editor: Keven Flammer x
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Abstract

Objective—To determine the pharmacokinetics and effects of orally administered fluconazole in African grey parrots.

Animals—40 clinically normal Timneh African grey parrots (Psittacus erithacus timneh).

Procedure—In single-dose trials, parrots were placed into groups of 4 to 5 birds each and fluconazole was administered orally at 10 and 20 mg/kg. Blood samples for determination of plasma fluconazole concentrations were collected from each group at 2 or 3 of the following time points: 1, 3, 6, 9, 12, 24, 31, 48, and 72 hours. In multiple-dose trials, fluconazole was administered orally to groups of 5 birds each at doses of 10 and 20 mg/kg every 48 hours for 12 days. Trough plasma concentrations were measured 3 times during treatment. Groups receiving 20 mg/kg were monitored for changes in plasma biochemical analytes, and blood samples were collected on days 1 and 13 of treatment to allow comparison of terminal half-life.

Results—Peak plasma concentrations of fluconazole were 7.45 and 18.59 μg/mL, and elimination half-lives were 9.22 and 10.19 hours for oral administration of 10 and 20 mg/kg, respectively. Oral administration of fluconazole for 12 days at 10 or 20 mg/kg every 48 hours did not cause identifiable adverse effects or change the disposition of fluconazole.

Conclusions and Clinical Relevance—Oral administration of fluconazole to parrots at 10 to 20 mg/kg every 24 to 48 hours maintains plasma concentrations above the minimum inhibitory concentration for several common yeast species. The prolonged dosing interval is an advantage of this treatment regimen.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine efficacy of providing drinking water medicated with doxycycline for treatment of spiral bacterial infection in cockatiels.

Design—Randomized controlled clinical trial.

Animals—18 cockatiels (Nymphicus hollandicus) naturally infected with spiral bacteria.

Procedures—Spiral bacterial infection was diagnosed by means of cytologic examination of swab specimens from the choana and oropharynx. Eleven birds (treatment group) were given drinking water to which doxycycline hyclate had been added at a concentration of 400 mg/L for 30 days; the remaining 7 birds (control group) were given unmedicated water. After completion of the study, 6 control birds were treated with drinking water medicated with doxycycline for 21 days.

Results—Daily mean plasma doxycycline concentration for birds in the treatment group ranged from 2.26 to 2.86 Mg/mL (overall range, 0.83 to 4.34 Mg/mL). All treated birds were negative for spiral bacteria after treatment for 21 days and remained negative when examined 160 days after treatment ended. Control birds remained positive for spiral bacteria. Control birds treated with doxycycline after completion of the study were negative for spiral bacteria after treatment for 21 days and 30 days after treatment ended. No clinically important adverse effects were associated with treatment.

Conclusions and Clinical Relevance—Results suggested that providing drinking water to which doxycycline had been added at a concentration of 400 mg/L was effective in eliminating spiral bacterial infections in cockatiels.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether plasma doxycycline concentrations considered effective for treatment of avian chlamydiosis could be safely established and maintained in budgerigars via administration of doxycycline in water or seed.

Design—Prospective study.

Animals—68 healthy mature budgerigars.

Procedure—In 14-day trials, plasma doxycycline concentrations were measured in budgerigars provided with water containing 0, 50, 100, 200, or 400 mg of doxycycline hyclate/L or a hulled seed diet containing 0, 100, 200, or 400 mg of doxycycline hyclate/kg. On the basis of these results, birds were fed seed containing 300 mg of doxycycline/kg for 42 days, and a control group received unmedicated seed. Blood samples for plasma doxycycline analysis were collected either in the morning on treatment days 4, 7, 14, 21, 28, 35, and 42 or in the afternoon on days 12, 26, and 40. Birds were observed daily. On days 14, 28, and 42, physical and plasma biochemical variables, PCV, and total solids concentration were measured; cloacal specimens were obtained for bacteriologic and fungal culture.

Results—During a 14-day period, treatment with water containing ≤ 400 mg of doxycycline/L did not maintain plasma doxycycline concentrations of ≥ 1 μg/mL, but seed containing 300 mg of doxycycline hyclate/kg maintained mean plasma doxycycline concentrations > 0.98 μg/mL for 42 days without notable adverse effects.

Conclusions and Clinical Relevance—Results suggest that hulled seed containing 300 mg of doxycycline hyclate/kg can safely establish and maintain plasma doxycycline concentrations that are considered adequate for treatment of chlamydiosis in adult nonbreeding budgerigars. (J Am Vet Med Assoc 2003; 223:993–998)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether end-tidal partial pressure of carbon dioxide (PETCO2) correlated with PaCO2 in isoflurane-anesthetized African grey parrots receiving intermittent positive pressure ventilation (IPPV).

Design—Prospective study.

Animals—14 healthy mature African grey parrots (Psittacus erithacus timnus).

Procedure—Each bird was anesthetized via mask with isoflurane, intubated, and connected to a pressure-limited intermittent-flow ventilator. Respiratory rate was altered while holding peak inspiratory pressure constant (5 cm H2O) to achieve a PETCO2 in 1 of 3 ranges: < 30 mm Hg, 30 to 40 mm Hg, and > 40 mm Hg. Blood was collected from the superficial ulnar artery of each bird at least once during each of the 3 ranges. Arterial blood samples were collected for blood gas analysis while PETCO2 was recorded simultaneously.

Results—A strong correlation between PETCO2 and PaCO2 was detected over a wide range of partial pressures, although PETCO2 consistently overestimated PaCO2 by approximately 5 mm Hg. End-tidal partial pressure of CO2 and PaCO2 also correlated well with arterial blood pH, and the acute response of the bicarbonate buffer system to changes in ventilation was similar to that of mammals.

Conclusions and Clinical Relevance—Results indicated that PETCO2 reliably estimates PaCO2 in isofluraneanesthetized African grey parrots receiving IPPV and suggest that IPPV combined with capnography is a viable option for anesthetic maintenance in avian anesthesia. (J Am Vet Med Assoc 2001;219:1714–1718)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the pharmacokinetics and safety of orally administered voriconazole in African grey parrots.

Animals—20 clinically normal Timneh African grey parrots (Psittacus erithacus timneh).

Procedures—In single-dose trials, 12 parrots were each administered 6, 12, and 18 mg of voriconazole/kg orally and plasma concentrations of voriconazole were determined via high-pressure liquid chromatography. In a multiple-dose trial, voriconazole (18 mg/kg) was administered orally to 6 birds every 12 hours for 9 days; a control group (2 birds) received tap water. Treatment effects were assessed via observation, clinicopathologic analyses (3 assessments), and measurement of trough plasma voriconazole concentrations (2 assessments).

Results—Voriconazole's elimination half-life was short (1.1 to 1.6 hours). Higher doses resulted in disproportional increases in the maximum plasma voriconazole concentration and area under the curve. Trough plasma voriconazole concentrations achieved in the multiple-dose trial were lower than those achieved after administration of single doses. Polyuria (the only adverse treatment effect) developed in treated and control birds but was more severe in the treatment group.

Conclusions and Clinical Relevance—In African grey parrots, voriconazole has dose-dependent pharmacokinetics and may induce its own metabolism. Oral administration of 12 to 18 mg of voriconazole/kg twice daily is a rational starting dose for treatment of African grey parrots infected with Aspergillus or other fungal organisms that have a minimal inhibitory concentration for voriconazole ≤ 0.4 μg/mL. Higher doses may be needed to maintain plasma voriconazole concentrations during long-term treatment. Safety and efficacy of various voriconazole treatment regimens in this species require investigation.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the pharmacokinetics and safety of voriconazole administered orally in single and multiple doses in Hispaniolan Amazon parrots (Amazona ventralis).

Animals—15 clinically normal adult Hispaniolan Amazon parrots.

Procedures—Single doses of voriconazole (12 or 24 mg/kg) were administered orally to 15 and 12 birds, respectively; plasma voriconazole concentrations were determined at intervals via high-pressure liquid chromatography. In a multiple-dose trial, voriconazole (18 mg/kg) or water was administered orally to 6 and 4 birds, respectively, every 8 hours for 11 days (beginning day 0); trough plasma voriconazole concentrations were evaluated on 3 days. Birds were monitored daily, and clinicopathologic variables were evaluated before and after the trial.

Results—Voriconazole elimination half-life was short (0.70 to 1.25 hours). In the single-dose experiments, higher drug doses yielded proportional increases in the maximum plasma voriconazole concentration (Cmax) and area under the curve (AUC). In the multiple-dose trial, Cmax, AUC, and plasma concentrations at 2 and 4 hours were decreased on day 10, compared with day 0 values; however, there was relatively little change in terminal half-life. With the exception of 1 voriconazole-treated parrot that developed polyuria, adverse effects were not evident.

Conclusions and Clinical Relevance—In Hispaniolan Amazon parrots, oral administration of voriconazole was associated with proportional kinetics following administration of single doses and a decrease in plasma concentration following administration of multiple doses. Oral administration of 18 mg of voriconazole/kg every 8 hours would require adjustment to maintain therapeutic concentrations during long-term treatment. Safety and efficacy of voriconazole treatment in this species require further investigation.

Full access
in American Journal of Veterinary Research
Restricted access
in Journal of the American Veterinary Medical Association