Milbemycin oxime (Interceptor) treatment of amphipod parasites (Hyperiidae) from several host jellyfish species.

Wild-caught crystal jellyfish (Aequorea victoria) arrived at the John G. Shedd Aquarium infested with hyperiid amphipods (Hyperia medusarum), which were inadvertently introduced into a system containing several jellyfish species. Affected systems were treated with milbemycin oxime (Interceptor tablets for dogs 51-100 lbs, Novartis Animal Health US, Inc., Greensboro, North Carolina 27408, USA), a treatment prescribed for red bug (Tegastes acroporanus) infestation in corals. Two treatments using one 25-mg aliquot of Interceptor per 10 gallons of tank water administered 6-7 days apart were completed. Overall, treatment to eradicate the parasite from the affected systems was successful. Further studies evaluating the tolerance of jellyfish to milbemycin oxime, particularly in small juvenile Eutonina indicans and Aurelia aurita, are warranted. Based on clinical observations, there were more negative effects associated with the treatment in the hydrozoans than in the scyphozoans.

PHARMACOKINETICS OF TRAMADOL HYDROCHLORIDE AND ITS METABOLITE O-DESMETHYLTRAMADOL FOLLOWING A SINGLE, ORALLY ADMINISTERED DOSE IN CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS).

Tramadol is a synthetic, centrally acting, opiate-like analgesic that is structurally related to codeine and morphine. The objective of this study was to determine the pharmacokinetics of tramadol hydrochloride and its major active metabolite O-desmethyltramadol (M1) in the California sea lion (Zalophus californianus). A single dose of tramadol was administered orally in fish at 2 mg/kg to a total of 15 wild California sea lions admitted for rehabilitation. Twenty-four total blood samples were collected post drug administration at 10, 20, 30, and 45 min and at 1, 3, 5, 6, 8, 12, and 24 hr. Blood plasma was separated and stored at -80°C until analysis with high-performance liquid chromatography was performed to determine levels of tramadol and M1, the major active metabolite. The results indicate that the plasma levels of parent tramadol are low or negligible during the first 30-45 min and then reach the predicted mean maximum plasma concentration of 358 ng/ml at 1.52 hr. The M1 metabolite was not detectable in 21 of 24 plasma samples, below the level of quantification of 5 ng/ml in one sample, and detectable at 11 and 17 ng/ml in two of the samples. This study suggests that a 2 mg/kg dose would need to be administered every 6-8 hr to maintain concentrations of tramadol above the minimum human analgesic level for mild to moderate pain. Based on dosing simulations, a dose of 4 mg/kg q8 hr or q12 hr, on average, may represent an adequate compromise, but further studies are needed using a larger sample size. Pharmacodynamic studies are warranted to determine if tramadol provides analgesic effects in this species. The potential for tramadol toxicosis at any dose also has not been determined in this species.

Pharmacokinetics of meloxicam after intramuscular and oral administration of a single dose to American flamingos (Phoenicopertus ruber).

OBJECTIVE To determine pharmacokinetics after IM and oral administration of a single dose of meloxicam to American flamingos (Phoenicopertus ruber). ANIMALS 14 adult flamingos. PROCEDURES Flamingos were allocated to 2 groups. Each group received a dose of meloxicam (1 mg/kg) by the IM or oral route. After a 4-week washout period, groups received meloxicam via the other route of administration. Plasma meloxicam concentrations were measured with high-performance liquid chromatography. Data for each bird were analyzed. Estimated values of selected pharmacokinetic parameters were compared by use of a linear mixed-effects ANOVA. Pooled concentration-time profiles for each route of administration were analyzed to examine the influence of body weight on pharmacokinetics. RESULTS Mean ± SD maximum plasma concentration was 1.00 ± 0.88 µg/mL after oral administration. This was approximately 15% of the mean maximum plasma concentration of 5.50 ± 2.86 µg/mL after IM administration. Mean time to maximum plasma concentration was 1.33 ± 1.32 hours after oral administration and 0.28 ± 0.17 hours after IM administration. Mean half-life of the terminal phase after oral administration (3.83 ± 2.64 hours) was approximately twice that after IM administration (1.83 ± 1.22 hours). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the extent and rate of meloxicam absorption were less after oral administration than after IM administration. Intramuscular administration resulted in a short period during which mean plasma concentrations met or exceeded reported efficacious analgesic concentrations in other species, whereas oral administration did not. These results suggested that higher doses may be required for oral administration.