Pharmacokinetics of hydromorphone hydrochloride after intravenous and intramuscular administration in guinea pigs (Cavia porcellus)

Pharmacokinetics of hydrorphone hydrochloride after intravenous and subcutaneous administration in ferrets (Mustela putorius furo)

OBJECTIVE

To determine the pharmacokinetic profile of hydromorphone 0.2 mg kg-1 administered by the intravenous (IV) and subcutaneous (SC) route in ferrets.

STUDY DESIGN

Randomized, crossover study.

ANIMALS

A group of eight adult ferrets weighting (mean ± standard deviation) 1.02 ± 0.22 kg.

METHODS

Hydromorphone hydrochloride 0.2 mg kg-1 was administered IV or SC with a washout period of 7 days. Blood samples were collected from a jugular catheter before administration of hydromorphone and at 5, 10, 15, 20, 30, 45, 60, 90, 120, 240, 360, 480 and 720 minutes after hydromorphone administration. Plasma hydromorphone concentrations were determined by liquid chromatography/tandem mass spectrometry. Data were analyzed using a non-linear mixed effects model.

RESULTS

The hydromorphone effective half-life was (t1/2) 45 min-1. Systemic clearance (Cls) and the volume of distribution (Vdss) following IV administration were 84.8 mL kg-1 min-1 and 5.59 L kg-1, respectively. The maximum observed plasma concentration was 59.53 ± 14.02 ng mL-1 within 10 minutes following SC administration. The SC bioavailability was 102.0%.

CONCLUSIONS AND CLINICAL RELEVANCE

Administration of IV and SC hydromorphone (0.2 mg kg-1) was characterized by a high clearance, short terminal half-life and large volume of distribution. Hydromorphone plasma concentrations remained greater than 2 ng mL-1 for 2 hours in most ferrets, a threshold reported to provide antinociceptive effects in other species. Hydromorphone was well absorbed following SC injection, providing an alternative administration route for clinical use in ferrets.

Sedation and Anesthesia in Exotic Animal Critical Care

Sedation and anesthesia of exotic animals in inherently challenging, but often facilitates the best care for patients. Critical illness or injury adds on another layer of complexity to their management for obtaining diagnostics and providing treatments. This article serves to review some of the more recent literature of sedation and anesthesia within exotics practice, bringing to light some nuances and considerations for when those patients are critically ill or injured.

Hystricomorph Rodent Analgesia

Limited information on the analgesic efficacy and safety of even clinically commonly used analgesic drugs in guinea pigs and chinchillas is available. Buprenorphine and meloxicam are currently the most common analgesics routinely used to treat painful conditions in guinea pigs and chinchillas. Hydromorphone has also shown to be an effective analgesic drug in these species, with limited adverse effects. Tramadol in chinchillas does not provide analgesia even at high doses, and no information is available on the efficacy of this drug in guinea pigs. Multimodal analgesic protocols should be considered whenever possible.

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