THERAPEUTICS
Drug pharmacokinetics are discussed in Chapter 11 and a drug formulary is provided in Appendix 4. Additional information is available in Blyde and Vogelnest (2008).
3.1. Cefovecin
Pharmacokinetic studies demonstrated that a single IM dose of cefovecin at 8 mg/kg in two common bottle-nosed dolphins provided therapeutic levels for up to 17 d (Gar- cia-Parraga et al.
2010). This is potentially useful because the spectrum of bacterial susceptibility to cefovecin matches the common pathogens found in cetaceans. In particular, cefovecin is indicated for the treatment of Pseudomonas spp. infections, a common opportunistic pathogen in managed and free-ranging cetaceans.3.2 Antifungal drugs
Voriconazole and posaconazole are triazole antifungal drugs that have been used successfully to treat systemic fungal infections in cetaceans (Ferrier et al. 2017; Wells et al. 2012) (see Appendix 4).
3.3 Analgesics
Analgesic drugs used in cetaceans include tramadol, butorphanol, pethidine, flunixin meglumine and melox- icam (see Appendix 4). Tramadol may produce mild sedation. Opioids may elicit excitement in some cetaceans when given alone and are generally used in combination with a benzodiazepine. Opioid antagonists should be available in the event of excessive excitement. NSAIDs should be used with caution because adverse effects include GI ulceration and acute renal failure. Flunixin meglumine and meloxicam should ideally be used as a one-off dose. In common bottle-nosed dolphins the elimination half-life of meloxicam after a single oral dose of 0.1 mg/kg is 70 hr, with detectable drug concentrations up to 7 d. Although meloxicam appears safe in this species, repeated dosing must be used with caution until multi-dose pharmacokinetics are determined (Simeone et al. 2014). Weekly dosing appears safe if repeat dosing is required.
If meloxicam is used for more than one dose the blood urea nitrogen and creatinine levels should be monitored and drug administration ceased if levels rise. Concurrent therapy with misoprostol at 200 μg qid PO can be used to prevent gastric ulceration when NSAIDs are used.Piroxicam is a non-selective cyclooxygenase (COX) inhibitor that has successfully been used alone and in combination with cytotoxic drugs to treat many neoplastic conditions, including squamous cell carcinomas in domestic animals (Schmidt et al. 2001) and cetaceans (March et al. 2016). It is also a useful anti-inflammatory and analgesic drug. Given that piroxicam and meloxicam are similar, it should also be used with caution, as it may also have a long elimination half-life with similar side effects to those observed with meloxicam (March et al. 2016).
Fig. 46.3. Location of superficial blood vessels in dolphin species. Illustration: Mark Blyde
3.4 Stem cell therapy
Adipose-derived stem cells are multipotent mesenchymal stem cells with the potential for tissue repair and regeneration. Johnson et al. (2012) demonstrated that stem cells enhance epidermal wound healing in bottle-nosed dolphins and may be a clinically useful product to augment treatment in a variety of pathological conditions in cetaceans.
3.5 Intravenous fluid administration
Intravenous fluids can be administered via the tail fluke veins or superficial caudal peduncle vein (Figs 46.3 and 46.4). Cannulation is best achieved using ultrasound guidance and a Micropuncture® introducer set (Cook Medical, Bloomington, IN, USA) (Ivancic et al. 2015).
4.