The antithyroid drug methimazole is widely used for the medical management of feline hyperthyroidism. Recently, custom veterinary pharmacies have offered methimazole in a transdermal gel containing pluronic and lecithin (PLO), with anecdotal evidence of efficacy. The purpose of this study was to determine the bioavailability, relative to i.v. and oral routes of administration, of transdermal methimazole in a PLO gel in cats. Six healthy adult cats were assigned to receive 5 mg of methimazole by the i.v., oral, or transdermal routes, in a randomized triple crossover protocol with 1 week washout between doses. Blood samples were taken for high performance liquid chromatography (HPLC) determination of serum methimazole, at 0, 5, 15, 30, 60 min, and 2, 4, 6, 12 and 24 h after dosing. Methimazole absorption following transdermal administration was poor and variable, with only two of six cats achieving detectable serum methimazole concentrations at any time point following transdermal administration. Area under the concentration-time curve (AUC), maximum concentration (Cmax), and absolute bioavailability were all significantly lower for the transdermal route (0.39 +/- 0.63 microg h/mL, 0.05 +/- 0.09 microg/mL, and 11.4 +/- 18.7%, respectively) than for either i.v. (7.96 +/- 4.38 microg h/mL, 3.34 +/- 2.00 microg/mL, 100%) or oral routes (2.94 +/- 1.24 microg h/mL, 0.51 +/- 0.15 microg/mL, 40.4 +/- 8.1%). The results of this study indicate generally low to undetectable bioavailability of methimazole in a lecithin/pluronic gel given as a single transdermal dose to healthy cats, although one individual cat did achieve nearly 100% transdermal bioavailability relative to the oral route.

Feline orbital aspergillosis is increasingly described in the published reports and may be an emerging disease. Orbital mycotic infections were diagnosed in three cats with exophthalmos, significant dorso-temporal globe deviation and pronounced resistance to retropulsion. Advanced imaging was performed in all three cases to evaluate the extent of disease as well as to obtain guided orbital biopsies in two cases. Surgical intervention in the form of a lateral orbitotomy was pursued in the first case with the other two cases treated with enucleation or medical management alone. The available published reports concerning sino-orbital aspergillosis are reviewed. Oral therapy with a novel triazole, voriconazole, was instituted in two cases. Although voriconazole was apparently effective against the fungal organisms, it is also resulted in adverse reactions.

Results suggest that once daily administration of methimazole was not as effective as twice daily administration in cats with hyperthyroidism and cannot be recommended for routine use.

Voriconazole has potential neurologic adverse effects in cats. Additional information regarding pharmacokinetics of the drug in this species must be gathered to help determine how it can be dosed most effectively with minimal adverse effects.

The SCRUB+PAINT protocol is associated with a decrease in the rate of postcesarean delivery infectious complications compared with using povidone-iodine topical paint alone.