OBJECTIVE To determine the plasma pharmacokinetics and safety of 1% diclofenac sodium cream applied topically to neonatal foals every 12 hours for 7 days. ANIMALS Twelve 2- to 14-day old healthy Arabian and Arabian-pony cross neonatal foals. PROCEDURES A 1.27-cm strip of cream containing 7.3 mg of diclofenac sodium (n = 6 foals) or an equivalent amount of placebo cream (6 foals) was applied topically to a 5-cm square of shaved skin over the anterolateral aspect of the left tarsometatarsal region every 12 hours for 7 days. Physical examination, CBC, serum biochemistry, urinalysis, gastric endoscopy, and ultrasonographic examination of the kidneys and right dorsal colon were performed before and after cream application. Venous blood samples were collected at predefined intervals following application of the diclofenac cream, and plasma diclofenac concentrations were determined by liquid chromatography–mass spectrometry. RESULTS No foal developed any adverse effects attributed to diclofenac application, and no significant differences in values of evaluated variables were identified between treatment groups. Plasma diclofenac concentrations peaked rapidly following application of the diclofenac cream, reaching a maximum of < 1 ng/mL within 2 hours, and declined rapidly after application ceased. CONCLUSIONS AND CLINICAL RELEVANCE Topical application of the 1% diclofenac sodium cream to foals as described appeared safe, and low plasma concentrations of diclofenac suggested minimal systemic absorption. Practitioners may consider use of this medication to treat focal areas of pain and inflammation in neonatal foals.

The objective of this study was to determine the feasibility of trephination of the frontal sinus and injection of antifungal cream using a medical bone marrow drill in dogs. Results were compared with frontal sinus trephination using a standard surgical technique. Bilateral trephination of the frontal sinuses was carried out in the heads of 11 cadavers using a medical bone marrow drill and a surgical bone chuck. The time taken to carry out the procedure using both techniques was compared. Before and after injection of antifungal cream into the frontal sinuses, computed-tomography (CT) scanning was done to assess for iatrogenic trauma and to determine the degree to which the sinuses were filled with each technique and evaluate the diffusion of the cream into the nasal cavity of each dog. The mean volume of the sinuses was 8.8 mL (3.1 to 14.3 mL). Trephination, flushing, and injecting of antifungal cream were significantly faster using the medical technique. There was no significant difference in the mean filling of the frontal sinuses between the medical (82.7%) and the surgical (82.4%) technique (P-value = 0.3). Filling of the nasal cavity was classified as very good in 6/11 cases, with evidence of trauma caused by the surgical trephination technique in 1 head. Findings suggest that use of the medical bone marrow drill is highly feasible for frontal sinus trephination. Injection of antifungal cream into the frontal sinuses using the bone marrow needle resulted in good diffusion into the ipsilateral nasal cavity and could be used to treat aspergillosis when debridement or sinusoscopy is not deemed necessary.

Objective-To determine plasma disposition after dermal application of a liposome-encapsulated formulation of lidocaine in cats. Animals-6 healthy adult cats with a mean (+/- SD) body weight of 4.1 +/- 0.44 kg. Procedure-CBC determination and biochemical analysis of blood samples were performed for all cats. Cats were anesthetized by use of isoflurane, and catheters were placed IV in a central vein. The next day, blood samples were obtained from the catheters before and 1, 2, 3, 4, 6, 8, 10, 12, and 24 hours after applying a 4% liposome-encapsulated lidocaine cream (15 mg/kg) to a clipped area over the cephalic vein. Plasma concentrations of lidocaine were analyzed with a high-performance liquid chromatography assay. Results-Two cats had minimal transdermal absorption of lidocaine, with lidocaine concentrations below the sensitivity of the assay at all but 1 or 2 time points. In the other 4 cats, the median maximum plasma concentration was 149.5 ng/ml, the median time to maximum plasma concentration was 2 hours, and the median area under the concentration versus time curve from zero to infinity was 1014.5 ng·h/ml. Conclusions and Clinical Relevance-Maximum plasma concentrations of lidocaine remained substantially below toxic plasma concentrations for cats. On the basis of these data, topical administration of a liposome-encapsulated lidocaine formulation at a dose of 15 mg/kg appears to be safe for use in healthy adult cats.