Objectives: To determine the in vitro persistence of clotrimazole 1% cream in the canine frontal sinus and to evaluate the distribution of clotrimazole solution over the sino-nasal mucosa using a previously described surgical treatment protocol for canine nasal aspergillosis.

Methods: Two canine skulls were used to monitor the persistence of clotrimazole cream in the lateral frontal sinus at 37°C. The distribution of irrigation solution around the frontal sinus compartments and nasal cavity was determined using six canine cadaver heads by trephining either the lateral or both the lateral and rostral compartments of the frontal sinus. Stain was added to the sinus irrigation solution before visually inspecting the sagittally sectioned heads.

Results: Clotrimazole cream persisted in the frontal sinus for at least 96 hours. The nasal cavity mucosa was completely stained in 8 of 12 sides and almost completely stained in the remaining 4 of 12 sides. Flushing irrigation solution through the lateral compartment of the frontal sinus resulted in inadequate staining of the rostral compartment but medicating both the lateral and rostral compartments resulted in complete coating of all frontal sinus mucosa in eight of eight sides.

Clinical Significance: Clotrimazole cream has the potential to be retained in the frontal sinus for several days and is distributed effectively in normal canine cadavers. Medicating both the rostral and lateral compartments of the frontal sinus may be indicated in some clinical cases.