Video Otoscopy and Ear Flushing Techniques

Lynette K. Cole, DVM, MS, DACVD


            The use of video otoscopy has grown rapidly in small animal veterinary medicine.  With the aid of a video otoscope, the ear canal and tympanic membrane are brightly illuminated and magnified, allowing greater visualization.  When the video otoscope is used in the examination room, the client is also able to visualize the ear.  This allows the owner to participate in the diagnosis of the ear disease. It will also result in increased client compliance to treat the ear disease and return for scheduled re-evaluations.  The video otoscope may be used in the awake patient as well as in the sedated or anesthetized patient for ear flushing procedures. Through the opening on the otoendoscope, the ears can be flushed, foreign objects, debris, or parasites may be retrieved with grasping forceps, biopsies obtained with biopsy forceps, and myingotomy performed with a catheter.  With an attachable dual-port adapter, suction and saline may be used simultaneously to completely clean the ear.

            If video otoscopy is going to be profitable, the equipment needs to be readily available to be used on every patient seen in the practice.  If an abnormality is found during the examination, then a fee is assessed.  If there is exudate in the ear canal, then a swab specimen should be obtained for cytologic examination.

            An otic examination is performed with the video otoscope.  In some cases, a complete otic examination at the first visit is not possible because the ear canal may be stenotic, hyperplastic, edematous, and in some cases, ulcerated with secondary hemorrhage.  In addition, ears with significant amounts of debris and exudate may need to be flushed prior to examination. Therefore, prior to either ear flushing or examination, if the ears are ulcerated, hyperplastic or stenotic, 2 to 3 weeks of topical or systemic glucocorticoids are indicated.

Cytology of the otic exudates is performed to empirically start oral or topical antimicrobial agents.  Cytology is a rapid and inexpensive diagnostic procedure that is indicated in all cases of otitis.  It is the best method for detection of yeast organisms.  It should be performed at the initial examination and on all subsequent re-evaluations.  After collecting the sample from the ear canal, the swab is rolled onto a glass slide, heat fixed and stained with a modified Wright’s stain (Diff-Quik) or gram stain.  Under scanning power (100X), keratinocytes or inflammatory cells should be located.  Once those are found, immersion oil is applied to the slide and the slide is examined under oil immersion power (1000X).   The number and type of bacteria, yeast, and inflammatory cells are counted and recorded.

Bacterial culture and susceptibility testing (C/S) of otic exudates is not routinely performed at each visit.  It is reserved for chronic recurrent or unresponsive cases of otitis externa, cases with concurrent otitis media, and when cytology reveals numerous rod bacteria.

Debris in the ear canal may be irritating, mask a foreign body, serve as a nidus for infectious organisms, prevent medications from contacting the epithelium, or inactivate topical medications (gentamicin, polymyxin B).  In some cases, daily application of a cleaning/drying agent at home may be effective to remove the debris.  The proper cleaning technique is demonstrated to the client in the examination room.  However, some cases of otitis require a deep ear flushing procedure.

It is important to be familiar with the normal structures of the externa ear canal and middle ear when examining the ear and performing otic flushing.  The tympanic membrane separates the external ear canal from the middle ear.  It is a semitransparent membrane, which is thin in the center and thicker at the periphery.  The normal tympanic membrane is concave.  It is divided into two sections, the small upper pars flaccida and the larger lower pars tensa. The pars flaccida is the pink, small, loosely attached region forming the upper quadrant of the tympanic membrane that contains small blood vessels.  The pars tensa occupies the remainder of the membrane.  It is a thin, tough, pearl gray structure with radiating strands.  The pars tensa is attached firmly to the surrounding bone by a fibrocartilaginous ring.  This fibrocartilaginous ring, known as the annulus fibrocartilaginous, is attached to the osseous ring of the external acoustic meatus by fibrous tissue.  The manubrium of the malleus attaches to the medial surface of the tympanic membrane.  The outline of the manubrium of the malleus, the stria mallearis, may be visualized when the tympanic membrane is viewed externally.  The tympanic cavity may be divided into three portions.  The epitympanic recess is the smallest of the three areas.  It is occupied by the head of the malleus and the incus at their articulation. The three auditory ossicles, the malleus, incus, and stapes, are the bones that transmit and amplify air vibrations from the tympanic membrane to the inner ear.    The footplate (base) of the stapes is attached to the vestibular (oval) window, which is in direct contact with the perilymph fluid.  The tympanic cavity proper is adjacent to the tympanic membrane.  The caudal portion of this region contains the cochlear (round) window.  The auditory tube (eustachian tube) connects the nasopharynx to the rostral portion of the tympanic cavity proper.  The promontory, which houses the cochlea, lies opposite to the tympanic membrane.  The largest region of the tympanic cavity is the ventral portion, which is contained within the tympanic bulla.  Other important structures adjacent to the middle ear include the sympathetic nerve, facial nerve, vagus nerve, and the carotid and lingual arteries.    

The main functions of the inner ear are to transmit sound and maintain balance.  The inner ear consists of an osseous and membranous labyrinth.  The osseous labyrinth contains a fluid, perilymph, and encloses the membranous labyrinth, which contains its own fluid, endolymph.  The membranous labyrinth contains a series of fluid-filled ducts and chambers.  Three semicircular ducts, each in a different plane, develop from a utriculus that is connected by a duct to the sacculus.  Each semicircular duct has an ampulla that contains a sensory crista.  There are sensory maculae in the utriculus and sacculus.  Both the maculae and cristea conduct impulses for balance via the vestibular nerve.  The most highly developed portion of the membranous labyrinth is the cochlear duct.  Within the cochlear duct lies the organ of Corti, tectorial membrane, vestibular membrane, and sensory cells, all of which are involved in the transduction and transmission of sound impulses via the cochlear nerve to the brain.  The bony labyrinth surrounds the membranous labyrinth and consists of a perilymphatic space or vestibule, three semicircular canals, and a spiral cochlea.

 The deep ear flushing procedure is best done under general anesthesia to completely clean and evaluate the ear.  If otitis media is suspected, bulla radiographs or computed tomography (CT) are indicated to evaluate the soft tissue structures of the external and middle ear along with the osseous structures of the middle ear.  These procedures are performed prior to the ear flush.  For the ear flush, the external ear canal is soaked for 10 minutes with a ceruminolytic ear cleaner.  The ear is then flushed with warm sterile isotonic saline and a bulb syringe to remove large debris and exudate.  This is followed by flushing with saline using an 8 French polypropylene urinary catheter attached to a 12 cc syringe passed through an otoscopic cone.  Additional ear cleaning is performed using the video otoscope with the dual-port adapter, saline, and suction.  Once the ear is clean, the tympanic membrane is visualized utilizing the video otoscope.  The ear canal is then dried using an open-end Tom cat catheter attached to a 12 cc syringe passed through the port on the otoendoscope.  If the tympanic membrane is not intact, bacterial C/S is performed from the middle ear cavity.  This is performed by passing an open-end Tom cat catheter attached to a 12 cc syringe through the port on the otoendoscope into the middle ear cavity.  Saline is flushed into the middle ear cavity and aspirated back and the fluid is cultured.  The middle ear is then flushed repeatedly with saline using an open-end Tom cat catheter attached to a 12 cc syringe passed through the port on the otoendoscope to completely remove any ear cleaner to reduce the chance of ototoxicity. 

            If the tympanic membrane is intact, appears abnormal, and otitis media is suspected, a myringotomy is needed to obtain samples for cytology and bacterial C/S, and to flush the middle ear cavity. This can be done using an open-end Tom cat catheter.  The Tom cat catheter is guided through the port of the otoendoscope, and is used to make the incision. Saline is flushed into the middle ear cavity and aspirated back using a 12 cc syringe attached to the open-end Tom cat catheter. The fluid is then cultured. The middle ear is flushed through the incision with saline using an open-end Tom cat catheter attached to a 12 cc syringe passed through the port on the otoendoscope.  The normal tympanum heals in 21 to 35 days.  Therefore, if the ear is kept free of infection after the myringotomy procedure, the tympanic membrane should heal.  Possible complications of ear flushing and myringotomy are Horner’s syndrome, facial nerve paralysis, vestibular disturbances, and deafness. Owners should understand these complications and sign a consent form prior to the procedure.

            Once the ear has been cleaned, appropriate medications should be started based on the results from cytology.  The medications may be modified once the culture results are back.  In addition, further diagnostics to evaluate the patient for the underlying primary cause of the otitis should be performed, along with controlling any predisposing factors. 

Otic Therapy

            Ceruminolytic Agents  

            Ceruminolytic agents are needed to remove ceruminous and purulent exudate from the external ear canal during the ear flushing procedure.  Some of these products may be used at home by the client.  They work by surfactant, detergent, or bubbling activity.  These products are contraindicated with a ruptured tympanic membrane, but are still used in the sedated or anesthetized dog during an ear flushing procedure if needed followed by multiple flushes with warm sterile isotonic saline.  Water miscible preparations containing dioctyl sodium sulfosuccinate (DSS) or propylene glycol are well tolerated.  Oils, such as squalene or mineral oil are effective, however messy, ceruminolytic agents.  Products containing urea peroxide are very potent and recommended for in-hospital usage only.

Pan-Otic (Pfizer Inc)
Ingredients: Purified water, isopropyl alcohol, aloe vera, diazolidinyl urea, methylparaben, dioctyl sodium sulfosuccinate, octoxynol, sodium lauryl sulfate, parachlorometaxylenol, propylene glycol

ADL Ear Cleanser(ADL) 
Ingredients: Cocamidopropyl betaine, peg almond glycerides, almond glycerides, isostearamidopropyl morpholine lactate, salicylic acid, eucalyptol

Cerulytic (Virbac Corporation) 
Ingredients: Benzyl alcohol, butylated hydroxytoluene, propylene glycol base

Cerumene (EVSCO Pharmaceuticals) 
Ingredients: 25% squalene in isopropyl myristate liquid petrolatum base

CLEARx Ear Cleansing Solution (DVM Pharmaceuticals)  Ingredients: 6.5% dioctyl sodium sulfosuccinate, 6% urea peroxide

Corium-20 (Virbac Corporation) 
Ingredients: Purified water, SDA-40B 23%, glycerol

Earoxide Ear Cleanser (Tomlyn Products)
Ingredients: 6.5% carbamide peroxide in a glycerin base

OtiFoam (DVM Pharmaceuticals)
Ingredients: Water, cocamidopropyl betaine, PEG-60 almond glycerides, mackalene 426, salicylic acid, oil of eucalyptus

Ear Cleaning/Drying Agents     

            Once the debris and exudate have been removed from the external ear canal with a ceruminolytic agent, a cleaning and drying agent is applied.  They usually contain some type of acid or isopropyl alcohol.  These products may also be used after swimming or bathing to prevent swimmer’s ear.  Cleaning and drying agents are also useful in a maintenance ear program to keep infections from recurring.  The use of an ear cleaner as a treatment for bacterial and yeast otitis externa is currently under investigation.

  1. Ace-Otic Cleanser (Vetus Animal Health)                                    
    • Ingredients: Acetic acid, lactic acid, salicylic acid in a surface-active vehicle containing docusate and propylene glycol
  2. ADL Ear Flushing Drying Lotion (ADL)                
    • Ingredients: Isopropyl alcohol, salicylic acid, eucalyptol, acetamide MEA, propylene glycol, acetic acid, aluminum acetate, hydrolyzed oat protein, wheat amino acids
  3. DermaPet Ear/Skin Cleanser for Pets (DermaPet Inc)      
    • Ingredients: Acetic acid, boric acid, surfactants
  4. Epi-Otic Cleanser with Spherulites (Virbac Corporation)    
    • Ingredients: Lactic acid and salicylic acid are present in encapsulated and free forms, chitosanide is present in encapsulated form, in docusate sodium and propylene glycol base
  5. Euclens Otic Cleanser (Vetus Animal Health)                                                      
    • Ingredients: Propylene glycol, malic acid, benzoic acid, eucalyptus oil
  6. Fresh-Ear (Q. A. Laboratories)                                                               
    • Ingredients: De-ionized water, isopropyl alcohol, propylene glycol, glycerine, fragrance, salicylic acid, PEG 75 lanolin oil, lidocaine hydrochloride, boric acid, acetic acid
  7. Gent-L-Clens (Schering-Plough Animal Health Corporation)                                                           
    • Ingredients: Lactic acid, salicylic acid in propylene glycol
  8. Oticalm (DVM Pharmaceuticals)                                                            
    • Ingredients: Benzoic acid, malic acid, salicylic acid, oil of eucalyptus
  9. Otic Clear (The Butler Company)                                                            
    • Ingredients: Deionized water, isopropyl alcohol, propylene glycol, glycerine, fragrance, salicylic acid, PEG 75 lanolin oil, lidocaine hydrochloride, boric acid, acetic acid
  10. Oti-clens (Pfizer Inc)                                                                  
    • Ingredients: Propylene glycol, malic acid, benzoic acid, salicylic acid
  11. OtiRinse (DVM Pharmaceuticals)
    • Ingredients: Water, propylene glycol, SD alcohol 40, DSS, glycerine, nonoxynol-12, salicylic acid, benzoic acid, benzyl alcohol, fragrance, aloe vera 
  12. Otocetic Solution (Vedco, Inc)                                        
    • Ingredients: 2% boric acid, 2% acetic acid, surfactants

Topical Antiseptics

            Topical antiseptics such as acetic acid and chlorhexidine have been used in cases of otitis.  Acetic acid works by acidification and other mechanisms as an antimicrobial agent.  A 2% solution is effective against Pseudomonas.  Products containing acetic acid include:

  1. Ace-Otic Cleanser (Vetus Animal Health)
    • Ingredients: Acetic acid, lactic acid, salicylic acid in a  surface-active vehicle containing docusate and propylene glycol
  2. AloCetic (DVM Pharmaceuticals)
    • Ingredients: Acetic acid, aloe                 
  3. Bausch & Lomb Acetic Acid 2% in Aqueous Aluminum    
  4. Acetate Otic Solution (Bausch and Lomb)
    • Ingredients: Acetic acid, aluminum acetate
  5. Bur-Otic (Virbac Corporation)
    • Ingredients: Propylene glycol, water, burow’s solution, acetic acid, benzalkonium chloride  
  6. Clearx Ear Drying Solution (DVM Pharmaceuticals)
    • Ingredients: Acetic acid, colloidal sulfur, hydrocortisone
  7. DermaPet Ear Cleanser (DermaPet Inc)
    • Ingredients: Acetic acid, boric acid, surfactants
  8. Fresh-Ear (Q. A. Laboratories)                                                               
    • Ingredients: De-ionized water, isopropyl alcohol, propylene glycol, glycerine, fragrance, salicylic acid, PEG 75 lanolin oil, lidocaine hydrochloride, boric acid, acetic acid
  9. Otic Clear (The Butler Company)                                                            
    • Ingredients: Deionized water, isopropyl alcohol, propylene glycol, glycerine, fragrance, salicylic acid, PEG 75 lanolin oil, lidocaine hydrochloride, boric acid, acetic acid
  10. Otocetic Solution (Vedco, Inc)
    • Ingredients: 2% boric acid, 2% acetic acid, surfactants

            Chlorhexidine has broad spectrum activity against many gram-positive and gram-negative bacteria and fungi; however, Pseudomonas may be resistant.  Chlorhexidine may be ototoxic and should be used with caution or not at all in ears with ruptured tympanic membranes.  However, a recent study done in normal greyhounds with experimentally ruptured tympanic membranes treated twice a day for 21 days with a topical application of 0.2% chlorhexidine failed to show any clinical vestibular or brainstem auditory evoked potential changes. Nolvasan Otic (Fort Dodge Animal Health) no longer contains chlorhexidine.  Chlorhexidine-containing products include:

  1. ChlorhexiDerm Flush (DVM Pharmaceuticals)
    • Ingredients: Chlorhexidine gluconate
  2. Hexadene Flush (Virbac Corporation)
    • Ingredients: Water, propylene glycol, 0.25% chlorhexidine gluconate, triclosan, fragrance
Topical Otic Therapy

            In most cases of otitis, specific topical therapy is indicated.  The topical otic preparations usually contain various combinations of glucocorticoids, antibiotics, and antifungals in a vehicle base.  For dry lesions, an oil or ointment base product is used to help moisturize the skin, while in moist lesions a solution or lotion is recommended.  The patient’s progress while on these medications should be monitored cytologically at each re-evaluation and the topical therapy adjusted accordingly.

Glucocorticoids  

            Glucocorticoids are antipruritic, anti-inflammatory, and antiproliferative.  During the acute stage of otitis, the ear canal becomes edematous and erythematous.  As the inflammation progresses, the dermis becomes infiltrated with a mixed population of cells.  Apocrine glands dilate and become hyperplastic, which leads to excessive cerumen production.  Therefore, glucocorticoids are beneficial in decreasing the pain, pruritus, stenosis, and edema associated with otitis.  In addition, they are effective in decreasing sebaceous and apocrine secretions.  They are usually in combination with other agents but may be beneficial when used alone in allergic cases of otitis and some ceruminous otitis cases. It is important to use the lowest potency glucocorticoid at the lowest frequency needed to control the otitis to prevent iatrogenic hyperadrenocorticism. 

            Synotic contains dimethyl sulfoxide (DMSO) in addition to a very potent glucocorticoid, fluocinolone acetonide.  DMSO is anti-inflammatory and facilitates the absorption of fluocinolone into the epidermis and dermis.  It is very effective in the management of proliferative otitis.

  1. Buro-O-Cort 2:1 (Q. A. Laboratories)                                                       
    • Ingredients: Burow’s solution, hydrocortisone in a water miscible propylene glycol base
  2. Bur-Otic HC (Virbac Corporation)                                                
    • Ingredients:1% hydrocortisone, propylene glycol, water, burow’s solution, acetic acid, benzalkonium chloride
  3. CLEARx Drying Solution (DVM Pharmaceuticals)                                    
    • Ingredients: Acetic acid, colloidal sulfur, hydrocortisone               
  4. Cort/Astrin Solution (Vedco, Inc)                                    
    • Ingredients: Burow’s solution, 1% hydrocortisone
  5. Synotic Otic Solution (Fort Dodge Animal Health)                                    
    • Ingredients: 0.01% fluocinolone acetonide, 60% DMSO

Antibiotic Agents

            Topical aminoglycosides such as neomycin and gentamicin have good activity against gram positive and gram negative otic pathogens but ototoxicity is a concern.  Gentamicin and neomycin are available in many combination products, some which contain an antifungal and glucocorticoid.

  • Derma 4 Ointment (Pfizer Inc)
    • Ingredients: Nystatin, neomycin sulfate, thiostrepton, triamcinolone acetonide
  • Dermagen Ointment (The Butler Company)
    • Ingredients: Nystatin, neomycin sulfate, thiostrepton, triamcinolone acetonide
  • Dermalone Ointment (Vedco, Inc)                                               
    • Ingredients: Nystatin, neomycin sulfate, thiostrepton,  triamcinolone acetonide
  • Gentocin Ophthalmic (Schering-Plough Animal Health Corporation)                                               
    • Ingredients: Gentamicin sulfate
  • Gentocin Otic Solution (Schering-Plough Animal Health Corporation)                                             
    • Ingredients: Gentamicin sulfate, betamethasone valerate
  • Otomax (Schering-Plough Animal Health Corporation)                                                                  
    • Ingredients: Gentamicin sulfate, betamethasone valerate, clotrimazole
  • Panolog Cream and Ointment (Fort Dodge Animal Health)                        
    • Ingredients: Nystatin, neomycin sulfate, thiostrepton, triamcinolone acetonide
  • Quadritop Ointment (Vetus Animal Health)
    • Ingredients: Nystatin, neomycin sulfate, thiostrepton, triamcinolone acetonide
  • Topagen Ointment (Schering-Plough Animal Health Corporation)                                       
    • Ingredients: Gentamicin sulfate, betamethasone valerate
  • Tresaderm (Merial)                                                                    
    • Ingredients: Thiabendazole, dexamethasone, neomycin sulfate
  • Tritop (Pharmacia & Upjohn Company)                                                                
    • Ingredients: Neomycin sulfate, isoflupredone acetate, tetracaine hydrochloride

            Another aminoglycoside, tobramycin, is available as an ophthalmic solution with or without dexamethasone and appears to be very effective against Pseudomonas otitis infections.  Both these products are very expensive; however, there is a generic for Tobrex  which is less expensive.

  • TobraDex Ophthalmic Solution (Alcon Laboratories, Inc)               
    • Ingredients: Tobramycin and dexamethasone
  • Tobrex Ophthalmic Solution (Alcon Laboratories, Inc)                               
    • Ingredients: Tobramycin

            Chloramphenicol has good activity against most otic pathogens except Pseudomonas.  Owners should be advised of idiosyncratic bone marrow suppression from contact with topical chloramphenicol.

  • Liquichlor (EVSCO Pharmaceuticals)      
    • Ingredients: Chloramphenicol, prednisolone, tetracaine with squalene

            Fluoroquinolones have a broad spectrum of antibacterial activity against gram negative and gram positive bacteria.   Topical fluoroquinolones are available as human otic (FLOXIN Otic, Daiichi Pharmaceutical Corp) and an ophthalmic preparation (CILOXAN, Alcon Laboratories, Inc) and in a veterinary otic preparation.  The veterinary fluoroquinolone otic preparation (Baytril Otic, Bayer Corporation, Agricultural Division, Animal Health) contains 0.5% enrofloxacin and 1% silver sulfadiazine.  

            Polymyxin has excellent in vitro activity against Pseudomonas with resistance rarely developing.  Polymyxin is inactivated in purulent debris so the ear needs to be kept clean during treatment. There are several generic neomycin and polymyxin B combinations with or without hydrocortisone.  Polymyxin may be found in the following products:

  • Neomycin, polymyxin B, and hydrocortisone (generics)
  • Otobiotic (Schering-Plough Animal Health Corporation)
    • Ingredients: Polymyxin B, hydrocortisone

            Tris-EDTA is a topical product that enhances the activity of topical antibiotics against otic pathogens by decreasing stability and increasing the permeability of the cell wall of the bacteria.  The product works best when applied to the external ear canal 15-30 minutes before the topical antibiotic.  Tris-EDTA may be compounded by a pharmacist using 1.2 g EDTA, 6.05 g Tris buffer, 1 L distilled water, ph 8; autoclave 15 minutes.   There is now a commercial preparation on the market (Triz-EDTA, DermaPet Inc).

Antifungal Agents  

            Antifungal agents are used in cases of otitis caused by Malassezia or Candida.  Ingredients that are active against yeast include nystatin, thiabendazole, miconazole, and clotrimazole.

  • Clotrimazole Solution (VET Solutions)
    • Ingredients: Clotrimazole 1%, chloroxylenol
  • Conofite Lotion (Schering-Plough Animal Health Corporation)                                                        
    • Ingredient:Miconazole nitrate 1%
  • Derma 4 Ointment (Pfizer Inc)                                       
    • Ingredients: Nystatin, neomycin sulfate, thiostrepton, triamcinolone acetonide
  • Dermagen Ointment (The Butler Company)                                              
    •  Ingredients: Nystatin, neomycin sulfate, thiostrepton, triamcinolone acetonide
  • Dermalone Ointment (Vedco, Inc)                                               
    • Ingredients: Nystatin, neomycin sulfate, thiostrepton,  triamcinolone acetonide
  • Otomax (Schering-Plough Animal Health Corporation)
    • Ingredients: Gentamicin sulfate, betamethasone valerate, clotrimazole
  • Panolog Cream and Ointment (Fort Dodge Animal Health)                        
    • Ingredients: Nystatin, neomycin sulfate, thiostrepton, triamcinolone acetonide
  • Quadritop Ointment (Vetus Animal Health)                                              
    • Ingredients: Nystatin, neomycin sulfate, thiostrepton, triamcinolone acetonide
  • Tresaderm (Merial)                                                                    
    • Ingredients: Thiabendazole, dexamethasone, neomycin sulfate

Extra-label Preparations   

            An extra-label topical preparation may be formulated using 1 part of the injectable enrofloxacin (22.7 mg/ml) added to 4 parts of an appropriate vehicle, such as Synotic, 1% hydrocortisone, or saline.  There have been no reports of clinical ototoxicity with this formulation; however, toxicity studies have not been conducted.  It appears to be very effective for treatment of Pseudomonas otitis infections.   

            Silver sulfadiazine 1% (Silvadene Cream 1%, Hoechst Marion Roussel, Inc) is available in a cream formulation.  0ne part of the Silvadene cream can be mixed with 9 parts water prior to application in the ear.  This product is safe and appears non-ototoxic.  However, contact hypersensitivity or irritancy may occur on rare occasions.  It has been shown to be very effective against resistant Pseudomonas.

            Injectable ticarcillin is a semisynthetic, betalactamase-susceptible penicillin.   In humans, it is active against most isolates of Pseudomonas and some Proteus species.  It is ineffective against Staphylococcus infections.  In dogs, it may be formulated into a solution for topical application into the ear for susceptible Pseudomonas otitis infections by taking 30 ml sterile water and adding it to a 3 g bottle of Ticarcillin.  Then take 1.8 cc of the mixture and add 88.2 ml propylene glycol.  Refrigerate and shake well before using.  Appears to be stable for 2 weeks.

            For inflamed ears with yeast otitis without a bacterial component, topical antifungals, such as Clotrimazole Solution and Conofite Lotion may be mixed 1:1 with dexamethasone.  Ketoconazole 200 mg tablets may be crushed (1 1/2 tablets) and mixed with Bur-Otic HC.  Prior to use in the ear, this preparation needs to be shaken well to mix the contents, since the crushed tablets will settle out of solution.