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Ototopical antibiotics: When should they be used?
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Numerous otic products are available to treat a variety of infectious, inflammatory and discomforting ear conditions in children. These products may contain antibiotics, antifungals, corticosteroids, acidifying agents, antiseptics or local analgesics, among other ingredients. Several of these products are indicated to treat acute tympanostomy tube otorrhea. Recent studies comparing topical otic antibiotic preparations with oral antibiotics for treatment of acute tympanostomy tube otorrhea have been published, and the American Academy of Otolaryngology – Head and Neck Surgery has also recently published a clinical practice guideline on tympanostomy tubes in children. These ototopical antibiotic and antibiotic/corticosteroid products will be discussed in this month’s column.
Otic vs. oral antibiotics
In early 2014, van Dongen and colleagues published a non-masked, randomized controlled trial that compared hydrocortisone-bacitracin-colistin ear drops with oral amoxicillin/clavulanate, or observation, in children with acute tympanostomy tube otorrhea. A total of 230 children from the Netherlands (aged 1 to 10 years) with tympanostomy tube otorrhea with a duration of up to 7 days were included. The primary outcome measure was the presence of otorrhea 2 weeks after initiation of treatment. Children who received antibiotic/corticosteroid ear drops met the primary outcome more frequently than children who received oral antibiotics or observation — at 2 weeks, 5% of children on antibiotic/corticosteroid ear drops had otorrhea, as compared with 44% and 55% of children on amoxicillin/clavulanate and observation, respectively (P<.05). Although the ear drop product used in this study is not available in the United States, it is similar to other ototopical antibiotic/corticosteroid products that are available here. The dose of amoxicillin/clavulanate used in this study — 30 mg/kg/day, less than doses commonly used in the United States — was chosen to match lower antimicrobial resistance rates in the Netherlands.
Several controlled trials similar to van Dongen’s study have been published that compared ototopical antibiotic products (products containing the fluoroquinolone antibiotics ciprofloxacin or ofloxacin) with oral antibiotics (amoxicillin or amoxicillin/clavulanate). These trials also found ototopical antibiotic products to be superior to oral antibiotics.
Edward A. Bell
Use of ototopical antibiotics may be more effective because they can achieve significantly higher antibiotic concentrations (100 to 1,000 times higher) at the site of infection, and, when fluoroquinolone-containing products are used, they provide enhanced antibacterial activity toward Pseudomonas aeruginosa and Staphylococcus aureus, which is not often provided by oral antibiotics commonly used to treat ear infections in children. These, and other important issues, are well described in a recently published guideline, Clinical Practice Guideline: Tympanostomy Tubes in Children, by the American Academy of Otolaryngology – Head and Neck Surgery (2013).
The clinical practice guideline states: “Clinicians should prescribe topical antibiotic eardrops only, without oral antibiotics, for children with uncomplicated acute tympanostomy tube otorrhea.” Acute, uncomplicated otorrhea is defined as otorrhea of less than 4 weeks’ duration, and without high fever (≥38.5°C), concurrent illness requiring systemic antibiotics or cellulitis extending beyond the external ear canal. Furthermore, these guidelines recommend that only eardrops that are labeled for use in children to treat tympanostomy tube otorrhea are to be used, namely ofloxacin- or ciprofloxacin-containing products (see Table). Oral or systemic antibiotics may be added to, or replace, ototopical antibiotics if cellulitis of the pinna or surrounding skin occurs, with concurrent bacterial infection (such as sinusitis), severe infection, failure of ototopical therapy, when ototopical application is not tolerated, or in children with immunocompromising conditions.
Effect of non-fluoroquinolone antibiotics
Otopical antibiotic preparations containing non-fluoroquinolone antibiotics are also available to treat infections of the ear in children, including aminoglycosides (eg, neomycin, tobramycin), colistin or polymyxin B. However, these products are labeled for use only to treat infections of the external auditory canal, namely acute otitis externa (eg, Coly-Mycin S [JHP Pharmaceuticals], Cortisporin).
Until the fluoroquinolone-containing otic products became available more than 20 years ago, aminoglycoside products had been used when a non-intact tympanic membrane was present. As the aminoglycoside antibiotics can display ototoxicity when given systemically, this adverse effect and toxicity had been a concern when ototopical drops containing an aminoglycoside were applied into the middle ear space. However, there are significant data from animal studies that demonstrated ototoxicity when aminoglycosides are applied to the middle ear space, although how these data relate to humans is not clear. Clinical experience with aminoglycoside-containing ototopical drops, when given to children with a non-intact tympanic membrane, does not seem to indicate toxicity when a short course of therapy is used. However, significant toxicity — hearing loss — has been reported when longer courses are used or when excessive doses are administered. Although these data have come from non-controlled reports, they remain important. Thus, published guidelines recommend against the use of aminoglycoside-containing antibiotic ototopical preparations in children, when the tympanic membrane is perforated and the middle ear space is open.
Several ototopical antibiotic products additionally contain a corticosteroid agent (dexamethasone or hydrocortisone). The 2013 Clinical Practice Guideline on tympanostomy tubes in children states that an ototopical antibiotic product combined with a corticosteroid can be used when granulation tissue is present at the junction of the tympanostomy tube and tympanic membrane. Several controlled trials have demonstrated that addition of a topical corticosteroid agent to an ototopical antibiotic can improve clinical cure rates in children with acute otitis media and otorrhea through tympanostomy tubes. Persistent, painless otorrhea that is bloody in appearance, or pinkish in color, may indicate the presence of granulation tissue.
Products that contain a fluoroquinolone antibiotic and hydrocortisone or dexamethasone are available for use (see Table). Although hydrocortisone is a less-potent glucocorticoid agent than dexamethasone, products with this glucocorticoid contain a higher concentration than products containing dexamethasone.
Proper administration of ototopical antibiotics
When prescribing ototopical antibiotic products, it is important to consider appropriate administration and efficient application of instillation of liquid solution or suspension products into the ear canal. An ear canal that is occluded with discharge, pus or debris can significantly impede and diminish antibiotic solution penetration into infected areas. Guidelines describe blotting the ear canal or use of an infant nasal aspirator to clean secretions and debris. Cotton swabs moistened with hydrogen peroxide can be used to clean dried material in the ear canal. Additional measures include pumping the child’s tragus by a caregiver after drop installation into the canal to help ensure drop mobilization into the middle ear.
Proper administration of antibiotic drops is also important for acute otitis externa — drops should be applied to the child lying down and the ear positioned upward. Drops can then be placed along the side of the ear canal until it is filled. A gentle massage of the pinna can help mobilize applied drops into the canal. The Clinical Practice Guideline: Acute Otitis Externa (2006) can be referenced for more information on the use of aural toilet and wicks to further assist with administration of antibiotic drops.
Rosenfeld RM. Otolaryngol Head Neck Surg. 2006;134(4 suppl):S4-S23.
Edward A. Bell, PharmD, BCPS, is professor of pharmacy practice at Drake University College of Pharmacy and Health Sciences and Blank Children’s Hospital and Clinics, Des Moines, Iowa. Bell can be reached at ed.bell@drake.edu.
Disclosure: Bell reports no relevant financial disclosures.