OBJECTIVES: Retreatment of acute infections can often be high thereby increasing treatment costs. This study examined the retreatment rates of acute otitis media in patients with tympanostomy tubes (AOMT) within the Louisiana Medicaid population. METHODS: Louisiana Medicaid claims data for 2000-2002 were retrospectively reviewed for episodes of AOMT. Tympanostomy tube (t-tube) patients were identified using CPT codes from an index period of January 1, 2000 through June 30, 2000. AOMT patients were followed for 24 months from their respective index dates. Episodes of AOMT were then identified from the t-tube sample group using ICD-9-CM codes. An episode started with the first antibiotic claim between one day before or two days after an ICD-9-CM code for AOMT and ended 21 days later. Retreatment was defined as the presence of another antibiotic claim between days 3 and days 21 of an episode of care. Only antibiotics commonly used in the treatment of AOMT were considered in the retreatment analysis. Retreatment rates were calculated on an overall (per episode) basis and by antibiotic. RESULTS: There were 5934 episodes of AOMT care identified within the dataset of which 1381 required retreatment resulting in an overall retreatment rate of approximately 23%. Some of the antibiotics commonly prescribed in the treatment of AOMT are presented in rank order relative to their retreatment rates: ciprofloxacin HCL and hydrocortisone (12%), cephalexin (17%), ofloxacin (26%), amoxicillin (28%), amoxicillin potassium clavulanate (32%), sulfamethoxazole trimethoprim (32%), azithromycin (32%), clarithromycin (33%), cefdinir (33%), and cefprozil (36%). CONCLUSIONS: The retreatment rate of AOMT in the Louisiana Medicaid population was high with approximately 1 out of 4 episodes requiring retreatment. Retreatment rates also varied considerably between antibiotic therapies. Careful consideration of AOMT antibiotic therapy by clinicians may reduce retreatment rates thereby lowering the associated cost of AOMT treatment in the Louisiana Medicaid program.