Dr. Greene's Answer
The change to high-dose amoxicillin came because many bacteria were getting partially resistant to it. Rather than switching to antibiotics that are broader spectrum or with more side effects, high-dose amoxicillin is considered the most effective and safest of the first-line treatments.
The recommended dosage used to be 10 to 30 mg per kg of body weight per day. But for ear infections, it is now better to give 80 to 90 mg per kg per day. For her, that would be somewhere between 750 and 1000 mg daily. The timing between doses does not need to be precise, but the farther apart the doses are, the lower the chances of diarrhea as a side effect.
Generally speaking, amoxicillin is a very safe and well-tolerated medication, even at the higher doses. However, antibiotics do kill beneficial bacteria as well, and the more effective the antibiotic, the more likely this will happen. Eating yogurt with active cultures is a great way to replenish them. Some of the frozen varieties are the most effective.
References and Resources
Lieberthal AS, et al. The diagnosis and management of acute otitis media [published correction appears in Pediatrics. 2014 Feb;133(2):346. Dosage error in article text]. Pediatrics. 2013;131(3):e964-e999. doi:10.1542/peds.2012-3488
Venekamp RP, et al. Antibiotics for acute otitis media in children. Cochrane Database Syst Rev. 2015;2015(6):CD000219. doi:10.1002/14651858.CD000219.pub4