Amoxicillin is the first-choice antibiotic for most ear infections. It works against the bacteria that cause the majority of middle ear infections, it’s inexpensive, and it has decades of clinical use behind it. But the right antibiotic depends on the type of ear infection you have, whether you’re allergic to penicillin, and whether a first round of treatment has already failed.
Amoxicillin: The Standard First Choice
For acute middle ear infections (the kind that causes deep ear pain, especially in children), amoxicillin at a high dose is the go-to treatment. Doctors typically prescribe it twice a day. The three bacteria most commonly responsible for middle ear infections are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, and amoxicillin covers all three reasonably well.
How long you take it matters. Children under two usually need a full 10-day course, while kids aged two to five can often finish in seven days. Children over five and adults with uncomplicated infections typically take it for just five days. Your doctor may prescribe a longer course if the eardrum has ruptured or the infection keeps coming back.
When Amoxicillin Doesn’t Work
If symptoms haven’t improved after 48 to 72 hours on amoxicillin, the infection may involve bacteria that produce enzymes capable of breaking down the drug. The standard next step is amoxicillin-clavulanate, a combination that pairs amoxicillin with an ingredient that blocks those enzymes. A high-ratio formulation (14 parts amoxicillin to 1 part clavulanate) was developed specifically for resistant ear infections, keeping the amoxicillin dose high enough to fight tougher strains of pneumococcus while also covering the enzyme-producing bacteria.
Resistance is a real consideration. Roughly two in five pneumococcal infections now involve bacteria that are no longer fully susceptible to at least one antibiotic, according to CDC surveillance data. That’s why dosing matters: higher doses of amoxicillin can still overcome many partially resistant strains, which is the reason doctors prescribe it at the upper end of the dosing range rather than at lower, older doses.
Options if You’re Allergic to Penicillin
If you’ve had a mild or moderate reaction to penicillin (a rash, for example, but not throat swelling or anaphylaxis), certain cephalosporin antibiotics are safe alternatives. The cross-reaction rate between penicillin and cephalosporins is about 0.1% in people with non-severe penicillin allergies. The most commonly recommended options include cefdinir, cefuroxime, cefpodoxime, and ceftriaxone (which is given as an injection rather than taken by mouth).
For people with a history of severe penicillin allergy, the choices narrow. Azithromycin and clarithromycin are sometimes used, but they have limited effectiveness against the bacteria that cause most ear infections. Many strains of Haemophilus influenzae and Streptococcus pneumoniae are resistant to these drugs, so they’re reserved for situations where nothing else is tolerated. Azithromycin in particular is generally not recommended for middle ear infections when other options are available.
Ear Drops for Outer Ear Infections
Outer ear infections, often called swimmer’s ear, are a completely different situation. These infections affect the ear canal rather than the space behind the eardrum, and they’re treated with antibiotic ear drops instead of oral antibiotics. A common prescription is ciprofloxacin combined with dexamethasone (a steroid that reduces swelling and pain). You place the drops into the affected ear twice a day, morning and evening, for seven days.
Oral antibiotics are rarely needed for swimmer’s ear unless the infection has spread beyond the ear canal. The drops deliver a high concentration of antibiotic directly to the infection site, which makes them more effective for this type of infection and avoids the digestive side effects that come with pills or liquid antibiotics.
Side Effects to Expect
Diarrhea is the most common side effect of oral antibiotics used for ear infections, but the rate varies significantly depending on which drug you take. A systematic review of clinical trials found that high-dose amoxicillin-clavulanate caused diarrhea in about 19% of children, the highest rate among commonly prescribed options. High-dose amoxicillin alone came in at roughly 14%, cefdinir at 13%, and lower-dose amoxicillin at about 9%. Azithromycin had the lowest rate at around 2%, but as noted, it’s less effective against the bacteria involved.
For children in diapers, antibiotic-related diarrhea often leads to diaper rash. Probiotics taken alongside antibiotics may help reduce loose stools, though the evidence is mixed. The side effects resolve once the antibiotic course is finished.
Not Every Ear Infection Needs Antibiotics
Many ear infections, particularly in children over two with mild symptoms, clear up on their own within a few days. A “watchful waiting” approach, where you manage pain with over-the-counter pain relievers and only start antibiotics if symptoms worsen or don’t improve within 48 to 72 hours, is a well-established strategy. Pain control is recommended for all patients regardless of whether antibiotics are prescribed, since antibiotics treat the infection but don’t relieve pain quickly.
Watchful waiting is less appropriate for children under two, kids with severe symptoms (high fever, significant ear pain, or infection in both ears), and anyone with a ruptured eardrum. In those cases, starting antibiotics right away is the standard approach.