Most amoxicillin prescriptions last between 5 and 10 days, depending on the type of infection being treated. A strep throat course runs 10 days, while an ear infection in an older child might only need 5. Your specific prescription length is based on the infection site, your age, and how complicated the infection is.
Course Length by Infection Type
The number of days varies quite a bit depending on what’s being treated. Here are the most common infections and their typical amoxicillin durations:
- Strep throat: 10 days. This is one of the longer courses because undertreating strep can lead to complications like rheumatic fever. The full 10 days applies to both children and adults.
- Ear infections: 5 to 10 days. Children under 2 generally need the full 10 days. Kids 2 and older with a straightforward ear infection typically do well with just 5 days. The longer course is also used for recurring ear infections or cases where the eardrum has ruptured.
- Sinus infections: 7 days is standard for acute bacterial sinusitis in adults.
- Pneumonia: 5 days minimum. Current guidelines from the American Thoracic Society and Infectious Diseases Society of America recommend at least 5 days for community-acquired pneumonia, with a reassessment afterward to confirm the patient is improving.
- Urinary tract infections: 3 days for uncomplicated UTIs in non-pregnant women, 7 days for men and pregnant women. (Amoxicillin isn’t always the first choice for UTIs, but when it’s used, these are the typical lengths.)
- Skin infections: 5 to 7 days for uncomplicated cases, sometimes extended to 10 days if the infection is slow to clear.
- Dental infections: 3 to 7 days, tailored to the severity. A simple dental abscess might clear in a shorter course, while more complicated infections need the full week.
Why Some Courses Are Longer Than Others
The duration isn’t arbitrary. It reflects how long the bacteria in a given location typically take to be killed off, and what happens if they aren’t. Strep throat gets a 10-day course not because the bacteria are especially hard to kill, but because incomplete treatment raises the risk of serious inflammatory complications. Pneumonia, on the other hand, responds well to shorter courses in most patients. A large study of over 55,000 hospitalized pneumonia patients found that clinically stable patients who received 3 to 4 days of antibiotics had similar outcomes to those who received 5 or more days, with no meaningful difference in mortality, readmission, or secondary infections.
That said, shorter courses worked only for a narrow group. About 90% of patients in that study were excluded because of underlying health conditions, more severe illness, or unstable vital signs. For higher-risk patients, the standard or longer course remains important.
The Shift Toward Shorter Courses
For decades, the standard advice was that longer antibiotic courses are always safer. That thinking has started to shift. Growing evidence shows that for several common infections, shorter courses work just as well as longer ones, with fewer side effects like diarrhea and fewer opportunities for bacteria to develop resistance. The World Health Organization acknowledges that shorter courses may be equally effective for some infections.
This doesn’t mean you should shorten your own prescription. It means your doctor may prescribe a 5-day course where a 10-day course used to be routine, and that’s based on current evidence, not a shortcut.
What Happens If You Stop Early
Feeling better after a few days is common, but it doesn’t always mean the infection is fully cleared. Remaining bacteria can regrow if treatment stops too soon, potentially causing a relapse that’s harder to treat the second time around. The WHO is clear on this point: symptom improvement is not the same as infection resolution.
If you’re experiencing side effects that make you want to stop, contact whoever prescribed the antibiotic. They can assess whether switching medications makes more sense than stopping treatment altogether.
What to Do If You Miss a Dose
Take the missed dose as soon as you remember. If it’s almost time for your next scheduled dose, skip the missed one and continue your regular schedule. Don’t double up to compensate. Taking two doses at once increases the risk of side effects like nausea and diarrhea without making the antibiotic work faster.
Missing a single dose occasionally won’t derail your treatment, but consistently skipping doses reduces the drug’s effectiveness. If you have trouble remembering, setting a phone alarm for each dose can help you stay on track through the full course.