Antibiotics for Tooth Infections: Fix the Tooth First
A bad tooth can hurt a lot. It is easy to just hand the patient some pills. But pills do not fix the tooth. The germs live inside the tooth, and medicine cannot reach them well there.
Fix the source
The real fix is to clean out the problem. That means a root canal, draining the pus, or pulling the tooth. Once the source is gone, most patients get better without any antibiotics at all.
When pills do help
Give antibiotics only when:
- The infection is spreading, like swelling that keeps growing.
- The patient feels sick, with a fever or trouble opening their mouth.
- You cannot fix the tooth right away, and there is pus or swelling.
A toothache with no swelling and no fever does not need antibiotics, even if treatment has to wait. Pain pills like ibuprofen with acetaminophen work better for that.
Which pill to pick
- Most adults: amoxicillin, 500 mg three times a day.
- Mild penicillin allergy (no hives or swelling): cephalexin, 500 mg four times a day.
- Serious penicillin allergy: azithromycin is a good choice. Clindamycin is a backup, since it can upset the gut badly.
Keep it short
Three to seven days is usually plenty. Check on the patient in about three days. They can stop the pills a day after they feel better. If they are not getting better, ask yourself if the tooth was really fixed before you add a stronger drug.
Send them to the ER
Some infections are an emergency. Send the patient to the ER right away if they have trouble breathing or swallowing, swelling under the tongue, or swelling that reaches the neck or near the eye. Pills alone will not keep them safe.
Where we learned this
- ADA guideline on antibiotics for dental pain and swelling (JADA, 2019)
- ADA chairside guide
- AAE guidance on antibiotics in endodontics (2017)
An educational summary for dental professionals. It is not a substitute for clinical judgment, the full guidelines, or an individual patient’s medical history and allergies.