Amoxicillin For Tooth Infection: Dosages & Indications

Written, Edited, and Reviewed by Dr David Chen.

Yes, amoxicillin does work for tooth infections. In fact, it is the most commonly prescribed dental antibiotic since it can be used to treat most infectious oral conditions, which include dental abscesses and infections.

Antibiotic Amoxicillin

With that being said, it is not a panacea because there are situations where it may be ineffective if used inappropriately. In order for amoxicillin to work effectively, you need to know when to use it and how much of it to take.

Amoxicillin overview:

  • Type of antibiotic: Penicillin (beta-lactam antibiotic).
  • Indications: Oral bacterial infections with swelling.
  • Contraindications: Mouth infections or toothaches without swelling.
  • Typical dosages: 500 mg every 8 hours (3 times a day) for 7 days.
  • Mechanism of action: Bactericidal via inhibition of cell wall synthesis by binding to penicillin-binding proteins thus inhibiting transpeptidation; Ultimately leads to activation of autolytic enzymes.
  • Side effects: Allergy, diarrhea, nausea, rash, urticaria, superinfection, candidiasis, fever, vomiting, erythema, dermatitis, angioedema, pseudomembranous colitis.
  • Safety: Anaphylaxis from allergic reaction; acute kidney failure

We will explore in further detail, the nitty gritty about each aspect of this antibiotic.


The most common situation to be prescribed amoxicillin at the dentist is if you have a tooth infection with swelling. Taking antibiotics is one of the treatment methods for that condition.


  • Tooth infection with swelling
  • Wisdom teeth pain with swelling
  • Dental abscess with facial swelling
  • Severe generalized gum swelling


  • Tooth infection with no swelling
  • Wisdom teeth pain with no swelling
  • Dental abscess with no facial swelling
  • Gum swelling around one tooth

Common misconceptions about when you would receive antibiotics is after a root canal or tooth extraction, which includes wisdom teeth. For routine procedures, you don’t actually need it!

Does amoxicillin work for a tooth infection?

Taking amoxicillin for a tooth infection is the proper course of treatment but only if there is associated jaw or face swelling. The antibiotics will help clear out the abscess and help reduce the swelling.

However, if you’ve an infection but there is NO SWELLING, then taking the amoxicillin will do little for the tooth infection. Taking the medication will not improve your condition.

Nonetheless, you for both of the above scenarios you still need to see a dentist for definitive treatment. The amoxicillin is more of an adjunctive treatment in addition to dental treatment.

Still need to see a dentist

Taking amoxicillin for a swollen tooth infection will help clear out the surrounding pus and bacteria. However, what it won’t do is permanently get rid of the source of the infection.

Most of the abscesses originate from a dying tooth nerve which is the source of the infection. Unless you physically remove the source of the abscess with a root canal, it will keep producing more bacteria and pus.

It is an unending cycle to continually take antibiotics. You must seek a dentist to permanently get rid of this once and for all.


The most common amoxicillin dosage for a tooth infection is 500 mg every 8 hours for 7 days. The time interval isn’t quite that strict so sometimes you can just do three times in a day instead.

However for a very severe oral infection, taking amoxicillin alone may be insufficient. For these situations, taking amoxicillin WITH clavulanate acid will be more effective.

AntibioticDose UnitFrequency
Amoxicillin500 mgEvery 8 hours (q8h)
Amoxicillin and Clavulanate Acid875 mg + 125 mgEvery 12 hours (q12h)
Amoxicillin dosage regimen table

Essentially, how much amoxicillin you should take for a dental abscess would depend on its severity. The more severe your condition is, you may need to take a higher dosage.

You won’t know how bad your condition is, only your dentist will be able to determine that. Consequently that means how much antibiotics you should take will be decided by your dentist.

How do I get amoxicillin?

This antibiotic is available by prescription only, which means you need to see a dentist or physician to get it. You cannot purchase it over the counter at the pharmacy nor can you order it online.

Mechanism of action

Amoxicillin is a beta-lactam class of antimicrobials that is bactericidal. That means it is directly harmful to the bacteria and will kill them.

As with all beta-lactams, it interferes with bacteria cell wall synthesis by binding to penicillin-binding proteins which inhibit transpeptidation (the cross-linking process in cell wall synthesis).

This leads to the activation of autolytic enzymes in the bacterial cell wall, thus resulting in lysis of the cell wall. Ultimately the bacteria dies.

How long does amoxicillin take to work for a tooth infection?

On average, it takes about 1-2 hours after you take amoxicillin for it to start working for a tooth infection. That is the time it takes for the medication to reach peak blood levels.

AntibioticTime to Peak Plasma LevelsHalf life
Amoxicillin1-2 hours61.3 mins
Amoxicillin and Clavulanate Acid1.5 hours1-1.3 hours

About 60% of this antibiotic gets excreted in the urine after 6-8 hours.

What if the antibiotic doesn’t work?

If you’ve been taking antibiotics but you notice that your tooth abscess is still swollen and not decreasing in size, it means that it’s not working. In other words, the infection is too severe to treat with amoxicillin alone, you will need professional intervention by a dentist.

Most likely, the abscess will need to be drained and then the tooth treated with either a root canal or extraction.

  • Dental abscess drainage. An incision will be made into the swelling and then the purulence will be manually drained.
  • Root canal. Remove the infected nerve within the tooth.
  • Extraction. Remove the entire infected tooth from the jaw bone.

You must continue taking the antibiotics after the above procedures and finish the entire dose regimen. If you don’t, there is a chance the tooth infection can come back.

Side effects

Taking amoxicillin can result in some side effects. Some are simply mild and are an inconvenience while others are severe and require immediate medical attention.

Mild adverse effects that you should let your doctor know:

  • nausea
  • vomiting
  • diarrhea
  • changes in taste
  • headache

Severe side effects where you need medical help immediately:

  • rash
  • skin blisters or peeling
  • itching
  • hives
  • wheezing
  • difficulty swallowing or breathing
  • swelling of the face, throat, tongue, lips, and eyes
  • severe diarrhea that can be watery or bloody

Antibiotic resistance

Often overlooked but taking excessive amounts of antibiotics can lead to antibiotic resistant strains of bacteria. This is a major problem because management for these type of bacteria require hospitalization.


When taken as directed, amoxicillin is relatively safe as long as you are not allergic to it. However, as with all prescription medications, you can overdose on it if you take more than the recommended amount.

Absolute maximum dose4000 mg/day
Recommended maximum dose80-90 mg/kg/day
Dose limits for amoxicillin – Table

Overdose symptoms:

  • cloudy or bloody urine
  • decreased urination
  • swelling of any part of the body
  • confusion
  • nausea
  • vomiting

Expired amoxicillin

You should not use expired amoxicillin for a tooth infection because leftover antibiotics should be disposed of according to MedLinePlus.

  • Liquid suspension formulas need to be discarded after 14 days.
  • All formulations should never be stored in the bathroom. It needs to be in a cool dry place.

Therefore, if you have left over expired amoxicillin, you should not use it. Please dispose of them according to the FDA instructions.


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Our purpose at afterva, is to encourage you to seek in person care with a doctor. It's not meant to be a substitute for medical advice. Each situation is unique and that makes it impossible to diagnose and treat without a clinical exam.

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