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Amoxicillin For Dental Infections: Dosages & Indications

Amoxicillin is the most commonly prescribed dental antibiotic that is used to treat dental abscesses and infections.


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


Indications

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.


Indications:

  • Tooth infection with swelling

  • Wisdom teeth pain with swelling

  • Dental abscess with facial swelling

  • Severe generalized gum swelling


Contraindications:

  • Tooth infection with no swelling

  • Wisdom teeth pain with no swelling

  • Dental abscess with no facial swelling

  • Gum swelling around one tooth


Some common misconceptions for when you would take antibiotics is after a root canal or tooth extraction, including 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.


Dosages

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.


Antibiotic

Dosage

Frequency

Amoxicillin

500 mg

Every 8 hours (q8h)

Amoxicillin and Clavulanate Acid

875 mg + 125 mg

Every 12 hours (q12h)

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.


Antibiotic

Time to Peak Plasma Levels

Half life

1-2 hours

61.3 mins

1.5 hours

1-1.3 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:

  • 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


Rare side effect: Potential tooth staining but only with liquid formulations.


Antibiotic resistance

Often overlooked but taking excessive amounts of antibiotics can lead to bacteria that acquire antibiotic resistance. These strains of bacteria become immune to antibiotics so taking more will have no effect on them.


This is a major problem because management for these types of bacteria require hospitalization. It may be out of your dentist's hands at this point.


Safety

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.


Recommendations

Dosage

Absolute maximum dose

4000 mg/day

Recommended maximum dose

80-90 mg/kg/day

Symptoms of overdose:

  • 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.

David Chen 200 x 200.jpg

About the author: Dr David Chen, DDS

Hello, I'm Dr Chen and I'm an actively practicing dentist in Long Island City, NY. I graduated from Columbia University College of Dental Medicine in 2016 but prior to going to dental school I was already working in the dental field. It's been more than a decade since I first got to know dentistry and let me tell you, time flies by quickly. Since then I've developed a fondness for writing, which is how this all got started!

Association Memberships:

Medical Disclaimer:

This blog is purely meant for information purposes and should not be used as medical advice. Each situation in your mouth is unique and complex. It is not possible to give advice nor diagnose any oral conditions based on text nor virtual consultations. The best thing to do is to go in person to see your dentist for an examination and consultation so that you can receive the best care possible.

The purpose of all of this oral health information is to encourage you to see your dentist and to inform you of what you may expect during your visit. Due to the unfortunate nature of dentistry, there isn't really any true home remedies that will get rid of dental problems. Roughly 99.99% of them require in-person intervention by a healthcare professional.

Hint: That is the reason why you can't eliminate seeing dentists in your life!

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