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How long does amoxicillin take to work for tooth infections?

If your dentist prescribes this antibiotic, the infection should start to clear up within the first few days of taking it
Rosemary Black
By | Dec. 27, 2024 Medically reviewed by Catherine Chien, DDS
A prescription pad and bottle of pills: How long does amoxicillin take to work for tooth infections?

Key takeaways

  • Amoxicillin is often the first-line antibiotic for a tooth infection in people who are not allergic to penicillin.

  • Amoxicillin does not work immediately, but you should begin to notice relief within 24–72 hours of starting it.

  • An antibiotic by itself typically won’t cure a tooth infection. Dental treatment may be necessary to address the cause of the infection and prevent the infection from spreading or returning.

  • Your dentist may ask you to wait for symptoms to clear up on their own before taking an antibiotic for a tooth infection.

In this article:

If you have a toothache along with some swelling and sensitivity in the area, you may have a tooth infection or even a tooth abscess—a pus-filled pocket caused by a bacterial infection in the teeth or gums. In addition to treating the cause of the infection, such as performing a root canal to clear the infection or extracting the infected tooth, your dentist may prescribe amoxicillin, an antibiotic that kills certain kinds of harmful bacteria and keeps them from growing. Dental infections can be painful without treatment, and most people want to know how long it takes their antibiotic to work and when to expect the pain to go away. 

How long does amoxicillin take to work for tooth infections?

Some people start to feel better on the first day of taking an antibiotic. For others, it takes a bit longer. “You should begin to notice pain relief within 24–72 hours after starting amoxicillin,” says Sean Ormond, MD, of Atlas Pain Specialists in Phoenix. “But antibiotics don’t provide immediate relief,” he says. “It takes time for the medication to reduce the bacterial load and for the inflammation in the mouth to decrease.” 

Although you may still have discomfort for the first couple of days after starting amoxicillin, this should gradually improve as the infection clears up. Your dentist may recommend medication to relieve discomfort while you wait for the amoxicillin to do its job.

When a dentist may prescribe amoxicillin for a tooth infection

“Infections in the mouth often occur because of tooth decay, gum disease, or trauma to the tooth,” Dr. Ormond says. “Amoxicillin can help by targeting and eliminating the bacteria, which allows the body to heal.” He says it’s those bacteria that cause inflammation when they get into the tooth’s pulp or root. 

American Dental Association (ADA) guidelines recommend antibiotics for dental infections in patients who have a fever and malaise—a feeling of discomfort or being unwell. “Tooth infections, especially those caused by bacterial growth in or around a tooth, can lead to swelling, pressure, and pain,” Dr. Ormond says. “The primary goal when a dentist prescribes amoxicillin for a tooth infection is to treat the underlying infection rather than directly relieve the pain.”

Swelling that doesn’t go away may be another reason for an antibiotic. “If there is swelling, a dentist may prescribe an antibiotic to minimize the risk of the infection, reduce the swelling, and reduce the pressure that is felt with the infection,” says Reshma Dhake, DDS, of Forever Dental in Chicago, Illinois. If swelling is severe, it is advised to seek help from a professional immediately.

But your dentist may not automatically tell you to take an antibiotic. “An antibiotic is not always prescribed for dental pain,” says Joshua David Segal, DDS, MD, MS, chair of the dental department at Staten Island University Hospital. “The ideal treatment for dental pain caused by a dental infection is to treat the source of the infection through some kind of dental intervention. An antibiotic may be an adjunct to this treatment, and amoxicillin may be the antibiotic that is prescribed.”

Antibiotics can be lifesaving, but they also need to be used with caution. In some cases, bacteria become able to defeat the very antibiotics that are meant to kill them. In these cases, the germs continue to grow. This is called antibiotic resistance, and when it occurs, the infections can be difficult or impossible to treat. When someone develops an antibiotic-resistant infection, the person may require costly alternative treatments, along with extended hospital stays. For those reasons, your dentist may recommend you wait a specific number of days to see if your symptoms improve before you fill your prescription. This is called delayed prescribing.     

Benefits of amoxicillin for tooth infections

Amoxicillin and penicillin are first-line treatments for tooth infections in situations when an antibiotic is recommended, and the person is not allergic to penicillin, according to the Journal of the American Dental Association (JADA). Amoxicillin is preferred over penicillin, however, because of its effectiveness against certain harmful bacteria and its lower rate of gastrointestinal side effects.

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“Amoxicillin works by attacking the protective outer layer (cell wall) of bacteria,” explains Alyssa M. Wozniak, Pharm.D., BCPS, assistant dean for clinical affairs, outreach, and special projects in the School of Pharmacy at D’Youville University in Buffalo, New York. “It stops the bacteria from building this wall, which they need to survive,” she says. “Without a strong wall, the bacteria break down and die, allowing your body to get rid of the infection.” 

Amoxicillin dosage for a tooth infection

JADA recommends 500 milligrams (mg) of amoxicillin three times a day for three to seven days for tooth infections. Ultimately, however, the dosage is based on the type and severity of the infection that’s being treated. It also varies by age, as amoxicillin doses for children are based on body weight, infection severity, and the degree of bacterial resistance.

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Be sure to take the amoxicillin as it was prescribed, take it on time, and finish all of it. Even when you notice an improvement in your symptoms, that doesn’t mean the infection is completely cleared. “If you don’t finish the amoxicillin or you skip doses, you run the risk of the infection returning or even of having it develop into an antibiotic-resistant infection,” Dr. Dhake says. She says you will likely need some dental work along with the antibiotic since you need to address the cause of the infection and prevent it from returning or spreading.

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What can you take with amoxicillin for tooth pain?

According to JADA, nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen (specifically, 400–600 mg ibuprofen plus 1,000 mg acetaminophen) may be effective in managing dental pain. It is generally safe for most people to take ibuprofen with amoxicillin. You may find that after a few days of taking the antibiotic, you will no longer need the ibuprofen or acetaminophen.

Amoxicillin side effects to be aware of

Amoxicillin is generally well-tolerated. “But as with any medication, there are side effects and allergic reactions that a person should be aware of,” Dr. Segal says. 

The most common amoxicillin side effects are an upset stomach, diarrhea, nausea, and vomiting. While taking amoxicillin, some people may develop a yeast infection. This can happen because antibiotics can disrupt the normal balance of bacteria in the body. Taking a probiotic during the course of antibiotics may be helpful.

If you’ve had a serious allergic reaction like severe swelling and trouble breathing to amoxicillin or similar antibiotics (like penicillin) in the past, avoid amoxicillin. “Be sure to tell your healthcare provider about any past severe reactions to antibiotics so they can find a safer option for you,” Dr. Wozniak says. There are safe and effective alternatives, such as clindamycin, for those allergic to amoxicillin.

What to do if amoxicillin doesn’t work for a dental infection

If your symptoms don’t improve after you finish your amoxicillin, call your dentist, who will reassess your condition. You may need additional tests or a different treatment. Your dentist may recommend another antibiotic, such as oral metronidazole, if amoxicillin fails to treat the infection. The dose of oral metronidazole would typically be 500 mg, three times a day for seven days.

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