What antibiotic is good for tooth infection? A Guide to Treatment Options

October 12, 2025 •

4 min read

According to the American Dental Association (ADA) and CDC guidelines, not all dental pain requires antibiotics, but for infections with systemic symptoms like fever and swelling, a prescription is necessary. A dental professional will determine what antibiotic is good for a tooth infection based on your specific condition and medical history.

Quick Summary

For a tooth infection, a dentist may prescribe amoxicillin or penicillin V as the first-line treatment, with alternatives available for those with penicillin allergies. Definitive dental procedures, not antibiotics alone, are needed to cure the underlying issue.

Key Points

Amoxicillin as First Choice: In patients without a penicillin allergy, amoxicillin is the most commonly prescribed first-line antibiotic for tooth infections.
Alternatives for Penicillin Allergy: For patients with severe penicillin allergies, clindamycin or azithromycin are common alternatives. Cephalexin may be considered for milder allergies.
Antibiotics Alone Are Not Enough: Antibiotics will not permanently cure a dental infection. They are used to control the spread of infection, but a definitive dental procedure (e.g., root canal or extraction) is required to remove the source.
Complete the Full Course: Even if symptoms improve quickly, it is crucial to finish the entire course of antibiotics as prescribed to prevent the infection from returning and to avoid antibiotic resistance.
Beware of Drug Interactions: If prescribed metronidazole, you must completely avoid alcohol during treatment and for at least 48 hours after completion to prevent a severe reaction.
Caution with Clindamycin: Clindamycin carries a higher risk of causing Clostridioides difficile (C. diff) infection, a severe and potentially fatal form of colitis, compared to other antibiotics.

The Role of Antibiotics in Dental Infections

A tooth infection, also known as a dental abscess, occurs when bacteria invade the tooth's inner pulp and spread to the surrounding tissues. While over-the-counter pain medication can alleviate discomfort, antibiotics are necessary to combat a spreading bacterial infection and are not always the first step. In many cases, if an infection is localized, your dentist will perform a definitive procedure, such as a root canal or extraction, to treat the problem without antibiotics. Antibiotics are typically reserved for infections that have spread beyond the initial area and are causing systemic symptoms like fever, fatigue, or swelling.

First-Line Antibiotics for Tooth Infections

When antibiotic therapy is required, dentists often start with a narrow-spectrum medication that is effective against common oral bacteria. The choice of antibiotic can vary based on the specific type of infection and the patient's medical history.

Amoxicillin

Amoxicillin is a penicillin-type antibiotic that is frequently prescribed for tooth infections. It works by inhibiting the synthesis of the bacterial cell wall, which prevents bacterial growth and reproduction. It is a popular choice for several reasons:

Effectiveness: It is effective against a wide range of bacteria commonly found in oral infections.
Convenient Dosing: It can have a simpler dosing schedule compared to penicillin V.
Combats Resistance: A combination of amoxicillin and clavulanic acid (Augmentin) is a stronger option used for more severe infections or against resistant bacteria.

Penicillin V

Penicillin V (or phenoxymethylpenicillin) has traditionally been a primary choice for dental abscesses. It is also highly effective against odontogenic (dental-origin) infections. However, the rise of penicillin-resistant bacteria has led some practitioners to favor amoxicillin or other options.

Amoxicillin/Clavulanate (Augmentin)

This combination broadens the antibiotic's effectiveness. Clavulanate is a beta-lactamase inhibitor, meaning it protects the amoxicillin from being broken down by certain enzymes that resistant bacteria produce. It is used for more serious infections or when standard amoxicillin fails.

Alternative Antibiotics for Tooth Infections

For various reasons, including penicillin allergies, dentists have alternative antibiotic options. The American Dental Association (ADA) provides guidance on prescribing alternatives based on the patient's allergy history.

Options for Penicillin-Allergic Patients

Clindamycin: A potent option for those with severe penicillin allergies, clindamycin is effective against many odontogenic pathogens. However, it is also associated with a higher risk of Clostridioides difficile (C. diff) infection, a serious intestinal condition, so its use is carefully considered.
Azithromycin: This antibiotic is a macrolide that can be a suitable alternative for mild to moderate infections in penicillin-allergic patients. It often has a simpler, once-a-day dosing schedule.
Cephalexin: For patients with a mild penicillin allergy (not involving anaphylaxis, angioedema, or hives), cephalexin may be an alternative. It belongs to the cephalosporin class, which has a similar structure to penicillin, so there is a small risk of cross-reactivity.

Metronidazole

This antibiotic is highly effective against anaerobic bacteria, which are common culprits in tooth infections, and is often prescribed in combination with a penicillin antibiotic for broader coverage. It is important to avoid alcohol while taking metronidazole due to potential side effects like nausea and vomiting.

Table: Comparison of Common Antibiotics for Tooth Infections


Antibiotic	Class	Common Use	Consideration	Potential Side Effects
Amoxicillin	Penicillin	First-line choice for most infections.	Not suitable for patients with penicillin allergies.	Nausea, diarrhea, allergic reaction.
Penicillin V	Penicillin	Traditional first-line therapy.	Higher resistance than amoxicillin; not for penicillin-allergic patients.	Nausea, diarrhea, allergic reaction.
Amoxicillin/Clavulanate	Penicillin	Used for severe infections or resistant bacteria.	Risk of C. diff and hepatotoxicity.	Diarrhea, nausea, increased risk of C. diff.
Clindamycin	Lincosamide	Alternative for penicillin-allergic patients.	Higher risk of C. diff infection.	Diarrhea, nausea, severe colitis.
Azithromycin	Macrolide	Alternative for penicillin-allergic patients (mild-moderate infections).	Increasing resistance rates.	Nausea, abdominal pain, diarrhea.
Metronidazole	Nitroimidazole	Often combined with penicillin for broader coverage.	Avoid alcohol completely while taking and for 48 hours after stopping.	Nausea, metallic taste, headache.

What to Expect from Antibiotic Treatment

After starting antibiotics, you may feel some relief from pain and swelling within 24 to 72 hours, but it is crucial to complete the entire course as prescribed. Stopping early, even if you feel better, can lead to the infection returning and may contribute to antibiotic resistance. A typical course of antibiotics for a dental infection lasts between 3 and 10 days, depending on the specific drug and severity.

The Importance of Definitive Dental Treatment

It is essential to understand that antibiotics alone will not cure a tooth infection. They can help manage the infection and prevent its spread, but they do not address the root cause, such as a deep cavity or cracked tooth. The infection is contained within the tooth's pulp, which has a poor blood supply, limiting the antibiotic's effectiveness. Therefore, definitive dental treatment, such as a root canal or extraction, is required to remove the infected pulp and resolve the issue completely. Your dentist will determine the appropriate procedure once the acute infection is under control.

Conclusion

Selecting what antibiotic is good for a tooth infection is a decision made by a dental professional based on the severity of the infection, bacterial susceptibility, and patient factors like allergies. While amoxicillin and penicillin V are common first choices, several effective alternatives exist for those with penicillin allergies, such as clindamycin or azithromycin. Regardless of the medication prescribed, antibiotics are only a temporary measure. To prevent the infection from returning and spreading, definitive dental treatment is a necessary follow-up to address the underlying cause.

For more detailed information on dental infection management, consult the American Dental Association guidelines.

Frequently Asked Questions

Antibiotics are typically needed if the tooth infection has spread and is causing systemic symptoms, such as fever, fatigue, or swelling that extends to the jaw or neck. For a localized abscess, your dentist may prefer to perform a dental procedure first.

You may start to feel some relief within 24 to 72 hours of starting antibiotics, but it is important to complete the entire course, which typically lasts between 3 and 10 days, for full effectiveness.

No. Antibiotics help kill the bacteria and control the spread of the infection, but they do not address the underlying cause within the tooth's pulp. The infection will likely return without definitive dental treatment like a root canal or tooth extraction.

For patients with a severe penicillin allergy, clindamycin is often prescribed. Other alternatives include azithromycin for mild to moderate infections. For non-severe allergies, cephalexin might be considered.

Augmentin is a stronger version of amoxicillin and is effective against a broader range of bacteria, including resistant strains. It is used for more severe infections or when standard amoxicillin is not sufficient.

If you are prescribed metronidazole, you must avoid alcohol completely during treatment and for at least 48 hours afterward. Combining them can lead to a severe reaction with symptoms like nausea and vomiting.

Stopping your antibiotic course early, even if your symptoms have improved, can allow some bacteria to survive and become resistant. This can cause the infection to return and make it harder to treat in the future.