There are several antibiotics that kill the common mouth bacteria that cause tooth infections. The best (first-line) antibiotics for tooth infection include:

• amoxicillin
• penicillin
• cephalexin
• clindamycin
• azithromycin

The best antibiotics for tooth infection are known to fight the bacteria most commonly found in your mouth. When your dentist prescribes one of these antibiotics, the choice will depend on whether you are allergic to penicillin or have other issues.

Amoxicillin is often the first choice because it is widely effective and has the fewest gastrointestinal side effects.

The American Dental Association (ADA) recommends:

• Oral amoxicillin (if you are not allergic to penicillin): 500 mg three times a day for 3 to 7 days.
• Oral penicillin (as a second option): 500 mg four times per day for 3 to 7 days.

If you have a history of severe allergy (symptoms of hives, swelling or a drop in blood pressure) to penicillin, ampicillin, or amoxicillin, the ADA recommends:

• Oral azithromycin: loading dose 500 mg on day 1, followed by 250 mg for an additional 4 days; or
• Oral clindamycin: 300 mg four times a day for 3 to 7 days.

If you have a history of mild allergy to penicillin, ampicillin or amoxicillin, the ADA recommends:

• Oral cephalexin: 500 mg four times a day for 3 to 7 days.

Other antibiotics may be used if first-line antibiotics are not working. They include amoxicillin with clavulanate (Augmentin) or metronidazole.

Antibiotics for tooth abscess complication

A deep neck infection is a dangerous complication of tooth infection when it spreads into the space between neck muscles. An abscess forms inside the neck. The abscess may swell and block breathing or swallowing.

Deep neck infections are treated in the hospital with an intravenous (IV) antibiotic along with opening the space in the neck to drain the abscess. For this type of infection, the best antibiotic may be amoxicillin with clavulanate through an IV.

The antibiotic for a deep neck infection may change if a lab culture shows that bacteria are more sensitive to another antibiotic (called a culture and sensitivity).

Taking antibiotics

If you need an antibiotic to treat your tooth infection, taking the full course exactly as directed by your doctor will help to eradicate the infection. Not doing so can make a recurring infection harder to treat.

Antibiotics may have side effects such as:

• Rash (a sign of an antibiotic allergy)
• Nausea
• Yeast infection
• Diarrhea

Severe diarrhea may be a sign of an infection in the gut called C. diff. This infection occurs when normal bacteria in your gut are killed by antibiotics and C. diff bacteria take over. C. diff is a serious infection that needs prompt treatment.

Antibiotic resistance

Sometimes the antibiotics used to treat infection don’t work well. This may be due to antibiotic resistance. This happens when the bacteria in your tooth infection aren’t killed by the antibiotic drug. Overuse of antibiotics in people over time can cause this to happen. In this case, you may have to switch to a different antibiotic.

Many tooth infections can be treated with dental care alone. Using antibiotics only when needed reduces the risk of bacteria developing antibiotic resistance.

If you have pain only and without swelling, your dentist may be able to treat your tooth with a dental procedure without the use of antibiotics. This may include removing the tissue inside your tooth (pulpectomy) or doing a root canal. If you have symptoms such as pain, swelling and fever, antibiotics may be part of your treatment along with a dental procedure.

Tooth infection prevention

The best way to avoid a tooth infection is to see your dentist regularly and maintain good oral hygiene with brushing and flossing. A dentist can help treat tooth issues that can lead to infection or pain that may become more severe such as:

• A cracked tooth
• Mouth or tooth pain with swelling or fever

Trouble with swallowing or breathing requires medical attention right away.