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Why Tooth Pain Got Worse After Starting Antibiotics

If your tooth pain is worse after starting antibiotics, you may not have given it enough time to work or it could be a developing complication. The former is good news while the latter is bad news.

amoxicillin antibiotic

However, before you go assuming the worst you should rule out if you've waited long enough for the antibiotics to take effect.

Table of Contents:

Antibiotics need time to work

Antibiotics do not work immediately because it requires time to build up to a sufficient concentration in the blood to take effect. Prior to that point, it isn't enough to begin fighting the infection and reducing your tooth pain.

Other factor to take into consideration: Different types of antibiotics have different working times. On average, it may take about 1-2 hours before it starts working but it won't be for another 24-48 hours before you notice the effect.

Below is a table showing the four most commonly prescribe antibiotics for dental uses and the time it takes for them to work.


Tmax (Time to reach peak concentration)





In summary, the oral antibiotics won't be effective until at least 1-2 hours after taking them. After that, you may not notice any pain alleviation until approximately 24-48 hours afterwards.

Therefore, you should wait at least 24-48 hours after taking your antibiotics before you even consider that you may have a potential complication.

Why toothache got worse after antibiotics

If it has been at least 24-48 hours since you've began taking antibiotics and the pain is getting worse, here are some reasons as to why.

Potential reasons for worsening pain:

  • Antibiotics are not an analgesic which means they don't directly relieve toothaches.

  • Perhaps you took the medication too late and the infection is too severe to be treated with pills alone.

  • You may have developed a dental complication.

Not an analgesic

If you're taking antibiotics and nothing else, we're not surprised that your tooth pain isn't getting better. After all, antibiotics are an antibacterial medication and they are NOT painkillers.

In other words, that bottle of amoxicillin you got from your dentist has zero pain alleviating effect because it is NOT a pain reliever! Typically that is why dentists always prescribe a pain medication in conjunction with the amoxicillin. Taking antibiotics alone will not relieve your toothache.

amoxicillin and ibuprofen

Therefore, we highly recommend taking pain medication (ibuprofen/acetaminophen) in conjunction with the antibiotics to ensure pain alleviation.

Took it too late

If you've developed a dental abscess and it is starting to swell up, antibiotics will only reduce the swelling if you take it within 48 hours.

If you start taking the pills 48 hours after the abscess started, it may be too late. What will happen is that the swelling will not come down in size because the infection is too large to be treated with systemic medication alone.

Key points:

  • Antibiotics only work if taken within 48 hours of the infection starting.

  • Taking it after 48 hours will have no effect.


Your tooth pain may be getting worse because the infection could have spread to the point where antibiotics no longer have any effect.

Infected dental conditions which are immune to antibiotic therapy:

  • Infected tooth nerve. Once the tooth nerve succumbs to bacteria and it dies, taking antibacterial pills will do nothing. You will need the dead tooth nerve physically removed from the tooth.

  • Periapical abscess. An abscess that is developing at the tip of the root tip cannot be reached by systemic medication. These need to be mechanically treated.

  • Facial swelling lasting more than 2 days. Swelling that persists for longer than 2 days are too severe to be treated with just pills. These require an incision into the abscess and then completely drained.

  • Fractured tooth. If the pain is a result of a cracked tooth, it will need to be repaired or extracted. There is no other way to fix a severe crack.

If you've any of the above conditions, they are essentially beyond systemic antibacterial help. You will need to see a dentist for professional treatment.

What to do

The first thing you need to do if you notice the tooth pain getting worse despite starting antibiotics is to give it at least 24 hours. You want to make sure the medication has had time to take effect first.

However, if your condition remains unchanged after that time or it is getting progressively worse, you should return to your dentist to explore other treatment options.

Additional treatment

Perhaps taking antibacterial medication alone was insufficient to treat your condition. You may need additional dental treatment in order to get rid of the toothache.

Potential palliative dental treatment:

  • Incision and drainage. This procedure is commonly known as draining an abscess. A cut will be made into the swollen area and the pus will be physically drained from it.

  • Root canal. An infected nerve or an abscess inside of the tooth can only be eliminated by cleaning out the inside of the canals. This process removes the nerve and all of the infection within it. Afterwards the tooth will be dead.

  • Tooth extraction. If the abscess is too severe, the tooth may not be restorable. The only option left would be to extract the entire tooth.

Typically if you receive one of the above treatments the pain should go away immediately.

When will it get better?

Unfortunately if the antibiotics aren't working and the tooth pain is getting worse, it won't get better without additional treatment. The only way to permanently get rid of the pain is by seeing a dentist.

Essentially, pain due to infections will last forever unless it is treated by a dentist. The reason is because pain alleviating remedies only relieve the pain temporarily but do nothing to treat the source of it.



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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