The Guide For Antibiotics Before Dental Work

Written & Reviewed by Dr David Chen

Antibiotic prophylaxis (premedication) is required for dental procedures that induce bleeding if you’ve certain health conditions. If you need it, it is important to take it because there are medical consequences for not doing so.

We will explain how to do it as well as who, what, when, where, and why it is needed.

amoxicillin RX

Although before we start, I’d like to give you a personal recount of why this is important.

I had a patient email us asking for a prescription for antibiotic prophylaxis. I check his chart and see that he wasn’t allergic any medication so a RX for 2g of amoxicillin was sent to his pharmacy. He emails us back shortly afterwards, stating that 2g was not enough and that he needed 3g instead.


That is unusual, I had to email him back with links to the premedication guidelines as well as research studies, telling him why we prescribed 2g instead of 3g. If he needed more than what the guidelines indicated, he would need to ask his physician.

So, do you know what you’re supposed to take and how much of it?

Our purpose here today is to provide clarity for what is customarily meant to be done. All of the information provided will be based on the guidelines from the American Heart Association (AHA) and the American Dental Association (ADA).

How to premedicate for dental procedures

Antibiotics for prophylaxis should be orally taken 30-60 minutes prior to your dental procedure. Which one you take and how much of it will depend on if you’re allergic to penicillin or not. Whether you’re an adult or child will also affect it.

Amoxicillin2 g50 mg/kg
Azithromycin500 mg15 mg/kg
Cephalexin2 g50 mg/kg
Doxycycline100 mgif < 45 kg, then 2.2 mg/kg;
if > 45 kg, then 100mg
Clindamycin600 mg20 mg/kg
Antibiotic Prophylactic Regimens for Dental Procedures

How to premedicate:

  1. Take antibiotic 30-60 mins prior to dental appointment.
  2. Try to have a meal or snack with the medication to prevent upset stomach.
  3. Go to your appointment and inform your dentist, you’ve complied with protocol.

Penicillin allergy:

  • Do not take amoxicillin.
  • Take azithromycin or doxycycline instead.

Penicillin allergy WITH heart condition:

  • Do not take amoxicillin
  • Do not take clindamycin or azithromycin.
  • Take doxycycline instead.

Cephalexin can also be safely taken for those with a penicillin allergy. Initial studies quoted a 10% cross-allergy risk with penicillin but recent research found it to be much lower. A 2012 study in the Journal of Emergency Medicine found the number closer to 1%.

Due to the extremely low chance of an adverse reaction, it is considered a safe and valid alternative.

Clindamycin NOT recommended

In the past, dentists prescribed clindamycin as the antibiotic of choice for those with penicillin allergies. However, based on findings in a 2015 study done in the UK, there were far too many complications (some were even fatal) with using it.

Results from study:

  • Adverse drug reaction rate for amoxicillin was 0 fatal reactions per million RX.
  • Clindamycin had 13 fatal and 149 non-fatal reactions per million RX.
  • Most of the adverse drug reactions from clindamycin were Clostridium difficile infections.

Due to the overwhelming adverse reactions from using clindamycin as an antibiotic prophylaxis, it has now been removed from the 2021 guidelines by the AHA.

In other words, you’re NOT supposed to take clindamycin if you’re allergic to penicillin and you need dental work done. In lieu of it, the next best choice seems to be azithromycin.

We left clindamycin in the antibiotic prophylaxis chart above with a strike-through to let you know that it was once appropriate but is not anymore.


Azithromycin may be the preferred choice in lieu of clindamycin but studies have shown that it should be used with caution in those with heart conditions.

A study found that patients with a prolonged QTc interval of >450 milliseconds as detected by ECG are at risk of a serious cardiac event. The recommendation is to use doxycyline instead.

What if I forgot to take it?

If you forgot to take your antibiotics 30-60 minutes before your dental procedure, you can still take it immediately before treatment. Alternatively, the guidelines also state that you may still take it even up to two hours after your procedure.

What to do for missed dose:

  • Take it right before your dentist starts the procedure.
  • Or take it up to 2 hours after finishing your dental treatment.

You should still be safe if you do either of the two if you inadvertently forgot to take it!

Who should premedicate?

The AHA and ADA have identified four groups of medical conditions that may have a high risk for an adverse outcome, viridans group streptococcal (VGS) infective endocarditis (IE).

  • Group 1: Prosthetic cardiac valve or prosthetic material used for cardiac valve repair or other implantable cardiac devices (e.g. transcatheter aortic valve implantation)
  • Group 2: Previous, relapse, or recurrent IE
  • Group 3: Congenital heart disease (CHD)
  • Group 4: Cardiac transplant recipients

The AHA also has a convenient printable wallet card for patients on preventing IE.

Prosthetic cardiac valves and material

  • Presence of prosthetic cardiac valves
  • Transcatheter implantation of prosthetic valves
  • Homografts
  • Cardiac valve repair devices (annuloplasty rings, chords, clips)
  • Left ventricular assist devices or implantable heart

Previous, relapse, or recurrent IE

  • History of infective endocarditis

Congenital heart disease

Congenital meaning these conditions were present since birth.

  • Unrepaired cyanotic CHD (palliative shunts and conduits)
  • Completely repaired cyanotic heart defect (within first 6 months)
  • Repaired CHD with residual defects at the site or near prosthetic patch/device
  • Surgical or transcatheter pulmonary artery valve or conduit placement (Melody valve and Contegra conduit)

Cardiac transplant recipients

Risk for infective endocarditis is the highest during the first six months of transplant. Research data is limited but they’re typically immunosuppressed.

  • Heart transplant with valve regurgitation from a structurally abnormal valve

Reasons for increased risk:

  • Endothelial disruption
  • High-intensity immunosuppressive therapy
  • Frequent central venous catheter access
  • Frequent endomyocardial biopsies

Conditions where premedication is not recommended

  • Implantable electronic devices (pacemaker)
  • Septal defect closure devices (complete closure achieved)
  • Peripheral vascular grafts and patches (used for hemodialysis)
  • Coronary artery stents or other vascular stents
  • Mitral valve prolapse
  • CNS ventriculoatrial shunts
  • Vena cava filters
  • Pledgets

What does antibiotic prophylaxis prevent?

Premedicating with antibiotics for dental procedures is primarily meant to prevent infective endocarditis. However, it can also be used to prevent prosthetic joint infections but the guidelines have been recommending against this.

Infective endocarditis

The primary purpose of taking antibiotics prophylactically before dental procedures is to prevent infective endocarditis by viridans group streptococcal.

IE is defined as the inflammation of the inner heart linings as well as the valves which separate the four heart chambers. It is primarily caused by bacteria and can have a wide range of consequences.

Complications from infection:

What that translates to is a mortality rate of about 30% in 30 days. Older studies pegged the death rate at 38% which was even more. To put it concisely, you have a substantial chance of dying if you get this infection.

For more information, the AHA has a patient fact sheet on IE.

Prosthetic joint infections

Having a prosthetic joint used to be an indication for taking antibiotics before high risk dental procedures. However, according to the most recent ADA clinical practice guidelines in 2015, it is no longer recommended to premedicate for procedures.

management of prosthetic joint infections - ADA chairside guide

Essentially, the benefits do not outweigh the risks:

  • Studies found no association between dental procedures and prosthetic joint infections.
  • However, for severely immunocompromised patients, the orthopedic surgeon may still advise dental antibiotic prophylaxis.

We still have a lot of patients come in thinking that they need to premedicate before their appointment. The main issue with that is a lack of awareness because the patients are used to premedicating and now they’re being told they don’t need to.

When is premedication necessary?

Antibiotic premedication is recommended for all dental procedures that manipulate the gingival tissue, periapical region of the teeth, or perforations of the oral mucosa.

Affected dental procedures:

Which procedures don’t need it?

Non-invasive procedures such as quick follow ups or limited oral examinations will not require it. Essentially anything that does not manipulate the gum tissue and cause bleeding.


  • Denture adjustment
  • Inserting night guards
  • Changing out Invisalign trays
  • Vitality testing (cold testing or electric pulp testing)

Where can I get antibiotics for prophylaxis?

Prophylactic antibiotics are by prescription only which means that you will need a healthcare professional to prescribe it.

Patients often have two options to get the RX:

  • Dentist. You can ask your dentist to prescribe it and they often do as long as they have your medical history on record stating the need for it.
  • Physician. If the dentist you’re seeing is new, you may want to ask your physician for the prescription. It avoids a lot of paperwork and backforth since you’re already established at your physician’s office but not at the new dentist’s office.

Please do not try to buy it from a third party without a legitimate prescription.

Why is dental antibiotic prophylaxis important?

We’ve put together this guide to provide clarity as to when you should be taking antibiotic premedication and when you shouldn’t. A lot of people are often not up to date with the guidelines due to it changing every so often such as how PJI no longer requires premedicating.

Then there is also the unique encounters which we recounted in the beginning about how a patient thought he was supposed to take 3g of amoxicillin instead of 2g.

Overall, all of this is important information to know because it affects your health. Infective endocarditis has a high mortality rate and you don’t want to end up with it from a dental appointment.


1311 Jackson Ave
Long Island City, NY 11101

Email Us


Dental Services

If you're in NYC and in need of a dentist, our clinical dental practice, 1311 Jackson Ave Dental is accepting new patients.

Our purpose at afterva, is to encourage you to seek in person care with a doctor. It's not meant to be a substitute for medical advice.

A lot of nuances cannot be detected without an in-person clinical exam, which means it is near impossible to diagnose and treat virtually.

sitemap | privacy policy