Antibiotic Prophylaxis for Bacterial Endocarditis

Bacterial endocarditis is a microbial infection of the inner layer of the cardiac muscle (endocardium). Patients with congenital or acquired cardiac defects are believed to be at high risk for developing bacterial endocarditis if a (dental) procedure causes a transient bacteremia. Blood-bourne bacteria may lodge on the abnormal endocardium or heart valves, causing endocardial infection. In 2007 the American Heart Association revised its 1997 guidelines on prevention of bacterial endocarditis. The primary reasons for the revision include:

  • Bacterial endocarditis is much more likely to result from frequent exposure to random bacteremias associated with daily activities than form bacteremia caused by dental, GI tract, or GU tract procedures.
  • Prophylaxis may prevent an exceedingly small number of cases bacterial endocarditis, in individuals who undergo dental, GI tract or GU tract procedures.
  • The risk of antibiotic associated adverse events exceeds the benefit from prophylactic antibiotic therapy.
  • Maintenance of optimal oral health and hygiene may reduce the incidence of bacteremia from daily activities and is more effective than prophylactic antibiotics for a dental procedure for reducing the risk of bacterial endocarditis.

The revised guidelines clarified when antibiotic prophylaxis is/is not recommended, i.e.,

  1. Only an extremely small number of cases might be prevented by antibiotic prophylaxis.
  2. Antibiotic prophylaxis for dental procedures is recommended only for patients with underlying cardiac conditions associated with the highest risk of adverse outcomes from bacterial endocarditis.
  3. For patients with these underlying cardiac conditions, prophylaxis is recommended for all dental procedures that involve manipulation of gingival tissues or the periapical region of teeth or perforation of the oral mucosa.
  4. Prophylaxis is not recommended based solely on an increased lifetime risk of acquiring bacterial endocarditis

Specific recommendations from the 2007 AHA guidelines on prevention of bacterial endocarditis are included in the following tables. Consultation with the patient’s physician is recommended to determine the patient’s susceptibility to bacterial endocarditis.

Table 3. Cardiac Conditions Associated with the Highest Risk of Adverse Outcomes from Endocarditis for Which Prophylaxis Prior to Dental Procedures is Recommended.

  • Prosthetic cardiac valve
  • Previous bacterial endocarditis
  • Congenital heart disease (CHD)
  • Unrepaired cyanotic CHD, including palliative shunts and conduits
  • Completely repaired congenital heart defects with prosthetic material or devices, whether placed by surgery or catheter intervention within the first 6 months after the procedure
  • Repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device (which inhibit endothelialization)
  • Cardiac transplantation recipients who develop cardiac valvuopathy

Table 4. Dental Procedures for Which Endocarditis Prophylaxis is/is not Recommended for Patients in Table 3.

  • All dental procedures that involve manipulation of gingival tissue or the periapical region of the teeth or perforation of the oral mucosa
Not recommended
  • Routine anesthetic injections through no infected tissue
  • Dental radiographs
  • Placement of removable prosthodontic or orthodontic appliances
  • Adjustment of orthodontic appliances
  • Placement of orthodontic brackets
  • Shedding of deciduous teeth
  • Bleeding from trauma to the lips and tongue

Table 5. Regimens for Dental Procedures.

Administer single dose 30 to 60 minutes before procedure
Situation Agent Adults Children
Oral Amoxicillin 2 gm 50 mg/kg
Unable to take oral medication Ampicillin
Cefazolin or ceftriaxone
2 gm IM or IV

1gm IM or IV
50 mg/kg IM or IV

50 mg/kg IM or IV
Allergic to penicillins or ampicillin-oral Cephalexin
Azithromycin or clarithromycin
2 gm

600 mg

500 mg
50 mg/kg

20 mg/kg

15 mg/kg
Allergic to penicillin or ampicillin and unable to take oral medication Cefazolin or ceftriaxone
1 gm IM or IV

600 mg IM or IV
50 mg/kg IM or IV

20 mg/kg IM or IV