Antibiotic Prophylactic Regimens for Endocarditis

AMA Recommendations

The antibiotic prophylactic regimens below are recommended by the American Heart Association (AHA) only  for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from infective endocarditis.

For further information on infective endocarditis, see Infective Endocarditis, Pediatric Bacterial Endocarditis, Infectious Endocarditis, and Neurological Sequelae of Infective Endocarditis.

High-Risk Cardiac Conditions

Antibiotic prophylaxis is indicated for the following high-risk cardiac conditions:

• Prosthetic cardiac valve
• History of infective endocarditis (see image below)
• Congenital heart disease (CHD) ( except for the conditions listed, antibiotic prophylaxis is no longer recommended for any other form of CHD): (1) unrepaired cyanotic CHD, including palliative shunts and conduits; (2) completely repaired congenital heart defect with prosthetic material or device, whether placed by surgery or by catheter intervention, during the first 6 months after the procedure; and (3) repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device (which inhibits endothelialization)
• Cardiac transplantation recipients with cardiac valvular disease

  Acute bacterial endocarditis caused by Staphylococcus aureus with aortic valve ring abscess extending into myocardium. Courtesy of Janet Jones, MD, Laboratory Service, Wichita Veterans Administration Medical Center.

Dental Procedures

For patients with high cardiac risk, antibiotic prophylaxis is recommended for alldental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa.

The following dental procedures do not require endocarditis prophylaxis:

• Routine anesthetic injections through noninfected tissue
• Taking 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 or oral mucosa

The findings of one study supported the 2008 National Institute for Health and Clinical Excellence (NICE) guideline recommendations that antibiotic prophylaxis prior to invasive dental procedures was likely to not be of benefit in preventing infective endocarditis in patients with a history of rheumatic fever or a heart murmur. The authors did suggest though that patients at highest risk (eg, those with prosthetic valves) still might benefit. Note that the study was conducted in England; therefore, a limitation of the study is the external generalizability of the findings to other countries.

Dayer et al investigated changes in the prescribing of antibiotic prophylaxis and the incidence of infective endocarditis in England since the introduction of the 2008 NICE guidelines. Although the data form the study did not establish a causal association, prescriptions of antibiotic prophylaxis have fallen substantially and the incidence of infective endocarditis has increased significantly in England since introduction of the 2008 NICE guidelines.

Respiratory Tract, Infected Skin, Skin Structures, or Musculoskeletal Tissue Procedures

Antibiotic prophylaxis is recommended for invasive respiratory tract procedures that involve incision or biopsy of the respiratory mucosa (eg, tonsillectomy, adenoidectomy). Antibiotic prophylaxis is not  recommended for bronchoscopy unless the procedure involves incision of the respiratory tract mucosa. For invasive respiratory tract procedures to treat an established infection (eg, drainage of abscess, empyema), administer an antibiotic that is active against Streptococcus viridans.

Patients with high cardiac risk who undergo a surgical procedure that involves infected skin, skin structure, or musculoskeletal tissue should receive an agent active against staphylococci and beta-hemolytic streptococci (eg, antistaphylococcal penicillin, cephalosporin).

If the causative organism of respiratory, skin, skin structure, or musculoskeletal infection is known or suspected to be Staphylococcus aureus, administer an antistaphylococcal penicillin or cephalosporin, or vancomycin (if patient is unable to tolerate beta-lactam antibiotics). Vancomycin is recommended for known or suspected methicillin-resistant strains of S aureus.

Genitourinary or GI Tract Procedures

Antibiotics are no longer recommended for endocarditis prophylaxis for patients undergoing genitourinary or gastrointestinal tract procedures.

Orthopaedic Guidelines

A new clinical practice guideline produced jointly by the American Academy of Orthopaedic Surgeons (AAOS) and the American Dental Association (ADA) was published in April 2013. The recommendation proposes that the practitioner consider changing the long-standing practice of routinely prescribing prophylactic antibiotic for patients with orthopaedic implants who undergo dental procedures. The grade of recommendation is listed as limited, indicating there is unconvincing evidence. The previous guideline from 2003 was updated in 2009 and endorsed antibiotic prophylaxis before dental procedures for all patients with prosthetic joints, with no 2-year time limit. The 2009 guideline position has been criticized for excessive and unwarranted antibiotic use.

Treatment Regimens

The most common cause of endocarditis for dental, oral, respiratory tract, or esophageal procedures is S viridans (alpha-hemolytic streptococci). Antibiotic regimens for endocarditis prophylaxis are directed toward S viridans, and the recommended standard prophylactic regimen is a single dose of oral amoxicillin. Amoxicillin, ampicillin, and penicillin V are equally effective in vitro against alpha-hemolytic streptococci; however, amoxicillin is preferred because of superior gastrointestinal absorption that provides higher and more sustained serum levels.

All doses shown below are administered once as a single dose 30-60 min before the procedure.

Standard general prophylaxis

Amoxicillin

Adult dose: 2 g PO

Pediatric dose: 50 mg/kg PO; not to exceed 2 g/dose

Unable to take oral medication

Ampicillin

Adult dose: 2 g IV/IM

Pediatric dose: 50 mg/kg IV/IM; not to exceed 2 g/dose

Allergic to penicillin

Clindamycin

Adult dose: 600 mg PO

Pediatric dose: 20 mg/kg PO; not to exceed 600 mg/dose

Allergic to penicillin

Cephalexin or other first- or second-generation oral cephalosporin in equivalent dose (do not use cephalosporins in patients with a history of immediate-type hypersensitivity penicillin allergy, such as urticaria, angioedema, anaphylaxis)

Adult dose: 2 g PO

Pediatric dose: 50 mg/kg PO; not to exceed 2 g/dose

Azithromycin or clarithromycin

Adult dose: 500 mg PO

Pediatric dose: 15 mg/kg PO; not to exceed 500 mg/dose

Allergic to penicillin and unable to take oral medication

Clindamycin

Adult dose: 600 mg IV

Pediatric dose: 20 mg/kg IV; not to exceed 600 mg/dose

Cefazolin or ceftriaxone (do not use cephalosporins in patients with a history ofimmediate-type hypersensitivity penicillin allergy, such as urticaria, angioedema,anaphylaxis)

Adult dose: 1 g IV/IM

Pediatric dose: 50 mg/kg IV/IM; not to exceed 1 g/dose