The document summarizes changes over time to guidelines from the American Heart Association regarding antibiotic prophylaxis for infective endocarditis. The key changes are: (1) prophylaxis is now only recommended for those cardiac conditions with the most serious outcomes from IE, (2) prophylaxis is recommended for almost all dental procedures for at-risk individuals, and (3) timing of antibiotics is 30-60 minutes before a procedure rather than both before and after. Prophylaxis is no longer routinely recommended for other conditions, gastrointestinal/genitourinary procedures, or daily activities that may cause minor bacteremia, as the risks of antibiotics outweigh the small potential benefits of prevention in those cases.

1. Prevention of Infective Endocarditis Guidelines From the American Heart Association Circulation: April 19, 2007 http://ahajournals.org

2. Summary of AHA-Recommended Antibiotic Regimens From 1955 to 1997 for Dental/Respiratory Tract Procedures Year Primary Regimens for Dental Procedures 1955 Aqueous penicillin 600 000 U and procaine penicillin 600 000 U in oil containing 2% aluminum monostearate administered IM 30 minutes before the operative procedure 1957 For 2 days before surgery, penicillin 200 000 to 250000 U by mouth 4 times per day. On day of surgery, aqueous penicillin 600 000 U with procaine penicillin 600000 U IM 30 to 60 minutes before surgery. For 2 days after, 200000 to 250000 U by mouth 4 times per day. 1960 Step I: prophylaxis 2 days before surgery with procaine penicillin 600 000 U IM on each day Step II: day of surgery: procaine penicillin 600 000 U IM supplemented by crystalline penicillin 600 000 U IM 1 hour before surgical procedure Step III: for 2 days after surgery: procaine penicillin 600000 U IM each day

3. Continued…. 1965 Day of procedure: procaine penicillin 600 000 U, supplemented by crystalline penicillin 600 000 U IM 1 to 2 hours before the procedure For 2 days after procedure: procaine penicillin 600 000 U IM each day 1972 Procaine penicillin G 600 000 U mixed with crystalline penicillin G 200 000 U IM 1 hour before procedure and once daily for the 2 days after the procedure 1977 Aqueous crystalline penicillin G (1 000 000 U IM) mixed with procaine penicillin G (600 000 U IM) 30 minutes to 1 hour before procedure and then penicillin V 500 mg orally every 6 hours for 8 doses. 1984 Penicillin V 2 g orally 1 hour before, then 1 g 6 hours after initial dose 1990 Amoxicillin 3 g orally 1 hour before procedure, then 1.5 g 6 hours after initial dose 1997 Amoxicillin 2 g orally 1 hour before procedure

4. Reasons for Revision of the IE Prophylaxis Guidelines IE is much more likely to results from frequent exposure to random bacteremias associated with daily activities than from bacteremia caused by a dental, GI tract, or GU tract procedure. Prophylaxis may prevent an exceedingly small number of cases of IE, if any, in individuals who undergo a dental, GI tract, or GU tract procedure. The risk of antibiotic-associated adverse events exceeds the benefit, if any, from prophylactic antibiotic therapy. Maintenance of optimal oral health and hygiene may reduce the incidence of bacteremia from daily activities and is more important than prophylactic antibiotics for a dental procedure to reduce the risk of IE.

5. Summary of Changes From the 1997 Guidelines A significant reduction in the numbers and types of cardiac conditions for which antibiotic prophylaxis is recommended (only those with the most serious adverse outcomes of IE) A significant increase in the types of dental procedures recommended for prophylaxis in at-risk individuals (almost all dental procedures) A minor modification in the timing of antibiotic administration (30-60 minutes prior)

6. Continued.. Respiratory tract procedures Antibiotic prophylaxis may be considered for patients who undergo an invasive procedure of the respiratory tract that involves incision or biopsy of the respiratory mucosa, such as tonsillectomy and adenoidectomy GI or GU procedures: The administration of prophylactic antibiotics solely to prevent endocarditis is not recommended for patients who undergo GU or GI tract procedures, including diagnostic esophagogastroduodenoscopy or colonoscopy

7. Cardiac Conditions for Which Prophylaxis of IE is Recommended Prosthetic cardiac valve Previous infective endocarditis Congenital heart disease (CHD) [except for the conditions listed below, Antibiotic prophylaxis is no longer recommended for any other form of CHD] Unrepaired cyanotic CHD, including those with palliative shunts and conduits Completely repaired CHD with prosthetic material or device either by surgery or catheter intervention during first 6 months after procedure (to allow time for endothelial covering of the material) 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 who develop cardiac valvulopathy

8. Conditions for which prophylaxis is no longer recommended (1997 moderate risk conditions) Mitral valve prolapse with regurgitation Rheumatic heart disease and other types of acquired valvular heart disease (e.g. SLE) Ventricular septal defect Atrial septal defect Hypertrophic cardiomyopathy

9. Dental Procedures for Which Endocarditis Prophylaxis is Recommended All dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa Except the following: Routine anesthetic injections through non-infected tissue Taking dental radiographs Placement of removable prosthodontic or orthodontic appliances Adjustment of orthodontic appliances Shedding of deciduous teeth and bleeding from trauma to the lips or oral mucosa

10. Regimens for a Dental Procedure 50 mg/kg IM or IV 2 gm IM or IV 1 gm IM or IV Ampicillin or cephazolin or cephtriaxone Unable to take oral medication 50 mg/kg IM or IV 20 mg/kg IM or IV 1 gm IM or IV 600 mg IM or IV Cephazolinn or cephtriaxone Clindamycin phosphate Allergic to penicillins or ampicillin and unable to take oral medication 50 mg/kg 20 mg/kg 15 mg/kg 15 mg/kg 2 gm 600 mg 500 mg 500 mg Cephalexin or Clindamycin or Azithromycin or Clarithromycin Allergic to penicillin or ampicillin Oral 50 mg/kg 2 gm Children Adults Amoxicillin Oral Regimen-Single dose 30-60 minutes before procedure Agent Situation

11. Forgot to give antibiotics to the patient If the dosage of antibiotic is inadvertently not administered before the procedure, the dosage may be administered up to 2 hours after the procedure. However, the administration of the dosage after the procedure should be considered only when the patient did not receive the pre-procedure dose

12. For patients already taking penicillin or amoxicillin (e.g. prevention of acute Rheumatic fever, treatment of sinusitis) In such cases , due to the likelihood of the presence of penicillin-resistant bacteria in the oral flora, the provider should select either clindamycin, azithromycin, or clarithromycin for IE prophylaxis for a dental procedure

13. Summary Bacteremia resulting from daily activities is much more likely to cause IE than bacteremia associated with a dental procedure. Only an extremely small number of cases of IE might be prevented by antibiotic prophylaxis even if prophylaxis is 100% effective. Antibiotic prophylaxis is not recommended based solely on an increased lifetime risk of acquisition of IE. Antibiotic prophylaxis is no longer recommended for any other form of CHD and other Valvular heart disease except as mentioned above

14. Antibiotic prophylaxis is reasonable for all dental procedures that involve manipulation of gingival tissues or periapical region of teeth or perforation of oral mucosa only for patients with underlying high risk cardiac conditions. Antibiotic prophylaxis is reasonable for procedures on respiratory tract or infected skin, skin structures, or musculoskeletal tissue only for patients with underlying high risk cardiac conditions. Antibiotic prophylaxis solely to prevent IE is not recommended for GU or GI tract procedures.

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