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Medically Compromised Patient Care

Course Number: 628

Antibiotic Prophylaxis Guidelines - High Risk Cardiac Patients

The AHA and ADA have conducted extensive research to determine appropriate antibiotic premedication guidelines for high-risk cardiac patients. Table 3 outlines the specific antibiotics that can be used in situations, such as patients who are unable to take oral medication or have an allergy to penicillin. The table also lists the recommended dosages for adults and children.

Table 3. Antibiotics & Dosing for High Risk Cardiac Patients (1,10)
Situation AgentAdultsChildren
  • Amoxicillin
2 g 50mg/kg
Unable to take oral medication
  • Ampicillin or
  • Cefazolin or ceftriaxone
2 g IM or IV
1 g IM or IV

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

Allergic to penicillins or ampicillin-oral
  • Doxycyline
  • Azithromycin/ Clarithromycin
  • Cephalexin*
100 mg
500 mg

2 g
50 mg/kg
20 mg/kg

Allergic to penicillins or ampicillin OR unable to take oral medication
  • Cefazolin or ceftriaxone
1 g IM or IV
50 mg/kg IM or IV
* Cephalosporins should not be used in an individual with a history of anaphylaxis, angioedema, or urticaria with penicillin or ampicillin.
ce628 - Reminder - 2

The reason amoxicillin is the first-line drug for antibiotic prophylaxis, is because it can effectively kill the three types of microorganisms that most often cause infective endocarditis. These microorganisms are 1) staphylococcus aureus, which generally inhabits the skin, 2) viridans group streptococci (alpha-hemolytic), which include microorganisms from the mouth and the pharynx, and 3) enterococci from the G.I. tract. The dental health professionals’ primary concern involves the second group of streptococci.

ce628 - Reminder - 3

When a patient takes antibiotic premedication, it must be taken 30-60 minutes before dental treatment in order to be effective. It takes at least 60 minutes for the elevated amounts of antibiotic to be present in the patient’s blood. If the antibiotic is inadvertently not administered prior to the procedure, it can be given up to 2 hours after the procedure. However, that is not ideal. If follow-up treatment is needed in <10 days, a different antibiotic must be given. If the patient is on an antibiotic for another reason (e.g., sinus infection), it does NOT cover their prophylactic antibiotic requirement for dental treatment. They must be premedicated with a different antibiotic than the one they are currently using. Finally, if amoxicillin has been administered and the dental procedure will last longer than 6 hours, another full dose must be given.