I. Standard Regimen in Patients at Risk (including those with prosthetic heart valves and other high risk patients):

For Penicillin/Ampicillin/Amoxicillin allergic patients:
Erythromycin ethylsuccinate 800 mg or erythromycin stearate 1.0 gm orally 2 hours before a procedure, then one-half the original dose 6 hours after the initial administration…OR…
Clindamycin 300 mg orally 1 hour before a procedure and 150 mg 6 hours after the initial dose.

For Non-Allergic patients:
Amoxicillin 3.0 gm orally one hour before procedure, then 1.5 gm six hours after initial dose.
II. Alternate Prophylactic Regimens in Patients at Risk

For Patients who cannot take oral medications
For Penicillin/Ampicillin/Amoxicillin allergic patients:
Clindamycin 300 mg IV 30 minutes before a procedure and 150 mg IV (or orally) 6 hours after the initial dose.
For Non-Allergic patients:
Ampicillin 2.0 gm IV (or IM) 30 minutes before a procedure, then ampicillin 1.0 gm IV (or IM) OR amoxicillin 1.5 gm orally 6 hours after the initial dose.
For high risk patients who are not candidates for the standard regimen:
For Penicillin/Ampicillin/Amoxicillin allergic patients:
Vancomycin 1.0 gm IV administered over 1 hour, starting one hour before the procedure. No repeat dose is necessary.
For Non-Allergic patients:
Ampicillin 2.0 gm IV (or IM) plus gentamicin 1.5 mg/kg IV (or IM) (not to exceed 80 mg) 30 minutes before the procedure, followed by amoxicillin 1.5 gm orally 6 hours after the initial dose. Alternatively, the parenteral regimen my be repeated 8 hours after the initial dose.

For Children, the doses are:
Amoxicillin: 50 mg/kg initial then 25 mg/kg subsequently
Ampicillin 50 mg/kg initially then 25 mg/kg subsequently
Clindamycin: 10mg/kg initially and 5 mg/kg subsequently
Erythromycin ethylsuccinate and stearate: 20 mg/kg initially then 10 mg/kg subsequently
Gentamicin 2.0 mg/kg initially then 1.0 mg/kg subsequently
Vancomycin 20 mg/kg initially and 10 mg/kg subsequently
The following weight ranges may also be used for the initial pediatric dose of Amoxicillin
<15 kg (33 lbs) ... 750 mg of Amoxicillin orally
15-30 kg (33-66 lbs) … 1.5 gm of Amoxicillin orally
>30 kg (66 lbs) … 3.0 gms (full adult dose)