As a clinical pharmacist, you will see changes in endocarditis treatment due to new guidelines. Infective endocarditis (IE) refers to infection of the endocardial surface of the heart, most often the heart valves, particularly prosthetic heart valves.
The great majority of cases are caused by staphylococci or streptococci and diagnosis is based on the presence of compatible clinical features, microbiologic data (obtain 3 sets of blood cultures when considering the diagnosis of IE in any patient), and echocardiography. The definitive antibiotic regimen and duration of therapy varies with causative pathogen, antibiotic susceptibility, and the absence or presence of prosthetic material, such as a prosthetic valve. Empiric antibiotic regimens vary based on the valve type (see Table 1).
| Table (1). Empiric antibiotic regimens vary based on the valve type (dosing based on normal renal function) | |
|---|---|
| Valve Type | Antibiotic Regimens |
| Native valve endocarditis | consider vancomycin 15-20 mg/kg IV every 8-12 hours (a target trough concentration of 15-20 mcg/mL) plus either ceftriaxone 2 g IV every 24 hours OR gentamicin 1 mg/kg IV or intramuscularly every 8 hours. |
| Prosthetic valve endocarditis | consider vancomycin 15-20 mg/kg IV every 8-12 hours (a target trough concentration of 15-20 mcg/mL) plus gentamicin 1 mg/kg IV every 8 hours plus rifampin 300 mg orally or IV every 8 hours. |
| Antifungal therapy is generally not started empirically. | |
Be aware of the latest recommendations to help your stable endocarditis patients complete IV antibiotics at home. According to type of bacteria, start treatment...
- Enterococcal endocarditis. Expect to see ampicillin PLUS ceftriaxone for 6 weeks in most patients. This combo is as effective as ampicillin PLUS gentamicin and causes less nephrotoxicity. But ampicillin or penicillin plus gentamicin may be used for just 4 weeks in patients with NATIVE valve disease and symptoms for less than 3 months, who aren't at risk for nephrotoxicity.
- Staphylococcal endocarditis. Don't expect to see much synergistic gentamicin used in NATIVE valve disease anymore. It DOESN'T improve outcomes and increases the risk of nephrotoxicity. Instead, expect nafcillin or oxacillin to be used for 6 weeks. For PROSTHETIC valve disease, expect nafcillin or oxacillin to be used for at least 6 weeks plus synergistic rifampin for at least 6 weeks and gentamicin for 2 weeks.
- Streptococcal endocarditis. Expect to continue to see penicillin G (Pencitard) or ceftriaxone plus or minus gentamicin for 2 to 6 weeks in most patients. For ALL gram-positive endocarditis, be aware that beta-lactams are preferred over vancomycin, except in patients with beta-lactam associated anaphylaxis or other more resistant organisms such as MRSA.
- Gram-negative endocarditis. Expect to see ceftriaxone for 4 to 6 weeks in most patients and 6 weeks used for prosthetic valves.
Provide early follow-up after hospital discharge. Ask your staff to call patients within 2 days of discharge, and see patients within 7 to 14 days. Monitor for antibiotic toxicity. For example, routinely check renal function, CBC, and antibiotic levels (gentamicin, vancomycin, etc).
REFERENCES
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Baddour LM, Wilson WR, Bayer AS, Fowler VG Jr, Tleyjeh IM, Rybak MJ, Barsic B, Lockhart PB, Gewitz MH, Levison ME, Bolger AF, Steckelberg JM, Baltimore RS, Fink AM, O'Gara P, Taubert KA; American Heart Association Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease of the Council on Cardiovascular Disease in the Young, Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and Stroke Council. Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications: A Scientific Statement for Healthcare Professionals From the American Heart Association. Circulation. 2015 Oct 13;132(15):1435-86. Available at: https://www.ahajournals.org/doi/10.1161/CIR.0000000000000296
Baddour LM, Wilson WR, Bayer AS, Fowler VG Jr, Bolger AF, Levison ME, Ferrieri P, Gerber MA, Tani LY, Gewitz MH, Tong DC, Steckelberg JM, Baltimore RS, Shulman ST, Burns JC, Falace DA, Newburger JW, Pallasch TJ, Takahashi M, Taubert KA; Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease; Council on Cardiovascular Disease in the Young; Councils on Clinical Cardiology, Stroke, and Cardiovascular Surgery and Anesthesia; American Heart Association; Infectious Diseases Society of America. Infective endocarditis: diagnosis, antimicrobial therapy, and management of complications: a statement for healthcare professionals from the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, and the Councils on Clinical Cardiology, Stroke, and Cardiovascular Surgery and Anesthesia, American Heart Association: endorsed by the Infectious Diseases Society of America. Circulation. 2005 Jun 14;111(23):e394-434. Available at: https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.105.165564