What is the first line empirical treatment for native valve endocarditis in a patient with intravenous (IV) drug use?

From the Guidelines

For empirical treatment of native valve endocarditis in a patient with intravenous (IV) drug use, the recommended regimen is vancomycin 30-60 mg/kg/day IV in 2-3 doses plus gentamicin 3 mg/kg/day IV or IM in 1 dose, as this combination provides broad coverage against the most likely pathogens, including Staphylococcus aureus and other potential causative organisms. This recommendation is based on the 2015 ESC guidelines for the management of infective endocarditis 1. The choice of vancomycin and gentamicin is supported by the guidelines, which suggest this combination for initial empirical treatment of infective endocarditis in acute severely ill patients, particularly those with a history of IV drug use. Key considerations in the management of these patients include:

• Obtaining blood cultures before starting antibiotics, but not delaying treatment if the patient is unstable
• Monitoring gentamicin and vancomycin dosages closely to avoid toxicity
• Adjusting the vancomycin dosage to maintain trough levels within a therapeutic range
• Continuing the antibiotic regimen for 4-6 weeks, with potential de-escalation based on blood culture results and susceptibility testing
• Close monitoring for complications, including heart failure, embolic events, and persistent bacteremia
• Performing echocardiography (preferably transesophageal) to assess valve damage and vegetations
• Arranging addiction treatment referral as part of comprehensive care. It is essential to note that IV drug users are at higher risk for Staphylococcus aureus endocarditis, particularly right-sided infections involving the tricuspid valve, and require individualized care and careful monitoring 1.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Empirical Treatment for Native Valve Endocarditis

The first line empirical treatment for native valve endocarditis in a patient with intravenous (IV) drug use is as follows:

• For native valve endocarditis, the empirical treatment should be targeted toward the most likely pathogens, including staphylococci, streptococci, and enterococci species 2
• Vancomycin is recommended as the empirical therapy for native valve endocarditis, especially in cases where methicillin-resistant Staphylococcus aureus (MRSA) is suspected 3
• The treatment regimen may include vancomycin 30 mg/kg/day IV in 2-4 doses for 4-6 weeks, with the addition of rifampin 600-900 mg/day orally in some cases 4
• For right-sided native valve endocarditis in IV drug users, a less vigorous therapy may be considered, but the specific regimen should be determined based on the causative microorganism and the patient's clinical status 5

Considerations for Treatment

The following factors should be considered when determining the treatment regimen:

• The type and location of the valve involved (native, prosthetic, left or right sided) 2
• The clinical status of the patient and the likelihood of clinical success 2
• The presence of underlying conditions, such as intravenous drug abuse 4
• The results of blood cultures and susceptibility testing, which should guide the selection of antibiotics 6, 4