Infective Endocarditis Medication

Updated: Jul 01, 2022
  • Author: John L Brusch, MD, FACP; Chief Editor: Michael Stuart Bronze, MD  more...
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Medication Summary

Antibiotics are the mainstay of treatment for infective endocarditis (IE). Goals to achieve to maximize clinical outcomes are early diagnosis, accurate microorganism identification, reliable susceptibility testing, prolonged intravenous (IV) administration of bactericidal antimicrobial agents, proper monitoring of potentially toxic antimicrobial regimens, and aggressive surgical management of correctable mechanical complications.



Penicillin G (Pfizerpen)

Penicillin G is used for IE caused by S viridans or S bovis with a penicillin G minimum inhibitory concentration (MIC) of 0.1 mcg/mL or less.

Oxacillin (Bactocil in Dextrose)

Oxacillin is a bactericidal antibiotic that inhibits cell wall synthesis. It is used to treat infections caused by penicillinase-producing staphylococci. It is used to initiate therapy when MSSA infection is present.


Ceftriaxone is given as once-daily treatment of S viridans or HACEK (ie, H aphrophilus, A actinomycetemcomitans, C hominis, E corrodens, K kingae) IE. It is a third-generation cephalosporin with broad-spectrum gram-negative activity. It has lower efficacy against gram-positive organisms and higher efficacy against resistant organisms. It arrests bacterial growth by binding to one or more penicillin-binding proteins.


Ampicillin is used for treatment of enterococcal IE, IE caused by HACEK organisms, or as a penicillin G substitute for penicillin-susceptible organisms.

For enterococcal endocarditis, duration of treatment is 4-6 weeks in combination with gentamicin.


Cefazolin is a first-generation cephalosporin that is used for staphylococcal endocarditis susceptible to methicillin/oxacillin. It may be substituted for penicillin G or ampicillin for penicillin-susceptible streptococcal endocarditis. It is used if the patient develops a mild rash to penicillins but no anaphylaxis or severe immediate hypersensitivity reactions.

Nafcillin (Nallpen in Dextrose)

Nafcillin is used for staphylococcal IE caused by organisms susceptible to methicillin/oxacillin.



Meropenem (Merrem IV)

Meropenem inhibits cell-wall synthesis by binding to penicillin-binding proteins. It is resistant to most beta-lactamases. 




Inhibits protein synthesis and thus bacterial growth by binding to 30S and possibly 50S ribosomal subunits of susceptible bacteria. 

Doxycycline (Adoxa, Doryx, Monodox, Vibramycin)

Doxycycline is a broad-spectrum, synthetically derived bacteriostatic antibiotic in the tetracycline class. It is almost completely absorbed, concentrates in bile, and is excreted in urine and feces as a biologically active metabolite in high concentrations. It inhibits protein synthesis and, thus, bacterial growth by binding to the 30S and possibly 50S ribosomal subunits of susceptible bacteria. It may block dissociation of peptidyl t-RNA from ribosomes, causing RNA-dependent protein synthesis to arrest.



Dalbavancin (Dalvance)

Dalbavancin is a lipoglycopeptide antibiotic that interferes with cell wall synthesis by binding to D-alanyl-D-alanine terminus of the stem pentapeptide in nascent cell wall peptidoglycan, thus preventing cross-linking. Bactericidal in vitro against Staphylococcus aureus and Streptococcus pyogenes at concentrations obtained in humans. 


Vancomycin is no longer the drug of choice for patients who are allergic to penicillin who have streptococcal or enterococcal endocarditis, those with methicillin-resistant S aureus (MRSA) IE, and those with other beta-lactam–resistant gram-positive IE infections.

It is important to achieve adequate trough levels of 15-20 mcg/mL. If theMIC of the isolate is 2 mcg/mL or greater, vancomycin should not be administered.

The duration of treatment is 4 weeks in penicillin-susceptible streptococcal IE and 4-6 weeks for staphylococcal infections, prosthetic valve infections, or enterococcal IE.




Gentamicin is an aminoglycoside used in combination therapy to attain bactericidal activity against enterococci and resistant streptococcal species, to shorten treatment of penicillin-susceptible streptococcal IE, and for prosthetic staphylococcal IE.

The duration of treatment is 2 weeks for penicillin-susceptible streptococcal IE and 4-6 weeks for penicillin-resistant streptococci and enterococci.


Streptomycin is an aminoglycoside antibiotic that has bacteriocidal activity and acts by inhibiting protein synthesis. It may be used for the treatment of streptococcal or enterococcal endocarditis


Antibiotics, Other

Linezolid (Zyvox)

Linezolid prevents formation of functional 70S initiation complex, which is essential for bacterial translation process. It is bacteriostatic against enterococci and staphylococci and bactericidal against most strains of streptococci. It is used as an alternative in patients allergic to vancomycin and for treatment of vancomycin-resistant enterococci (VRE). 

Rifampin (Rifadin)

Rifampin is used synergistically in the treatment of staphylococcal infections associated with a foreign body, such as a prosthetic heart valve.

Rifampin inhibits DNA-dependent RNA polymerase activity in susceptible cells. Specifically, it interacts with bacterial RNA polymerase but does not inhibit the mammalian enzyme. Cross-resistance has been shown only with other rifamycins.

Daptomycin (Cubicin)

Daptomycin is a cyclic lipopeptide antibiotic that is used for Staphylococcus aureus bacteremia, including those with right-sided infective endocarditis caused by MSSA or MRSA. There is a risk of developing eosinophilic pneumonia with daptomycin use. Immediate discontinuation of daptomycin is recommended if eosinophilic pneumonia is suspected.