For an 82-year-old male with altered mental status and a lactate of 5 mmol/L, which intravenous antimicrobial should be administered first?

In this scenario, the patient presents with altered mental status and a significantly elevated lactate level, indicating potential sepsis or a severe infection requiring immediate intervention. When choosing an intravenous antimicrobial to administer first, it's crucial to consider the most effective options for treating possible causes of the patient's condition, particularly infections that could lead to septic shock.

Cefepime is a broad-spectrum cephalosporin antibiotic effective against a wide variety of organisms, including many Gram-negative bacilli and some Gram-positive organisms. In the context of sepsis, where both Gram-negative and some resistant Gram-positive bacteria may be involved, cefepime offers excellent coverage and is a preferred choice in empirical therapy for febrile neutropenia, hospital-acquired infections, and other severe infections. Administering cefepime would help ensure that potentially life-threatening infections are effectively treated while further diagnostic measures are undertaken.

Other options like vancomycin, tobramycin, and azithromycin have specific indications but may not provide as broad a coverage in this emergency context. Vancomycin, while crucial for covering MRSA infections, would not address the broad spectrum of Gram-negative pathogens as effectively as cefepime. Tobramycin, an aminoglycoside