and other studies, dalbavancin is more potent and bactericidal and therefore requires lower concentrations than vancomycin against these organisms. Dalbavancin also shows in vitro activity against vancomycin-susceptible Enterococcus faecium and Enterococcus faecalis. Other Gram-positive organisms belonging to the Bacillus spp., Listeria spp., and Corynebacterium spp. may show in vitro susceptibility, and dalbavancin may exhibit activity against enterococci expressing the VanB or VanC phenotype of acquired resistance against vancomycin. There is no clinically significant activity against Gram-negative bacteria. Two trials, DISCOVER 1 and DISCOVER 2, demonstrated noninferiority of dalbavancin compared to vancomycin/linezolid in the treatment of ABSSSI. Patients were randomly assigned to receive two doses of dalbavancin on days 1 and 8, or to receive intravenous vancomycin for at least 3 days with the option of switching to oral linezolid to complete 10 to 14 days of therapy. Investigators assessed the cessation of spread of infection-related erythema and the absence of fever at 48 to 72 hours as the primary endpoint and found that once-weekly dalbavancin was as effective as twice-daily intravenous vancomycin followed by oral linezolid. This once-weekly dosing regimen may offer an advantageous treatment option compared to daily or twice-daily dosing. Contraindications Hypersensitivity to dalbavancin can occur, causing issues such as skin reactions or anaphylaxis. Caution is advised for patients with known hypersensitivity to other glycopeptides. There is currently no data on cross-reactivity between dalbavancin and vancomycin. Side effects The most common adverse reactions encountered in Phase II and Phase III trials were nausea (5.5%), headache (4.7%), and diarrhea (4.4%), as well as rash (2.7%) and itchiness (2.1%). Other less frequent but serious adverse reactions included hematologic disorders, hepatotoxicity, Clostridium difficile colitis, bronchospasm, infusion-related reactions including Red Man Syndrome, and anaphylactic shock. In trials, dalbavancin was associated with higher rates of hemorrhagic events compared to comparator groups and should be a precaution in patients undergoing surgery or taking anticoagulants. Patients on dalbavancin also had post-baseline alanine aminotransferase (ALT) levels that were 3 times the upper normal limit, some even having elevations 10 times the upper normal limit; however, eight of the twelve dalbavancin-treated patients had comorbid conditions that could affect their ALT, compared to only one patient in the comparator group. There is no evidence of ototoxicity associated with dalbavancin. Drug interactions Clinical drug-drug interactions with dalbavancin have not been studied, and dalbavancin does not appear to interact with cytochrome P450 substrates, inhibitors, or inducers. It was found to