Nafcillin Injection, USP is a sterile injectable product containing nafcillin which is added as Nafcillin Sodium, USP, a semisynthetic penicillin derived from the penicillin nucleus, 6aminopenicillanic acid. The chemical name of nafcillin sodium is Monosodium (2S,5R,6R)-6-(2ethoxy-1-naphthamido)-3,3-dimethyl-7-oxo-4-thia-1- azabicyclo[3.2.0]heptane-2-carboxylate monohydrate. It is resistant to inactivation by the enzyme penicillinase (beta-lactamase). The molecular formula of Nafcillin Sodium, USP is C₂₁H₂₁N₂NaO₅S•H₂O. The molecular weight is 454.48. The structural formula of nafcillin sodium is as follows:

Nafcillin Injection, USP is a frozen, iso-osmotic, sterile, nonpyrogenic premixed 50 mL or 100 mL solution containing 1 g or 2 g of nafcillin, respectively, added as Nafcillin Sodium, USP. Dextrose, USP has been added to the above dosages to adjust osmolality (approximately 1.8 g and 3.6 g as dextrose hydrous to the 1 g and 2 g dosages, respectively). Sodium Citrate Hydrous, USP has been added as a buffer (approximately 90 mg and 180 mg to the 1 g and 2 g dosages, respectively). The pH has been adjusted with hydrochloric acid and may have been adjusted with sodium hydroxide. The pH is 6.5 (6.0 to 8.5). The solution is intended for intravenous use after thawing to room temperature.

This GALAXY container is fabricated from a specially designed multilayer plastic (PL 2040). Solutions are in contact with the polyethylene layer of this container and can leach out certain chemical components of the plastic in very small amounts within the expiration period. The suitability of the plastic has been confirmed in tests in animals according to the USP biological tests for plastic containers, as well as by tissue culture toxicity studies.

Last reviewed on RxList: 11/18/2011
This monograph has been modified to include the generic and brand name in many instances.