Combination products are generally classified by their essential character or by the active ingredient that drives the primary therapeutic action. If the hormone or endocrine substance is the principal active ingredient, classification under 300439 is appropriate. However, if the combination also contains an antibiotic, a different heading applies. For novel combinations, a CBP binding ruling is the most reliable path to correct classification.

Both epinephrine and vasopressin injectables have experienced recurring US drug shortages, partly due to manufacturing concentration and sterile injectable production complexity. Importers and hospital procurement teams should monitor FDA's drug shortage database and maintain visibility into their supplier's production capacity and FDA inspection history. A facility placed on import alert can disrupt supply with little warning, so qualifying backup suppliers in advance is advisable.