A 24-year-old male graduate student presents with debilitating anxiety strictly limited to public speaking situations, reporting pounding heart, trembling hands, and a shaky voice during presentations that are affecting his academic performance. His history includes childhood-onset asthma currently well-controlled with an albuterol rescue inhaler used once monthly. The PMHNP considers propranolol as-needed for performance anxiety. Which of the following is most important to evaluate before prescribing?