title: Unexplained hypoxia in an in-flight emergency.
abstract: BACKGROUND
  The use of over-the-counter medications and nutritional supplements is prohibited while flying without approval from an aeromedical professional. Despite prohibition, the use of nutritional supplements is common in aircrew due to the perception that these supplements are harmless; in reality, the use of nutritional supplements may be more dangerous than the use of traditional medications. Multiple case reports of adverse neurologic and cardiovascular events associated with the use of specific supplements led the FDA to ban ephedra in 2004 and DMAA in 2012, both marketed as "natural stimulants." These incidents are sobering reminders of the lack of safety data on commonly marketed nutritional supplements. There are few, if any, case reports or clinical trials addressing the safety of common nutritional supplements in flight.
  
  
  METHODS
  This is a case of an aircrew member who experienced hypoxia during an in-flight emergency. He underwent thorough medical evaluation to determine the cause of his hypoxic event and ultimately admitted to the use of a pre-workout supplement: C4 Extreme. He was exposed to simulated altitude both on and off of the supplement and was found to have an improved tolerance to a hypoxic environment after discontinuation.
  
  
  CONCLUSIONS
  While not conclusive, the data suggests that the use of C4 Extreme may be implicated in this aircrewman's increased susceptibility to hypoxia. A randomized controlled trial would be required to determine if this is a patient-specific response or if this is a normal physiologic response to the use of this and similar supplements.
authors.forename: Debra D
authors.initials: DD
authors.lastname: Coffey
mesh_terms: D000328:Adult; D001359:Aviation; D019587:Dietary Supplements / Q000009:adverse effects*; D004630:Emergencies; D006801:Humans; D000860:Hypoxia / Q000209:etiology*; D008297:Male