Promethazine Effects on Motion Sickness During Altered Gravity Induced by Parabolic Flight.

Area of Science:

• Space Medicine
• Aerospace Physiology
• Human Factors in Aviation

Background:

• Space motion sickness is a common issue for astronauts, impacting performance and safety.
• Existing pharmaceutical countermeasures for space motion sickness lack extensive study in partial gravity environments.

Purpose of the Study:

• To investigate the efficacy of oral promethazine in mitigating space motion sickness.
• To assess promethazine's effects on motion sickness symptoms during parabolic flight, simulating both zero gravity (0-G) and partial gravity.

Main Methods:

• 12 subjects underwent parabolic flights with 10 parabolas each at 0 g, 0.25 g, 0.50 g, and 0.75 g.
• Subjects received either 25 mg of oral promethazine or a placebo, in a counterbalanced design.
• Motion sickness was quantified using the Pensacola Motion Sickness Questionnaire, with scores collected preflight, postflight, and during flight.

Main Results:

• The placebo group reported significantly higher motion sickness scores postflight in 0-G compared to preflight.
• Promethazine reduced reported motion sickness instances from 51.8% of parabolas in the placebo group to 12.6% in the promethazine group.
• Four out of six subjects receiving promethazine reported no motion sickness, while all placebo subjects experienced symptoms.

Conclusions:

• Oral promethazine is effective in reducing space motion sickness symptoms in both 0-G and partial gravity conditions.
• Zero gravity (0-G) may induce more severe motion sickness than partial gravity, potentially due to greater sensory conflict.
• Further research is recommended to explore motion sickness across varying hypogravity levels.