Space motion sickness medications: interference with biomedical parameters

Area of Science:

• Space Medicine
• Aerospace Physiology
• Pharmacology

Background:

• Space motion sickness is a common issue for astronauts.
• Medications such as Scopolamine/Dexedrine are used to treat space motion sickness.
• Potential physiological effects of these medications on astronauts are not fully understood.

Purpose of the Study:

• To investigate if anti-motion sickness drugs administered to Skylab 3 and 4 crewmen interfered with biomedical evaluations.
• To analyze drug-related changes in physiological and hormonal parameters in healthy volunteers under simulated spaceflight conditions.

Main Methods:

• Healthy volunteers received Scopolamine/Dexedrine combinations mimicking space mission regimens.
• Analysis of 24-hour urine samples for hormones (cortisol, epinephrine, norepinephrine, ADH, aldosterone) and electrolytes.
• Monitoring of heart rate, body temperature, mood, and performance.

Main Results:

• Scopolamine/Dexedrine significantly increased mean heart rate and, in some subjects, rectal temperature.
• A phase shift in heart rate circadian rhythm was observed, indicating disturbed circadian synchrony.
• Elevated urinary cortisol and epinephrine, transient ADH increase, and decreased norepinephrine excretion were noted; aldosterone and urine volume remained unchanged.

Conclusions:

• While weightlessness likely causes increased aldosterone during early spaceflight, anti-motion sickness medication may contribute to elevated epinephrine and cortisol.
• The study highlights the potential for medication to confound biomedical data in space missions.
• Understanding drug effects is crucial for accurate astronaut health monitoring.