Kohl RL, Calkins DS, Sandoz GR.

Aviat Space Environ Med. 1991 May; 62: 465.

National Research Council/Space Biomedical Research Institute, NASA Johnson Space Center, Houston, Texas 77058.

INTRODUCTION. Doxepin (Sinequan (R)) may possess antimotion sickness properties due to its antihistaminergic, anticholinergic, and catecholaminergic actions. These properties are in common with proven antimotion sickness drugs like promethazine, scopolamine, and amphetamine. As a tricyclic antidepressant, doxepin is administered for 2 to 3 weeks to obtain therapeutic benefit believed related to changes in catecholamine receptors. METHODS. Severe nausea was induced by exposure to Coriolis stimulation using a rotating chair (ASEM 54:994). The efficacy of 70 mg/day of doxepin was tested on separate occasions, 4 hrs, 3 & 21 days after initiation of daily dosing. A double-blind, placebo-controlled, crossover design was used. Tests were conducted 4, 10, or 15 hrs post-dose. RESULTS. Coriolis Sickness Susceptibility Index scores increased 202 +/- 71, 150 +/- 40, and 190 +/- 56% following 21, 3 days, and 4 hr loading with 70 mg. All subjects receiving doxepin did better than their corresponding placebo performance (p < 0.05). Cognitive function tests revealed sedation 4 hrs after dosing that was minimized with overnight dosing. CONCLUSIONS. Efficacy was high 4-15 hrs following the last oral dose. The long half-life of doxepin distinguishes its pharmacodynamic superiority to scopolamine plus amphetamine. Because acute and chronic loading of doxepin leads to comparable results, it is concluded doxepin efficacy is not related to chronic changes in catecholamine receptors. Efficacy is probably related to its potent antihistaminergic properties.

Publication Types:

• Meeting Abstracts

Keywords:

• Amphetamine
• Antidepressive Agents, Tricyclic
• Cholinergic Antagonists
• Coriolis Force
• Double-Blind Method
• Doxepin
• Placebos
• Promethazine
• Scopolamine
• NASA Center JSC
• NASA Discipline Neuroscience
• NASA Discipline Number 16-10
• NASA Program Space Physiology and Countermeasures

Other ID:

• 95607889

UI: 102212717

From Meeting Abstracts