Sentence: The pharmacodynamic effects of single doses of trazodone ( 100 mg ) , amitriptyline ( 50 mg ) or placebo either alone or with ethanol ( 0.5 ml/kg ) were investigated in 6 healthy volunteers in a double-blind crossover study .
Drug combination annotation:
[{'class': 'COMB', 'spans': ['trazodone', 'ethanol'], 'is_context_needed': True}, {'class': 'COMB', 'spans': [1, 2], 'is_context_needed': True}, {'class': 'COMB', 'spans': [2, 3], 'is_context_needed': True}]