Sentence: Combination therapy with labetalol ( 400 mg/day ) and prazosin ( 6 mg/day ) was unsatisfactory , and the addition of long-acting nifedipine ( 40 mg/day ) produced a marked decrease in blood pressure .
Drug combination annotation:
[{'class': 'NEG', 'spans': ['labetalol', 'prazosin'], 'is_context_needed': False}, {'class': 'POS', 'spans': [0, 1, 2], 'is_context_needed': False}]