Sentence: Eighty-three patients were in the control group who have performed a surgical intervention with pre-operative 120-hour antibiotic prophylaxis by Claforan ( cefotaxime ) combining with Metrogel ( metronidazole ) .
Drug combination annotation:
[{'class': 'POS', 'spans': ['cefotaxime', 'metronidazole'], 'is_context_needed': True}]