Question: what kind of drug is vyvanse classified as
[{'answer': 'prodrug', 'provenance': [{'wikipedia_id': '9687089', 'title': 'Lisdexamfetamine', 'start_paragraph_id': 17, 'start_character': 32, 'end_paragraph_id': 17, 'end_character': 39, 'bleu_score': 1.0, 'section': 'Section::::Pharmacology.:Mechanism of action.\n'}]}]