A 36-year-old female has a 7-year history of pollen allergy. Over the last 2 years in August and September (during ragweed flowering), the patient has had 2-3 asthma attacks that could be treated with one dose of salbutamol. Objectively: body temperature - 36,5°C, respiratory rate - 18/min, Ps - 78/min, AP - 115/70 mm Hg. There is vesicular breathing above the lungs. Cardiac sounds are sonorous, of regular rhythm. What drug would be most effective to prevent asthma attacks during the critical season for the patient?