A 38-year-old woman with asthma and seasonal allergies is prescribed albuterol (salbutamol) inhaler for acute bronchospasm. She uses it 3–4 times daily for 2 weeks and reports tremor in her hands, palpitations, and mild anxiety. Her heart rate is 102 bpm at rest, and she has a fine tremor on finger extension. Spirometry shows FEV₁ of 78% predicted (baseline 85%). What is the most appropriate next step in management?