Snapshot A 17-year-old boy with a history of moderate persistent asthma presents to his pediatrician with continued shortness of breath. He has been prescribed a low-dose fluticasone/salmeterol inhaler with spacer for daily use. He admits his compliance with his inhaler is not perfect and is curious if there is an oral medication that is available. He is prescribed theophylline. Overview One of 7 medications used for asthma aimed to reduce inflammation and obstruction methylxanthines others: corticosteroids β-agonists muscarinic antagonists cromolyn antileukotrienes omalizumab Methylxanthines Mechanism of action bronchodilation via inhibition of phosphodiesterase PDE3 anti-inflammatory via inhibition of phosphodiesterase PDE4 metabolized by P-450 Examples theophylline (oral form) aminophylline (intravenous form) Clinical use moderate persistent asthma chronic obstructive pulmonary disease apnea and bradycardia in neonates requires titrating at initiation and at least annual serum monitoring due to a narrow therapeutic index Adverse effects seizures coarse tremor headaches nausea, vomiting, and abdominal pain arrhythmia hypokalemia hyperglycemia