Management of respiratory failure or rapidly progressive disease in adults with confirmed or presumed COP

COP: cryptogenic organizing pneumonia; IV: intravenous; IBW: ideal body weight; CXR: chest x-ray; PFTs: pulmonary function tests; BSA: body surface area.

* We use Pneumocystis jirovecii prophylaxis when the prednisone dose is expected to equal or exceed 20 mg for longer than four weeks. Trimethoprim-sulfamethoxazole (DS or SS) daily is the preferred regimen; atovaquone (1500 mg daily) is a reasonable alternative for those who cannot take trimethoprim/sulfamethoxazole.

¶ We prefer 500 mg/m² BSA in patients with age >70 years, creatinine clearance <40 mL/min, or otherwise at high risk for infections. In all patients, maximum single dose should not exceed 1200 mg.

Δ In this setting, we obtain thiopurine methyltransferase (TPMT) levels prior to azthioprine initiation. For patients with normal TPMT activity or for whom TPMT activity is unknown, we start azathioprine 50 mg orally once daily and increase the dose over two to three weeks to the target azathioprine dose of 1 to 2 mg/kg once daily (maximum 150 mg/day). The optimal dose in COP is unknown. Dose reduction is necessary in the setting of kidney disease. For patients with reduced TPMT activity, we prefer mycophenolate mofetil 1 to 1.5 g twice daily.

◊ In fulminant disease resistant to IV glucocorticoids, we obtain thiopurine methyltransferase (TPMT) levels at the time of steroid pulse or azathioprine initiation, and begin oral azathioprine therapy at the target dose of 1 to 2 mg/kg/day (maximum 150 mg/day). Dose reduction is necessary in the setting of kidney disease. Patients with reduced TPMT activity should be transitioned to an alternative agent to avoid toxicity (typically cyclophosphamide or mycophenolate mofetil, depending on disease course).