Hypersensitivity pneumonitis associated with co-proxamol (paracetamol plus dextropropoxyphene) therapy

A 61-year-old man developed hypersensitivity pneumonitis and skin rash in close association with taking co-proxamol. These problems occurred in spite of being treated with prednisolone 40 mg daily (20 mg daily at the time of presentation) for assumed cranial arteritis. A therapeutic challenge with paracetamol was negative and the patient continues to take this drug. It seems likely that this patient's rash and hypersensitivity pneumonitis was caused by dextropropoxyphene. Dextropropoxyphene has not been reported previously as a cause of hypersensitivity pneumonitis.