Saridon induced methaemoglobinemia: a rare cause of cyanosis in a young adult male

Saridon (Propyphenazone 150mg, Paracetamol 250 mg & Caffeine 50mg) is a very commonly prescribed analgesic and also a easily available over the counter pain killer. Methemoglobinemia is a known but rarely reported complication of saridon, probably because the drug has been banned in many countries. We describe our experience of 25yr old male patient with cyanosis. The key points instrumental in suspecting methemoglobinemia in our case were history of drug overdose, lethargy, cyanosis and the presence of saturation gap (low SpO2 on pulse oximeter & normal/high arterial partial pressure of oxygen (PaO2) in Arterial Blood Gas analysis). Prompt administration of methylene blue and improvement of cyanosis helped us in confirming drug induced methemoglobinemia much before the lab results of methemoglobin levels arrived, thus establishing our diagnosis.