A 57-year-old male worker from a nearby insulation materials and dyes factory presents with confusion, dizziness, shortness of breath and cyanosis to his finger nails. You suspect methaemoglobinaemia.

1. List drugs/toxins from separate classes that cause methaemoglobinaemia. 4 marks

2. Apart from cyanosis and confusion, list other clinical and/or biochemical findings in methaemoglobinaemia. 5 marks

3. Complete the table by listing indications and adverse effects regarding antidote treatment with methylene blue in this patient. 4 marks

The patient has been given methylene blue with some improvement in his clinical state but wats to discharge himself without further management.

4. State the steps required for best practice in discharge against medical advice. 5 marks