Distinguish the toxicity of various drugs used to treat rheumatoid arthritis.

Explanation:

Listed below are some key points

Hydroxychloroquine: Retinal damage-thus patient needs to have an eye check every 6 months

Gold salts: Marrow suppression but this is preceded by  EOSINOPHILIA therefore check CBC every month

Sulfasalazine: decreased sense of taste(hypogeusia).

Methotrexate: Liver toxicity therefore monitor LFTs every 4-6 months. It also causes marrow toxicity therefore check CBC every month. It also can cause pulmonary infiltrates therefore a baseline CXR should be done but repeat only if there is a pulmonary problem.

Azathioprine: Gradually falling blood count therefore check CBC every month. This side effect is reversible on cessation of therapy.