The drug has an established safety profile. The patient population that is most susceptible to side effects are not given the drug based off a simple EKG.
Also, in reference to the autoimmune disorders, it is part of a combo of drugs that are designed to “modify” the symptoms, but are not actually testing or curing the problem. The most common symptoms treated are skin and joint problem. I imagine if the medication has a potential benefit in saving lives, the supply will be quickly moved from those needing it to prevent skin lesions.
From WebMD
“This
medication is also used, usually with other
medications, to treat certain auto-immune diseases (
lupus,
rheumatoid arthritis) when other medications have not worked or cannot be used. It belongs to a class of medications known as disease-modifying antirheumatic drugs (DMARDs). It can reduce
skin problems in
lupus and prevent swelling/pain in
arthritis, though it is not known exactly how the drug works.”