Drugs causing or worsening MG

Penicillamine: Rarely, about 1-2% of individuals treated long term with penicillamine develop MG and/or have low concentrations of antibodies to AChR. ^[1] Their MG is often mild and predominantly ocular MA, involves antibodies directed at AChR in about 80% of the cases, becomes evident usually 6–7 months (range one month to 8 years) after starting the drug), and goes into complete remission in 70% of the cases within 6–10 months after discontinuation of the drug. ^[2]

Immune checkpoint inhibitors: Immune checkpoint inhibitors promote certain types of autoimmune responses by blocking checkpoint pathways that inhibit these responses. The checkpoint inhibitors include pembrolizumab, nivolumab, ipilimumab, avelumab, atezolizumab, and durvalumab. From a total 5,898 patients who received these drugs, 52 developed new onset MG and 11 had a flare of their preexisting MG. The symptoms of MG developed with 6 days to 16 weeks (median time 4 weeks). Their MG was often sever with 29 patients developing respiratory failure that required mechanical ventilation. ^[3] Other studies have have also reported that these checkpoint inhibitors often produce life-threatening complications resulting in respiratory failure in 45% and fatality in 25–40% of patients. ^[2]