Adverse events
As DMT activity centres on the immune system, infections are a common side effect, and people with MS are at significantly higher risk of infections requiring hospital treatment. Risk of serious infection also increases with age and number of years of exposure to the DMT.14
Respiratory or urinary tract infections are relatively common. Rarer but more serious infections can include sepsis or central nervous system infections such as progressive multifocal leukoencephalopathy, a viral infection targeting myelin in the brain.
One aspect of this is that people with MS are encouraged to take up offers of vaccination (such as seasonal or for travel) as catching an infection like flu may worsen symptoms or trigger a relapse. However, people who have been using certain DMTs or who have required steroids within the past three months for a relapse are advised to avoid live vaccines. Patients currently having a relapse may want to avoid any vaccines.15
Depending on the DMT, other significant side effects may include increased risk of hypertension, liver damage, eye damage, heart conditions, and certain cancers. Infusion procedures are also associated with their own risks.14