How To Know When a Medication Change Is Necessary With MS

When referring to medications for MS, we typically think about disease modifying therapies (DMTs). These are the medications that affect the biological processes that cause MS relapses and demyelinating lesions on MRI, and thus change the natural history of the disease. DMTs target the immune system to stop relapses and the development of new demyelinating lesions on MRI, and thus reduce disability outcomes. Other medications are used to help with symptoms such as spasticity, fatigue, urinary control, and walking ability. Symptomatic medications do not change the natural history of the disease, but can improve day-to-day function.  

For either type of medication, we always want to periodically check to see if the medication is working well (called efficacy), without causing any problems from either a safety concern or side effect concern (called tolerability).

Disease Modifying Therapies – Efficacy

Again, the role of DMTs is to stop clinical relapses and development of new demyelinating lesions on MRI. They are preventative, and typically do not improve symptoms. Therefore, determining if the DMT is working is typically due to making sure you are not having clinical relapses or new MS lesions on MRI. Relapses can be tricky, as sometimes people can feel worse. This is not due to a new immune attack, but rather worsening of symptoms due to other causes such as infection, heat, dehydration, or side effects of medications. This would be considered a pseudo-relapse. It is critical that your MS provider distinguishes between true relapses and pseudo-relapses, and MRI as well as other tests such as lab work can help determine if your symptoms are worsening due to new inflammation vs another cause. Like relapses, it is also important to make sure new lesions on MRI are due to MS, rather than other disease processes. For example, white matter lesions also occur due to migraines or vascular disease such as hypertension. White matter lesions also increase with age (occurs in 5% of people aged 50 years, and 100% in people aged 90 years). If you are having true relapses or new MS lesions on MRI, this means your medications are not effectively controlling your disease, and thus changing medications is typically necessary. DMTs can take a few months to work, so we typically will not change medications if you have new disease activity after just starting DMTs, but if you have been on DMTs for several months and have not missed any doses, we would expect no relapses or new MS lesions on MRI. 

Disease Modifying Therapies – Safety and Tolerability

Safety concerns commonly include risk of serious infections, liver injury, impact on your heart or blood pressure, and rarely allergic reactions. Safety concerns can also increase if you develop other medical conditions, especially if additional medications are needed which can have drug-drug interactions. Depending on the safety issue, sometimes more frequent monitoring or adjusting your dose is adequate. However, if safety issues persist or worsen, then changing medications is essential.  

Tolerability concerns are side effects that can make you potentially uncomfortable, but are not necessarily harmful. For example, medications can make you more fatigued, or cause mild stomach irritation or headaches. For injectable medications, some people will have injection site reactions, but these are typically temporary and fairly easy to manage. Infusion medications can cause infusion reactions, which are also typically temporary and manageable with pre-medications and/or infusion rate changes. Different people can have variable side effect intensities, thus whether you should change medications based on tolerability is very individualized. Oftentimes, patients are worried about changing their DMTs, because “it is working” even though they are suffering from the side effects. We are very fortunate to have over 25 different DMTs, so that we can find a medication that does not reduce quality of life, while also controlling your disease. Do not be afraid to change a medication due to tolerability because we don’t want the treatment to be worse than the disease. There is a right DMT for everyone.  

Symptomatic Treatment

Similar to DMTs, we also need to make sure your symptomatic medications are working to control your symptoms. It is important to know why you are taking a certain medication (for example, for muscle tightness, depression, fatigue/impaired attention, urinary urgency/frequency), so we can monitor its effectiveness. A medication can stop working over time for many reasons, and those reasons require thorough evaluation to identify and manage appropriately. Symptomatic medications can often make other symptoms worse (anti-spasticity agents can make fatigue worse), and we are constantly balancing effectiveness and tolerability. Starting multiple medications at once can make it difficult to determine if a medication is working, and can make it difficult to determine which one is causing which side effects or safety issues. A simple approach is to make only one medication change/dosage adjustment at a time. You can help by letting your provider know which symptom is most bothersome and should be prioritized. As with DMTs, developing new medical conditions may require adjusting your symptomatic medications due to safety concerns or polypharmacy risks. 

Summary

Overall, it may seem complicated to decide whether to continue or change your DMTs and/or symptomatic therapy. However, your MS specialist is there to help. By keeping your provider informed of side effects and completing regular surveillance MRIs and lab tests, they can partner with you to determine which medication is right for you in controlling your MS and its symptoms.