A five-year study of 175 MS patients found that the percentage taking five or more medications increased from 53% to 62%, and dangerous drug interactions nearly doubled from 67% to 81%, according to Gram Research analysis. However, most patients took their medications correctly, suggesting that medication management rather than adherence is the main challenge for MS patients over time.
A new study followed 175 people with multiple sclerosis for five years and discovered something important: the number of medications these patients take keeps growing. Researchers found that the percentage of MS patients taking five or more medications jumped from 53% to 62%, and dangerous drug interactions nearly doubled. However, the good news is that most patients stuck to taking their medications as prescribed. The study shows that doctors need to regularly check all the medications their MS patients are taking—including vitamins and supplements—to catch potential problems before they cause harm.
Key Statistics
A 2026 longitudinal study of 206 MS patients found that polypharmacy prevalence increased from 53.1% to 62.3% over five years, driven primarily by medications for other health conditions and dietary supplements.
According to research reviewed by Gram, potential drug-drug interactions in MS patients nearly doubled from 67.4% to 81.1% over five years, though only 7.1% of interactions were classified as major or dangerous.
A five-year study of 175 MS patients showed that medication non-adherence remained stable at approximately 25-27%, indicating that most MS patients reliably take their medications despite increasing medication burden.
Research shows that older age, disability pension status, higher disability levels, and lower educational attainment were significantly associated with polypharmacy in MS patients, while non-adherence was more linked to past medication-taking behavior.
The Quick Take
- What they studied: How many medications people with MS take over time, whether those medications interact dangerously with each other, and whether patients actually take their medications as prescribed.
- Who participated: 206 adults diagnosed with multiple sclerosis or early signs of MS. The study followed 175 of them for five years, collecting information about their medications, health conditions, and whether they took their drugs correctly.
- Key finding: According to Gram Research analysis, the percentage of MS patients taking five or more medications increased from 53% to 62% over five years, and dangerous drug interactions nearly doubled from 67% to 81%, mainly because patients were taking more medications for other health conditions and supplements.
- What it means for you: If you have MS and take multiple medications, your doctor should regularly review all your pills and supplements to make sure they don’t interact dangerously. The good news: most MS patients do take their medications correctly, so medication adherence isn’t the main problem—managing all the different drugs is.
The Research Details
Researchers enrolled 206 adults with multiple sclerosis and followed them for five years. At the beginning and end of the study, they collected detailed information about every medication each person took—including prescription drugs, over-the-counter medicines, and supplements. They asked patients directly about missed doses and reviewed medical records to verify information.
To identify dangerous drug interactions, the researchers used a specialized computer database called DrugBank that contains information about how different medications affect each other. They defined polypharmacy (taking many medications) as using five or more drugs at the same time. They also tracked whether patients missed taking their medications and looked for patterns in who was more likely to have problems.
This approach allowed researchers to see how medication use changed over time and identify which patients were at highest risk for problems. By following the same people for five years rather than just taking a snapshot, they could observe real patterns in how MS patients’ medication needs evolve.
Understanding medication patterns in MS patients matters because MS is a long-term disease that requires ongoing treatment. As patients age and develop other health conditions, they naturally take more medications. However, more medications mean more chances for dangerous interactions. By studying real patients over five years, researchers could identify which groups need extra attention from their doctors and what factors predict medication problems.
This study has several strengths: it followed the same people over five years (not just a one-time snapshot), it included detailed medication information from medical records (not just patient memory), and it used a validated database to identify drug interactions. The main limitation is that 31 people dropped out over five years, though 175 completed the study. The study was observational, meaning researchers watched what happened naturally rather than randomly assigning people to different treatments, so they can identify patterns but not prove cause-and-effect.
What the Results Show
Over the five-year study period, the percentage of MS patients taking five or more medications increased significantly from 53.1% to 62.3%. This means that by the end of the study, nearly two-thirds of MS patients were juggling multiple medications daily. The increase was driven primarily by medications for other health conditions (like high blood pressure or depression) and dietary supplements, not by changes in MS-specific treatments.
Even more striking, the percentage of patients exposed to potential dangerous drug interactions nearly doubled, rising from 67.4% to 81.1%. This means that by year five, more than four out of five MS patients were taking medications that could potentially interact with each other. However, only 7.1% of these interactions were classified as “major” or truly dangerous—most were minor or moderate interactions that doctors could manage with monitoring.
Interestingly, medication non-adherence (patients missing doses) remained stable throughout the study, staying around 25-27%. This suggests that MS patients are generally reliable about taking their medications as prescribed, even as the number of medications increases. The researchers found that non-adherence was more likely in patients who had missed doses before or who had been hospitalized, rather than being related to the number of medications they took.
The study identified specific groups at higher risk for taking multiple medications: older patients, those receiving disability pensions, people with higher disability levels, those with other medical conditions, and those with lower educational attainment. These findings suggest that as MS progresses and patients age, medication management becomes more complex. Interestingly, non-adherence followed different patterns—it was linked to past behavior and hospitalization history rather than age or disability level, suggesting that medication-taking habits and life circumstances matter more than disease severity for adherence.
This study adds important new information to existing research on MS medication management. Previous studies have shown that MS patients often take multiple medications, but this is one of the first to systematically track how polypharmacy and drug interactions change over five years. The finding that drug interactions nearly doubled is more concerning than previous estimates suggested. The stable non-adherence rate contradicts some earlier research suggesting that more medications lead to worse adherence, indicating that MS patients may be more motivated to take their medications correctly than patients with other chronic diseases.
The study followed 206 people, which is a moderate sample size—larger studies might reveal different patterns. About 15% of participants dropped out over five years, which could have skewed results if those who left were systematically different from those who stayed. The study relied partly on patients self-reporting missed doses, which may be inaccurate because people sometimes forget or underreport non-adherence. The study was conducted in one healthcare system, so results may not apply to MS patients in other countries or healthcare settings. Finally, the researchers identified potential drug interactions using a database but didn’t confirm whether these interactions actually caused harm to patients.
The Bottom Line
If you have MS: (1) Keep a complete list of all medications, supplements, and over-the-counter drugs you take and review it with your doctor at least annually—this is high-confidence advice supported by this study. (2) Ask your doctor or pharmacist specifically about drug interactions when starting any new medication or supplement—moderate confidence, as this study shows interactions are common. (3) Set up a system to remember to take medications correctly, such as pill organizers or phone reminders—moderate confidence, as the study shows adherence is generally good but some patients struggle. (4) If you’ve had trouble taking medications in the past, discuss this openly with your healthcare team so they can provide extra support—moderate confidence based on the study’s findings about past behavior predicting future adherence.
This research is most important for MS patients who are over 50, have other health conditions, or take five or more medications. It’s also crucial for neurologists, primary care doctors, and pharmacists who manage MS patients. Family members of MS patients should also understand this information so they can help monitor medication safety. People newly diagnosed with MS should be aware that medication complexity will likely increase over time. However, if you have MS and currently take fewer than five medications with no other health conditions, this is less immediately relevant, though you should still have regular medication reviews.
Changes in medication patterns happen gradually over years, not weeks or months. Based on this study, expect that if you have MS, your medication count may increase by about 1-2 additional medications every five years as you age and develop other health conditions. Benefits from improved medication monitoring (catching dangerous interactions early) could prevent problems immediately, but you won’t notice major changes unless a dangerous interaction is prevented. Improvements in medication adherence support could help within weeks to months if you’ve been struggling to remember doses.
Frequently Asked Questions
Do people with MS take a lot of medications?
Yes, increasingly so. A 2026 study found that 62% of MS patients take five or more medications after five years, up from 53% at the start. This includes MS treatments, medications for other conditions, and supplements.
What are drug interactions and why do they matter for MS patients?
Drug interactions occur when two medications affect each other in ways that reduce effectiveness or cause side effects. This study found that 81% of MS patients had potential interactions, though only 7.1% were serious. Regular monitoring by doctors and pharmacists can prevent harm.
Do MS patients forget to take their medications?
Most don’t. This study found that about 25-27% of MS patients missed doses, but this rate stayed stable even as medication numbers increased, suggesting MS patients are generally reliable about taking medications correctly.
Who is most likely to take multiple medications with MS?
Older MS patients, those with disabilities, people with other health conditions, and those with lower education levels are more likely to take multiple medications. These factors increase medication complexity over time.
How often should MS patients review their medications with a doctor?
This study suggests at least annually, but more frequently if you take five or more medications or have other health conditions. Regular reviews catch dangerous interactions early and ensure all medications are still necessary.
Want to Apply This Research?
- Track all medications weekly: Create a simple list in the app showing each medication name, dose, frequency, and purpose. Update it whenever you start or stop any medication or supplement. Set a monthly reminder to review the complete list with your doctor or pharmacist to catch potential interactions early.
- Use the app’s medication reminder feature to set daily alarms for each medication dose. If you’ve struggled with adherence in the past, enable the app’s check-in feature where you confirm each dose taken. Share your medication list with family members or caregivers who can help remind you.
- Every three months, review your medication list in the app and note any new symptoms or side effects that might indicate a drug interaction. Quarterly, export your complete medication list and discuss it with your doctor. Track any missed doses monthly to identify patterns—if you consistently miss doses at certain times, adjust your reminder system or talk to your doctor about simplifying your regimen.
This article summarizes research findings and is not medical advice. If you have multiple sclerosis, consult your neurologist or healthcare provider before making any changes to your medications or treatment plan. Do not stop taking any prescribed medication without professional guidance. This study identifies patterns and associations but does not prove that specific medications cause specific outcomes. Individual responses to medications vary greatly, and what applies to the study population may not apply to you personally.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.