What is Methotrexate?
Methotrexate is a disease-modifying antirheumatic drug (DMARD) widely used to treat various conditions, including rheumatoid arthritis (RA), severe psoriasis, and certain types of cancer [1.8.3, 1.10.2]. It is considered a first-line treatment for RA by both the American College of Rheumatology and the European League Against Rheumatism [1.7.3]. The medication works by interfering with the metabolism of folic acid, an essential B vitamin, which helps to slow the growth of rapidly dividing cells, like cancer cells and immune cells involved in autoimmune inflammation [1.10.3]. For conditions like RA, it's also believed to work by causing cells to release adenosine, a molecule that blocks inflammatory chemicals [1.6.4].
Can Methotrexate Cause Dizziness?
Yes, dizziness is a reported neurological side effect of methotrexate [1.2.4, 1.3.4]. While often considered infrequent, some studies indicate it's more common than previously thought. One study of over 1,000 RA patients found that 12% reported dizziness in the first year of treatment [1.3.1]. These symptoms often occur soon after taking the weekly dose and may improve on their own as the body adjusts to the medication [1.3.2].
This side effect is part of a range of central nervous system (CNS) toxicities associated with low-dose methotrexate, which can also include headaches, drowsiness, and difficulty concentrating [1.5.1, 1.5.3]. Research suggests that older patients and those with even mild kidney insufficiency may be more susceptible to these CNS effects [1.2.2].
Why Does It Happen?
The exact mechanism for how methotrexate causes dizziness and other CNS effects isn't fully understood, but it's believed to be related to its impact on the central nervous system [1.5.1]. The medication can cross the blood-brain barrier and may cause symptoms ranging from mild cognitive impairment and headaches to more severe issues like confusion or seizures in rare cases, particularly with high doses [1.5.2, 1.5.5]. For the common low-dose weekly regimen, symptoms like dizziness are typically less severe [1.5.2].
Managing Dizziness and Other Common Side Effects
Experiencing side effects can be concerning, but many are manageable. If you feel dizzy or drowsy after taking methotrexate, it is advised not to drive or operate heavy machinery until you know how the medication affects you [1.2.5].
Here are several strategies often recommended by healthcare providers:
- Folic Acid Supplementation: Taking a folic acid supplement is a standard recommendation for patients on methotrexate. It helps protect healthy cells and can reduce the incidence of many side effects, including gastrointestinal issues and mouth sores, by as much as 79% [1.4.2, 1.10.3]. Your doctor will prescribe the correct dosage and schedule, which is often taken the day after your methotrexate dose [1.4.5].
- Dose Timing and Splitting: Some patients find that taking their dose in the evening helps them sleep through immediate side effects like fatigue or a "methotrexate fog" [1.7.4]. For oral pills, splitting the dose—taking half in the morning and half 12 hours later—may ease gastrointestinal distress [1.4.2]. Always consult your doctor before changing how you take your medication.
- Stay Hydrated: Proper hydration is crucial, as dehydration can worsen side effects and strain your kidneys, which are responsible for clearing methotrexate from your body [1.4.4].
- Lifestyle Adjustments: Avoid or limit alcohol, as it can increase the risk of liver toxicity when combined with methotrexate [1.4.1, 1.6.4]. Also, protect your skin from the sun, as methotrexate can cause photosensitivity, making you more prone to sunburn [1.4.3, 1.6.2].
Comparison of Common DMARD Side Effects
All medications have potential side effects. It's helpful to understand how methotrexate compares to other common DMARDs.
| Feature/Side Effect | Methotrexate | Hydroxychloroquine (Plaquenil) |
|---|---|---|
| Common Side Effects | Nausea, fatigue, mouth sores, dizziness, hair thinning [1.3.1, 1.6.4, 1.7.4]. | Nausea, diarrhea, stomach cramps [1.11.1]. |
| Serious Risks | Liver damage, lung inflammation, low blood cell counts [1.4.2, 1.6.5, 1.7.2]. | Retinal (eye) damage, heart rhythm problems [1.11.1]. |
| Monitoring | Regular blood tests for liver function, kidney function, and blood counts are essential [1.6.2]. | Regular eye exams are required to monitor for retinal toxicity [1.11.1]. |
| Use in Pregnancy | Not safe for use during pregnancy [1.11.1]. | May be considered an option during pregnancy for certain conditions [1.11.1]. |
When to Contact a Doctor
You should report any side effects to your doctor. While mild dizziness may resolve on its own, it's important to seek medical advice promptly if dizziness is severe, persistent, or accompanied by other concerning symptoms [1.9.3].
Call your doctor within 24 hours if you experience:
- Marked fatigue or dizziness [1.6.2]
- Difficulty breathing [1.6.2]
- Yellowing of the skin or eyes (a sign of liver problems) [1.6.5]
- Fever, chills, or sore throat (signs of infection) [1.6.5]
- Unusual bruising or bleeding [1.6.1]
Seek immediate medical attention (call 999 or go to A&E) if you experience signs of a severe allergic reaction, such as:
- Sudden confusion or severe dizziness [1.6.5]
- Swelling of the lips, mouth, or throat [1.6.5]
- Difficulty breathing or swallowing [1.6.5]
- Seizures or loss of consciousness [1.2.4]
Conclusion
Dizziness is a known neurological side effect of methotrexate, affecting a notable percentage of users, particularly early in treatment [1.3.1, 1.5.3]. It is often part of a cluster of CNS symptoms that includes headache and fatigue, which may lessen over time [1.3.2]. Management strategies like taking folic acid, adjusting dose timing, and avoiding alcohol can significantly mitigate this and other side effects [1.4.2, 1.4.1]. Regular monitoring and open communication with your healthcare provider are critical to safely and effectively using methotrexate for managing your condition. Always report new or worsening side effects to your doctor to ensure the best course of action.
For more information from a trusted source, you can visit the NHS page on Methotrexate.
