Azathioprine for Myasthenia Gravis
Last updated: June 2023
Editor's Note: Azathioprine is used off-label to treat myasthenia gravis. Talk to your doctor about the risks and benefits of this treatment.
Azathioprine, also known as Imuran, is a drug used in myasthenia gravis (MG). Azathioprine is used for many conditions that affect the immune system, including rheumatoid arthritis and post-organ transplantation.1
Azathioprine is used off-label for MG, meaning that it is used for a different condition than it was originally intended for. The following will outline what to expect when starting your treatment with azathioprine.
How does it work?
Azathioprine works by suppressing the immune system. Normally, a strong immune system is desirable. However, for people with autoimmune conditions, the goal is to suppress the immune system because it is overactive. Azathioprine is not a steroid.1
How is it taken?
Azathioprine may be prescribed as an intravenous formulation or a tablet. However, the most common formulation is the tablet. It is typically used if someone continues to have symptoms while on pyridostigmine.1
For people with MG, the exact dose is dependent on weight. Your doctor will confirm your target dose and individualize it based on your other health factors.
Similar to other drugs used to treat MG, it takes time before a response to azathioprine can be seen. The maximum effect can take 1-2 years.2 Many studies observing use in people with MG show that it can help improve symptoms in 70-90 percent of people with MG.3
Possible side effects
The most common side effect of azathioprine is nausea and vomiting.1 This can be minimized by taking the medication with food. If you are experiencing side effects, speak to your doctor.
Like many of the MG drugs, azathioprine comes with warnings prior to use. For example, long-term use of this drug may increase the risk of cancer, including skin cancer. For that reason, it is recommended to practice sun safety and get regular skin checks.3
Because this drug increases the risk of infections, getting vaccinated for certain infectious conditions can help prevent sickness. Azathioprine should also not be used in pregnancy.4
Potential drug interactions
Azathioprine has the potential for severe drug interactions. For example, febuxostat and allopurinol. These medications are used to treat gout. The combination should be avoided whenever possible, as it has the potential to be deadly. Always ask your physician and pharmacist if you take any over-the-counter medications.4
Of note, azathioprine does not interact with the COVID-19 vaccine. However, because azathioprine suppresses the immune system, it may reduce the response to the COVID-19 vaccine.4
Do you take azathioprine to treat your myasthenia gravis? Share your experience with this drug below!
How often do you experience MG exacerbations/flares?