Endari (L-glutamine) is a brand-name oral powder that’s prescribed to reduce complications of sickle cell disease in adults and some children. As with other drugs, Endari can cause side effects, such as nausea and headache.

Endari can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Endari in clinical trials:

* For more information about this side effect, see “Side effect specifics” below.

Mild side effects can occur with Endari use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Endari’s prescribing information.

Mild side effects that have been reported with Endari include:

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you develop a side effect while taking Endari and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics” below.

† An allergic reaction is possible after using Endari. However, this side effect wasn’t reported in clinical trials. To learn more, see the “Side effect specifics” section below.

Endari may cause serious side effects, but they aren’t common. Like all drugs, Endari can cause a severe allergic reaction.*

If you develop serious side effects while taking Endari, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number. For more information, you can refer to Endari’s prescribing information.

* An allergic reaction is possible after using Endari. However, this side effect wasn’t reported in clinical trials. To learn more, see the “Side effect specifics” section below.

Endari may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

How do side effects of Endari compare with those seen with hydroxyurea?

Endari and hydroxyurea can cause some similar side effects, but there are also some differences. For example, both Endari and hydroxyurea can cause mild side effects such as nausea, cough, headache, and constipation. However, hydroxyurea can also cause loss of appetite, hair loss, and sleepiness.

Severe side effects with Endari are rare. Hydroxyurea may cause some serious side effects that Endari doesn’t. These may include pulmonary fibrosis (scarring of the lung tissue) and bone marrow suppression (reduced activity of the bone marrow resulting in lower red blood cells, white blood cells, and platelets).

If you have additional questions about side effects of Endari or hyroxyurea, talk with your doctor or pharmacist.

Can Endari cause long-term side effects?

It isn’t likely. Long-term side effects weren’t reported in clinical trials of Endari. Most of the drug’s side effects are expected to be temporary. They’ll likely go away shortly after you start or stop treatment with the drug. However, the length of time Endari’s side effects last will vary among individuals.

If you have questions about long-term side effects with Endari, talk with your doctor or pharmacist.

Learn more about some of the side effects that Endari may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Endari.

Back pain

Body pain was commonly reported in people who used Endari in clinical trials. It’s important to note that pain, including back pain, is also a common symptom of sickle cell disease (the condition Endari is prescribed to treat).

What you can do

Talk with your doctor if you experience back pain while taking Endari. Your doctor can help determine whether your symptoms could be due to sickle cell disease, Endari, or another factor.

This will also affect what your doctor recommends to treat your symptoms. For example, they may suggest exploring other treatments for sickle cell disease besides Endari if it seems the medication is causing your symptoms.

Nausea

Nausea was commonly reported by people who took Endari in clinical trials. Nausea may go away after a couple days or weeks as your body adjusts to the medication.

Keep in mind that sickle cell disease (the condition Endari is prescribed to treat) can frequently cause nausea as a symptom. There are also many other possible causes of nausea. This can make it difficult to tell whether your nausea symptoms are due to Endari, sickle cell disease, or another factor.

What you can do

If you have nausea during treatment with Endari, the best thing to do is stay hydrated. Try to take small sips of cold water or other clear fluids. An empty stomach can make nausea worse, so try not to skip meals. Try eating small amounts of food more often. It may also be best to avoid fatty, spicy, or very sweet foods, as these can make nausea worse.

Talk with your doctor if you have nausea that doesn’t go away or becomes bothersome. They may recommend additional ways to help prevent or reduce nausea.

Allergic reaction

As with most drugs, Endari can cause an allergic reaction in some people. However, this side effect wasn’t reported in clinical trials.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Endari. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Be sure to talk with your doctor about your health history before you take Endari. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. These include:

Allergic reaction: If you’ve had an allergic reaction to Endari or any of its ingredients, your doctor will likely not prescribe Endari. Ask your doctor what other medications may be better options for you.

Pregnancy or breastfeeding: It’s not known if Endari is safe to take if you’re pregnant or breastfeeding your child. Please talk with your doctor before taking Endari if you’re pregnant, planning to become pregnant, or breastfeeding.

Alcohol consumption: If you drink alcohol, talk with your doctor about how much alcohol is safe for you to drink. Alcohol can cause dehydration, which may lead to a sickle cell crisis (an episode of severe pain).

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.