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July 7, 2023

10 Mesalamine Side Effects to Look For

Learn about what mesalamine is used for, its common side effects, and other alternatives to this medication.
Medically Reviewed
Written by
Chanel Dubofsky
Medically Reviewed by
Dr. Robert Floyd

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Mesalamine (5-aminosalicylic acid, sold under names such as Lialda and Apriso), is an anti-inflammatory drug that's been used for more than 30 years in the treatment of ulcerative colitis (UC). Mesalamine can bring on or maintain remission — periods without symptoms — in people with mild or moderate UC. Mesalamine has known side effects you should know about if you're considering trying it. In this article, we'll take a look at mesalamine side effects, other available treatments if mesalamine doesn’t work for you, and diet and lifestyle changes that may help reduce UC symptoms, with or without mesalamine. (Source, Source

What Does Mesalamine Do? 

Mesalamine belongs to a group of compounds known as aminosalicylates. Mesalamine decreases inflammation in the digestive tract but doesn't suppress your immune system. It reduces UC symptoms such as: 

  • diarrhea, often with blood or pus
  • passing small amounts of blood in the stool (rectal bleeding) 
  • abdominal pain and cramping
  • rectal pain
  • an urge to defecate with the inability to do so 
  • weight loss
  • fatigue
  • fever

Mesalamine can also be used to treat mild symptoms of Crohn's disease (usually after surgery) but is usually administered alongside other drugs. (Source, Source)

what is mesalamine

Before You Take Mesalamine

Some formulations of mesalamine should be avoided if you have certain pre-existing health conditions. If you're considering mesalamine, be sure to let your provider know if you have any of the following: 

  • a stomach or bowel ulcer 
  • kidney or liver disease 
  • heart disease 
  • a blockage in your urinary tract 
  • any allergies, in particular to sulfasalazine, aminosalicylates, or salicylates 
  • a skin condition such as eczema
  • phenylketonuria, a genetic condition in which phenylalanine, an amino acid, builds up in the blood and causes damage to the nervous system
  • if you're pregnant, planning to become pregnant, or breastfeeding. It's not known if mesalamine has a negative effect on pregnancy, but active ulcerative colitis and Crohn's have been associated with adverse outcomes. If you're breastfeeding, your infant should be monitored for diarrhea while you take mesalamine. 

(Source, Source, Source, Source, Source

Side Effects of Mesalamine 

Unlike other drugs that treat autoimmune conditions, mesalamine isn't an immunosuppressant, isn’t associated with an increased risk of infection or cancer, and is usually well tolerated. 

When adverse reactions do occur, they are usually due to the active component (5-aminosalicylic acid, or 5-ASA). However, you may also experience intolerance to other ingredients such as the sulfa drug sulfapyridine, which may be combined with mesalamine to form sulfasalazine. Mesalamine formulations without sulfapyridine are likely to cause fewer side effects. (Source, Source)

The symptoms and conditions related to mesalamine intolerance are generally dose-related and usually resolve if the dose is lowered, but your provider may also decide that mesalamine isn't right for you. That said, there are some effects you should be aware of, and you should notify your provider if they become severe.

10 side effects of mesalamine

Common Side Effects 

The following side effects are common and usually mild, but if you experience them as severe you should contact your provider:

  • nausea 
  • headache
  • back pain 
  • heartburn
  • burping or gas
  • constipation 
  • dizziness 
  • decreased appetite 
  • sweating 
  • muscle or joint pain 


Mesalamine-Induced Acute Intolerance Syndrome 

The active component in mesalamine is 5-aminosalicylic acid, also called 5-ASA. Although 90% of those prescribed mesalamine for treatment of ulcerative colitis tolerate the medicine well, 3% of patients during clinical trials demonstrated mesalamine-induced acute intolerance syndrome, a clinical diagnosis indicated by the following symptoms: 

  • skin that's itchy, peeling, or blistering 
  • rash or hives
  • fever or flu-like symptoms
  • swelling of the eyes, face, lips, tongue, mouth, throat, or glands 
  • shortness of breath or difficulty breathing or swallowing
  • new cough, or one that worsens 
  • chest, back, or side pain, or pain in the upper right part of the abdomen 
  • black, tarry, or pale stools
  • bloody vomit, or vomit that looks like coffee grounds
  • urination that's painful, difficult, or bloody, or pink or red colored urine
  • yellowing of the skin or eyes

When mesalamine intolerance is severe, it can cause: 

  • hepatotoxicity (liver injury) 
  • pancreatitis (inflammation of the pancreas) 
  • interstitial nephritis (a condition that interferes with kidney function) 
  • pneumonitis (inflammation of the lungs)
  • pericarditis (inflammation of the tissues around the heart) 

(Source, Source

midriff of person with their hands on their hips

Mesalamine-Induced Symptom Exacerbation

In rare cases, mesalamine has actually caused symptoms of UC (including fever, abdominal pain, and bloody diarrhea) to worsen. This usually happens 2 to 3 weeks after starting mesalamine and may be confused with mesalamine intolerance. With exacerbation, though, symptoms of UC first improve and then later become aggravated.

One study of 8 patients with UC aggravated by 5-ASA revealed that right-sided colitis, a condition in which the right side of the colon is inflamed, is characteristic of mesalamine-induced symptom exacerbation. Why this happens is not well understood, and more research is needed. (Source, Source)

Managing Mesalamine Side Effects 

Knowing how to handle the common side effects of mesalamine is an important part of not only using the drug, but deciding if it's right for you. Some ways to manage them include: 

  • If you have a skin condition such as eczema, you may be more at risk for photosensitivity and may burn very easily. Be sure to use a broad spectrum sunscreen (one that protects you from both UVA and UVB rays) and cover up when you're outside. You should also avoid tanning beds and sunlamps. 
  • It's important to stay hydrated when you're taking mesalamine, particularly if you're taking Apriso (a long-acting form of mesalamine), which can lead to an increased risk of kidney stones. 

(Source, Source)

Mesalamine and Drug Interactions 

Mesalamine may react with a number of other drugs, and some reactions may be serious. Be sure your health care provider knows about all prescriptions you're taking, and any that you start taking while you’re on mesalamine. Known drug interactions include: 

  • Antacids and medications that treat gastric ulcers, gastroesophageal reflux disease (GERD), and esophagitis may affect the amount of mesalamine your body absorbs. 
  • Taking mesalamine with immunosuppressants and chemotherapy agents such as azathioprine, 6-mercaptopurine, and thioguanine may lead to a reduction in white blood cells, increasing your risk of infection. 
  • Myelosuppressive agents such as mercaptopurine, used to treat hepatitis B and C, can increase the risk of bone marrow suppression when used with mesalamine. 
  • Heparin, which treats deep vein thrombosis, atrial fibrillation, and pulmonary embolisms, can increase bleeding and bruising when it interacts with mesalamine. 
  • When combined with mesalamine, NSAIDs such as aspirin and ibuprofen can cause a rapid deterioration in kidney function. 

(Source, Source, Source)

Alternatives to Mesalamine 

While mesalamine is a popular and generally well-tolerated drug for the treatment of UC, that doesn't mean it's going to be right for you, and it's not your only option. Here are some other routes to explore (and to let your provider know about): 

  • Andrographolide, an herb used in traditional Chinese medicine, has antioxidant, antibacterial, and anti-inflammatory properties and has been shown to relieve UC symptoms. Andrographolide comes with side effects of its own, and interacts negatively with some chemotherapy, anti-coagulation, and blood pressure lowering medications. 
  • Corticosteroids such as prednisone, prednisolone, methylprednisolone, and budesonide treat moderate to severe ulcerative colitis. Corticosteroids are synthetic analogs of cortisol, which is produced by the adrenal glands. After long-term use corticosteroids must be tapered off rather than stopped abruptly, because the adrenal glands will have slowed or even stopped producing their own cortisol. 
  • Immunosuppressants such as azathioprine, 6-mercaptopurine, cyclosporine, and tacrolimus target the immune system to prevent ongoing inflammation and can take several months to start working. Your provider may recommend immunosuppressants if aminosalicylates and corticosteroids aren't working for you. 
  • Balsalazide is a new drug that may be better tolerated than mesalamine. In one study, it was shown to achieve more rapid relief in symptoms, as well as improvement in the severity of UC. 
  • Targeted synthetic small molecules, such as tofacitinib and upadacitinib, break down in the gastrointestinal tract, get absorbed into the bloodstream, and block inflammation in the intestine. 
  • Biologic/biosimilar therapies such as adalimumab, golimumab, and infliximab are made from naturally occuring materials. They're antibodies that target certain proteins in order to stop inflammation. 

(Source, Source, Source, Source, Source

person sitting

Easing Ulcerative Colitis Symptoms with Diet and Lifestyle 

Medication is important for the treatment of UC, and so is paying attention to diet and lifestyle. There's no specific diet for UC, but dietary modifications in addition to medication may help you control symptoms and prolong time between flare-ups. 

  • Use a journal to keep track of the foods that trigger your symptoms, so you can avoid them. 
  • Eat nutrient-dense meals. 
  • Avoid artificial sweeteners (aspartame, sucralose, saccharine), gluten, processed meat (lunch and deli bacon, hot dogs, sausages), industrial seed oils and palm oil. These foods are associated with increased inflammation. 
  • Add anti-inflammatory foods such as raspberries and squash to your diet.
  • Add foods with omega-3 fatty acids, such as salmon, mackerel, and sardines.
  • Minimize stress, which can trigger flare-ups by disturbing gut bacteria and aggravating your immune system. Your health care provider may be able to help you incorporate ways of coping with and reducing stress in your daily life. 

(Source, Source, Source

The Bottom Line

Most of mesalamine's side effects are temporary and well-tolerated, but some are more serious, as are some of its interactions with other medications. It’s possible to experience intolerance to the drug or worsening of UC symptoms while taking it. If it’s not the right choice for you, there are alternatives that may work better. 

Along with medication, maintaining a healthy diet and lifestyle can help manage UC symptoms. WellTheory can help you not only make changes to your diet for your autoimmune health, but also to find a community of others living with UC and other autoimmune conditions. Learn more about our personalized, whole-body approach.

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10 Mesalamine Side Effects to Look For

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