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HEALTH GUIDE / Prescription Drugs / Aminosalicylates



About aminosalicylates

Aminosalicylates are medications used to treat inflammatory bowel diseases (IBD), such as Crohn's disease (CD) and ulcerative colitis (UC). These drugs contain 5-aminosalicylic acid (5-ASA), an ingredient that helps control inflammation in the body.

CD and UC are chronic conditions that cause inflammation and sometimes ulcerations in the colon and other parts of the digestive tract. Active phases of the diseases include bouts of diarrhea, abdominal pain and cramping.

Research shows that many UC patients are not fully compliant with their medication regimen. However, when taken as prescribed, aminosalicylates are highly effective in treating the condition.

Although aminosalicylates are also used to treat CD, their role in treating this disorder is less clear. Though aminosalicylates can reduce mild to moderate gastrointestinal inflammation, they are less effective in treating severe outbreaks of inflammation.

Sulfasalazine was the first widely used aminosalicylate. It relies on a substance called sulfapyridine to carry the drug to the intestines, and sulfapyridine is closely associated with many side effects. Patients taking sulfasalazine may experience side effects such as fever, nausea, diarrhea, headache, rash, change in color of urine and skin to yellow-orange hue, reduced sperm count (in men) and, less commonly, pancreatitis, hepatitis, lung inflammation (pneumonitis), Stevens-Johnson syndrome (a skin reaction) and destruction of the red blood cells (hemolysis).

Today, newer types of aminosalicylates have been developed that do not rely on sulfapyridine to act as a carrier. Up to 90 percent of patients who experience side effects related to sulfapyridine can safely take these newer aminosalicylates, according to the Crohn’s & Colitis Foundation of America (CCFA).

In addition, patients who do not respond well to some forms of aminosalicylates may benefit from trying another type. For example, a large percentage of patients who do not respond well to the aminosalicylate mesalamine often benefit from taking a newer aminosalicylate called balsalazide, which is converted to mesalamine and 5-ASA in the colon.


Types and differences of aminosalicylates

Aminosalicylates are available in four different varieties:

Generic NameBrand Name









Aminosalicylates are also available in various formulations. The type of formulation used will depend upon the location of inflammation in the digestive tract.

Mesalalmine preparations such as Asacol and Pentasa are modified to release the medication to specific locations with in the gastrointestinal tract. Asacol is a delayed release formulation which generally releases mesalamine only in the colon. Therefore it is only useful in patients with colitis, and not those with disease involving the small bowel. Pentasa, on the other hand, is a prolonged release formulation, which delivers mesalamine throughout the colon, from the duodenum to the rectum. The most common way to take aminosalicylates is via a conventional oral preparation of tablets or capsules.

Other methods of delivering these drugs include:

  • Enemas. Used for left-sided colitis only. Mesalamine is the drug used for this purpose, and it is applied in the colon up to the splenic flexure, a bend that appears near the spleen. About 80 percent of patients who use these enemas once daily report beneficial effects, according to the Crohn's & Colitis Foundation of America (CCFA).
  • Suppositories. These are solid medications that are inserted into a body cavity other than the mouth (e.g., rectum) before melting and passing into the bloodstream. They are used for ulcerative proctitis, a condition in which inflammation is limited to the rectum. Mesalamine is also used in this treatment and is applied from the rectum up to the sigmoid colon. The drug is usually administered twice daily, and the effectiveness of suppositories may be increased by combining this therapy with mesalamine pills.

Conditions of concern

Patients may not be good candidates for taking aminosalicylates if they have been diagnosed with kidney or liver disease.

In addition, sulfasalazine should not be used in patients with intestinal or urinary tract obstructions. The presence of certain conditions requires patients to use caution when taking sulfasalazine. These conditions include severe allergies, asthma and various blood disorders.

Side effects

Potential side effects of aminosalicylates

Common side effects associated with aminosalicylates include nausea, abdominal pain, headache, dizziness and fatigue. In rare cases, these drugs can cause inflammation of the liver (hepatitis) or inflammation of the pancreas (pancreatitis).

Symptoms such as fatigue, abdominal pain and dizziness are related to the dosage level of the patient. Reducing the dosage level may cause a corresponding decrease in the incidence of side effects. However, the incidence of conditions such as hepatitis and pancreatitis is unrelated to dosage levels.

Sulfasalazine is more likely than other aminosalicylates to trigger side effects. Most side effects are associated with the ingredient sulfapyridine, which carries the anti-inflammatory ingredient 5-aminosalicylic acid (5-ASA) to the intestines. Sulfasalazine use is closely associated with many side effects such as fever, nausea, diarrhea, headache, rash, change in color of urine and skin to yellow-orange hue, reduced sperm count (in men) and, less commonly, pancreatitis, hepatitis, lung inflammation (pneumonitis), Stevens-Johnson syndrome ( a skin reaction) and destruction of the red blood cells (hemolysis). The other aminosalicylates have different carriers that are less likely to cause side effects.


Drug or other interactions

Patients should consult their physician before taking any additional prescriptions, over-the-counter medications, nutritional supplements or herbal medications. Patients should not take aminosalicylates if they are allergic or otherwise sensitive to salicylates (such as aspirin).

Patients also should not use sulfasalazine if they are allergic or otherwise sensitive to drugs containing sulfur, such as thiazides (blood pressure drugs), furosemide (drug that reduces swelling and water retention) or sulfonylureas (antidiabetic drugs). Antacids may increase the body’s ability to absorb sulfasalazine, raising the risk of toxicity. Use of sulfasalazine may also reduce gastrointestinal absorption of drugs such as digoxin (heart drug) and folic acid (used to treat deficiency of the B vitamin).

Oral antibiotics may interfere with the release of aminosalicylates such as balsalazide in the intestines. Aminosalicylates may also increase the effects of anticoagulants, resulting in excess bleeding.


Lifestyle considerations

Patients who take the aminosalicylate sulfasalazine may experience increased sensitivity to the sun (photosensitivity). Patients should consult their physician about precautions they can take to avoid sunburn.

Patients who take sulfasalazine may also find that it causes permanent yellow stains on soft contact lenses.

How to use

Pregnancy use issues

Women who are pregnant, thinking of becoming pregnant or breastfeeding should not take aminosalicylates without first consulting a physician. The use of sulfasalazine is not recommended for women who are pregnant or breastfeeding, whereas use of mesalamine appears to be safe during pregnancy. Aminosalicylates are better avoided during breastfeeding as it is not known whether or not most aminosalicylates pass into breast milk.

Child use issues

The safety of aminosalicylates in children has not been established. The use of sulfasalazine is not recommended for patients younger than age 2 because it may cause brain damage.

Symptoms of aminosalicylate overdose

Overdose with the aminosalicylate sulfasalazine may cause dizziness, drowsiness, headache, unconsciousness, lack of appetite (anorexia), abdominal pain, nausea and vomiting.

Overdose can lead to complications that are potentially life-threatening, including the development of:

  • Hemolytic anemia (condition marked by inadequate number of red blood cells)
  • Agranulocytosis (condition marked by insufficient number of white blood cells)
  • Dermatitis (inflammation of the skin)
  • Acidosis (condition marked by excessive acid in the body fluids)
  • Jaundice (condition in which the skin, mucous membranes and whites of the eyes appear yellow as a result of excess bilirubin that cannot be processed by the liver)

Although little is known about the potential for overdose with other aminosalicylates, overdose of olsalazine appears to cause decreased motor activity and diarrhea. Patients exhibiting such symptoms should contact their physician immediately.

Questions for your doctor

Patients may wish to ask their doctor the following questions about aminosalicylates:
  1. I’ve heard that sulfasalazine causes more side effects than other aminosalicylates. Which side affects are associated with this drug?
  2. Will I take an oral preparation, enema or suppository?
  3. If the aminosalicylate I take does not work, is it possible that another drug might be more effective?
  4. Do certain drugs interact poorly with the type of aminosalicylate that I’m taking?
  5. I’m pregnant – does this mean I should not take aminosalicylates?
  6. Do I need to keep using this medication while my condition is in remission?
  7. Which type of medication is more effective, oral or rectal?
  8. Will more effective medications be available in the near future?
  9. Will the use of aminosalicylates prevent the need for surgery for my condition?
  10. Can I take other medications to reduce side effects like headaches and nausea?

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