Aminosalicylates

Types and differences of aminosalicylates

Aminosalicylates are available in four different varieties:

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.

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.

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.