Asacol (mesalamine) is a prescription medication primarily used in the treatment of inflammatory bowel diseases (IBD), such as ulcerative colitis and Crohn’s disease. It belongs to a class of drugs known as aminosalicylates, which work by reducing inflammation in the digestive tract.

How Does Asacol Work?

The exact mechanism of action of Asacol is not fully understood. However, it is believed to exert its therapeutic effects locally in the colon by inhibiting the production of inflammatory mediators and scavenging free radicals. This helps to reduce inflammation, alleviate symptoms, and promote mucosal healing in patients with ulcerative colitis or Crohn’s disease.

Asacol is formulated to release mesalamine, the active ingredient, in a controlled manner as it passes through the digestive tract. This targeted delivery allows for optimal efficacy while minimizing systemic absorption and potential side effects.

Precautions and Warnings With Asacol

Before starting Asacol, it is crucial to consider certain precautions and be aware of potential warnings associated with its use. Some important precautions and warnings to be mindful of include:


Asacol is contraindicated in patients with a known hypersensitivity to mesalamine or any other components of the formulation. Individuals with a history of allergic reactions to salicylates, such as aspirin, should exercise caution when using Asacol.

Special Populations

  • Pregnancy: Asacol should be used with caution during pregnancy, particularly during the first trimester.
  • Breastfeeding: It is not known whether mesalamine is excreted in human breast milk.
  • Pediatrics: The safety and efficacy of Asacol in pediatric patients have not been established.

Monitoring Parameters

Patients taking Asacol may require regular monitoring to assess treatment response and detect any potential adverse effects. Monitoring parameters may include:

  • Clinical symptoms of inflammatory bowel disease (e.g., abdominal pain, diarrhea, rectal bleeding)
  • Laboratory tests, such as complete blood count (CBC) and liver function tests, to monitor for signs of hematologic or hepatic abnormalities
  • Renal function tests, as mesalamine may rarely cause renal impairment

Asacol Side Effects

While Asacol is generally well-tolerated, like any medication, it may cause side effects in some individuals. Side effects associated with Asacol may include: 

Side EffectSeverityDescription
Abdominal or stomach cramps or pain (mild)MildMild discomfort or pain in the abdominal or stomach area.
AcneMildSkin condition characterized by the appearance of pimples, typically on the face, neck, chest, and back.
Back painMildDiscomfort or pain experienced in the back region.
BloatingMildFeeling of fullness or tightness in the abdomen due to excess gas.
Blood pressure changesMildFluctuations in blood pressure levels, which may be temporary.
Changed sense of touchMildAltered perception of touch sensation.
ConstipationMildDifficulty in passing stools, often associated with infrequent bowel movements and hard stools.
Decreased sperm countMildReduction in the number of sperm cells in semen, potentially affecting fertility.
Diarrhea (mild)MildPassage of loose or watery stools, often occurring in mild cases.
DizzinessMildSensation of lightheadedness or unsteadiness, often accompanied by a spinning sensation.
Ear or throat painMildDiscomfort or pain localized in the ears or throat.
FatigueMildFeeling of tiredness or exhaustion that may interfere with daily activities.
Hair lossMildAbnormal shedding of hair from the scalp, which may lead to thinning or baldness.
Headache (mild)MildPain or discomfort in the head region, often occurring in mild cases.
GasMildExcess accumulation of gas in the digestive tract, leading to bloating and discomfort.
Increased sensitivity of the skin to sunlightMildHeightened response of the skin to sunlight, potentially resulting in sunburn or skin irritation.
Increased urge to have a bowel movementMildHeightened sensation or urgency to pass stools.
Irritation of the rectal areaMildDiscomfort or inflammation affecting the rectal region.
Muscle or joint painMildDiscomfort or pain experienced in muscles or joints.
NauseaMildFeeling of queasiness or discomfort in the stomach, often accompanied by the urge to vomit.
TirednessMildState of physical or mental exhaustion, often leading to fatigue.
TremorMildInvoluntary shaking or trembling of the body, typically affecting the hands, arms, or legs.
VomitingMildForceful expulsion of stomach contents through the mouth, often accompanied by nausea.
WeaknessMildReduced physical or mental strength, often leading to fatigue or lethargy.
Burning pain or discomfort around the anusSevereIntense burning sensation or discomfort in the area surrounding the anus.
FeverSevereElevated body temperature, often accompanied by other symptoms of illness.
Fast or pounding heartbeatSevereRapid or irregular heartbeat, which may indicate underlying cardiovascular issues.
Kidney stonesSevereHard deposits of minerals and salts that form in the kidneys, leading to severe pain and other symptoms.
Lupus-like rashSevereCharacteristic rash resembling a butterfly shape on the face or arms, associated with systemic lupus erythematosus (SLE).
Rectal bleedingSeverePassage of blood from the rectum, which may indicate underlying gastrointestinal issues.
Numbness or tingling in hands and feetSevereLoss of sensation or abnormal sensations, typically in the extremities.
Severe headacheSevereIntense or debilitating pain in the head region, requiring immediate medical attention.
Severe stomach painSevereIntense or debilitating pain in the abdominal region, often requiring medical evaluation.
Signs of anemiaSevereSymptoms associated with low red blood cell count, including dizziness, pale skin, and weakness.
Signs of kidney problemsSevereSymptoms indicating impaired kidney function, such as changes in urination patterns or blood in the urine.
Signs of infectionSevereSymptoms suggestive of a systemic infection, including fever, chills, and weakness.
Signs of liver problemsSevereSymptoms indicating liver dysfunction, such as jaundice (yellowing of the skin) or abdominal pain.
Skin rash and itchingSevereRedness, irritation, and itching of the skin, often accompanied by rash or hives.
Symptoms of lung inflammationSevereRespiratory symptoms indicating inflammation or infection in the lungs, such as cough, fever, and difficulty breathing.
Unusual bruising or bleedingSevereAbnormal bleeding or bruising that may indicate underlying bleeding disorders or other medical conditions.
Vision changesSevereAlterations in vision, such as blurriness or difficulty focusing, requiring prompt evaluation by an eye specialist.
Worsening symptomsSevereDeterioration or exacerbation of existing symptoms, necessitating medical attention.

Drug Interactions With Asacol

Asacol may interact with other medications, supplements, or substances, potentially affecting its effectiveness or increasing the risk of adverse effects. Some notable drug interactions with Asacol include:

BaricitinibJanus kinase (JAK) inhibitor
Cancer medicationsChemotherapy agents
Cyclosporine (Restasis)Immunosuppressant
DigoxinCardiac glycoside
EverolimusmTOR inhibitor
Folic acidVitamin supplement
HydroxyureaAntineoplastic agent
LenalidomideImmunomodulatory agent
NSAIDsNonsteroidal anti-inflammatory drugs
ObinutuzumabMonoclonal antibody
PropylthiouracilAntithyroid agent
Protein kinase inhibitorsTargeted cancer therapy
SirolimusmTOR inhibitor
Varicella vaccineLive attenuated vaccine
ZidovudineAntiretroviral medication

Asacol Strengths and Dosages

Available Strengths

  • Delayed-release tablets: 400 mg
  • Extended-release capsules: 800 mg

Recommended Dosages

The recommended dosage of Asacol may vary depending on the patient’s condition and individual response to treatment. Generally, the typical dosages for adults with ulcerative colitis are:

  • Mild to moderate active disease:4 to 4.8 grams per day, divided into two or three doses
  • Maintenance of remission:6 grams per day, administered as a single dose or divided into two doses


  • Asacol tablets should be swallowed whole with water and should not be crushed, chewed, or broken.
  • Extended-release capsules should be taken whole with water and should not be opened, chewed, or crushed.
  • The medication can be taken with or without food, as directed by a healthcare provider.

Cost of Asacol in America

At this time of writing, reports the cost for Asacol HD oral delayed release tablet 800 mg to be approximately around $1,775 for a supply of 180 tablets.

Patients are encouraged to check with their local pharmacies, insurance providers, or explore patient assistance programs to determine the most cost-effective option for obtaining Asacol.

Alternatives of Asacol 

While Asacol is an effective medication for managing ulcerative colitis and Crohn’s disease, there may be alternative treatment options available:

  • Other aminosalicylates, such as sulfasalazine or mesalamine formulations with different delivery mechanisms (e.g., rectal suppositories or enemas)
  • Corticosteroids, which may be used for short-term management of acute flare-ups
  • Immunomodulators, such as azathioprine, 6-mercaptopurine, or methotrexate, which work by suppressing the immune system to reduce inflammation
  • Biologic agents, including tumor necrosis factor (TNF) inhibitors (e.g., infliximab, adalimumab), integrin receptor antagonists (e.g., vedolizumab), or interleukin inhibitors (e.g., ustekinumab), which target specific pathways involved in the inflammatory response

FAQs of Asacol

What is the difference between Asacol and Asacol HD?

Asacol (mesalamine) and Asacol HD are both medications used to treat inflammatory bowel disease (IBD), such as ulcerative colitis and Crohn’s disease. The main difference between the two is their dosage form and strength. Asacol contains mesalamine in delayed-release tablets, while Asacol HD contains mesalamine in higher strength extended-release tablets, allowing for less frequent dosing.

What is Asacol?

Asacol is a prescription medication containing mesalamine, which belongs to a class of drugs known as aminosalicylates. It is used to treat mild to moderate active ulcerative colitis and to maintain remission of ulcerative colitis.

Who makes Asacol?

Asacol is manufactured by Tillotts Pharma AG.

What drug class does Asacol belong to?

Asacol belongs to the drug class known as aminosalicylates. These medications work by reducing inflammation in the colon and rectum, thereby helping to relieve symptoms of ulcerative colitis.

Is there a generic version of Asacol available?

Yes, generic versions of Asacol, containing mesalamine, are available. These generics may be marketed under different brand names but contain the same active ingredient and are equivalent in quality and efficacy to the brand-name medication.

How long does it take for Asacol to work?

The onset of action of Asacol may vary from person to person. Some patients may experience symptom relief within a few days of starting treatment, while others may require several weeks for noticeable improvement.

IMPORTANT NOTE: The information provided here is for educational purposes only and is not intended to serve as medical advice, diagnosis, or treatment recommendations. It should not be taken as an endorsement of any specific medication or treatment. Individual health conditions and responses to treatment can vary greatly; therefore, this information should not be seen as a guarantee of safety, suitability, or effectiveness for any particular individual. Always consult with a healthcare professional for personalized medical advice and before making any decisions regarding your health or treatment plans.

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