Asacol HD is a brand-name prescription medication that’s FDA-approved to treat ulcerative colitis (UC) in adults.

UC is a form of inflammatory bowel disease. With UC, you have inflammation (swelling) and ulcers (small sores) in the lining of your colon (large intestine) and rectum.

This condition is long term. But there may be times when it’s either active (causing symptoms) or in remission (not causing as many or any symptoms).

Asacol HD is approved to treat moderately active UC. You’ll typically take the drug for 6 weeks to reduce inflammation in your colon and help relieve UC symptoms. It’s not known if Asacol HD is safe or effective to take for more than 6 weeks.

For more information about UC and how Asacol HD treats it, see the “Asacol HD uses” section below.

Drug details

Asacol HD contains the active drug mesalamine, which is also known as 5-aminosalicylic acid. It belongs to a drug class called aminosalicylates. (A drug class is a group of medications that work in a similar way.)

Asacol HD comes as delayed-release tablets that are taken by mouth.

As a delayed-release drug, Asacol HD is designed to move through your digestive system and release the medication directly in your colon. It doesn’t release the drug sooner in your digestive system like immediate-release drugs do.

Asacol HD tablets are available in one strength: 800 milligrams.

Effectiveness

For information about the effectiveness of Asacol HD, see the “Asacol HD uses” section below.

Asacol HD is a brand-name drug that contains the active drug mesalamine. This active drug is also available as a generic-name medication, called mesalamine tablet, delayed release.

A generic drug is an exact copy of the active drug in a brand-name medication. The generic is considered to be as safe and effective as the original drug. Generics tend to cost less than brand-name drugs.

If you’re interested in taking the generic form of Asacol HD, talk with your doctor or another healthcare professional.

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Drug form and strength

Asacol HD tablets contain the active drug mesalamine. And they’re available in one strength: 800 milligrams (mg).

Asacol HD comes as a delayed-release tablet that you’ll take by mouth.

As a delayed-release drug, Asacol HD is designed to move through your digestive system and release the medication directly in your colon (large intestine). It doesn’t release the drug right away in your digestive system like immediate-release drugs do.

Asacol HD tablets have a special coating that allows them to pass through your stomach and small intestine without being digested. Then, they release their active drug when they reach your colon.

Dosage for ulcerative colitis

Asacol HD is used to treat moderately active ulcerative colitis (UC) in adults. The recommended dosage is 1,600 mg, taken three times per day for 6 weeks. You’ll take two Asacol HD tablets for each dose to reach 1,600 mg.

Asacol HD should be taken without food on an empty stomach. For more information, see the “How to take Asacol HD” section below.

What if I miss a dose?

If you miss a dose of Asacol HD and it’s not time for your next scheduled dose, take the dose as soon as you remember. If it is nearly time for your next dose, skip the missed dose and take your next scheduled dose as usual.

Do not take two doses together to make up for a missed dose. This could increase your risk for side effects. If you have questions about a missed dose, talk with your doctor or pharmacist.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or using a timer. You could also download a reminder app on your phone.

Will I need to use this drug long term?

No, Asacol HD isn’t meant to be used long term. Instead, it’s only used for a 6-week treatment course to reduce UC symptoms. Taking Asacol HD for longer than 6 weeks hasn’t been studied.

However, after you stop Asacol HD, your doctor may prescribe another form of mesalamine (the active drug in Asacol HD). Other forms of mesalamine may be taken long term to manage your condition. Ask your doctor if you’ll need to take another form of the drug after you stop Asacol HD.

Asacol HD can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Asacol HD. These lists do not include all possible side effects.

For more information about the possible side effects of Asacol HD, talk with your doctor or pharmacist. They can give you tips on how to manage any side effects that may be concerning or bothersome.

Note: The Food and Drug Administration (FDA) tracks side effects of drugs it has approved. If you would like to notify the FDA about a side effect you’ve had with Asacol HD, you can do so through MedWatch.

Mild side effects

Mild side effects* of Asacol HD can include:

Most of these side effects may go away within a few days or a couple of weeks. But if they become more severe or don’t go away, talk with your doctor or pharmacist.

* This is a partial list of mild side effects from Asacol HD. To learn about other mild side effects, talk with your doctor or pharmacist, or view Asacol HD’s prescribing information.
† For more information about this side effect, see “Side effect details” below.

Serious side effects

Serious side effects from Asacol HD aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 or your local emergency number if your symptoms feel life threatening or if you think you’re having a medical emergency.

Serious side effects and their symptoms can include:

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

Side effect details

Here are some details on certain side effects this drug may cause.

Headache

People may experience headaches while taking Asacol HD. In clinical studies, headache was the most common side effect reported with this medication.

If you have headaches that are bothersome while you’re taking Asacol HD, tell your doctor or pharmacist. They may be able to recommend a suitable pain medication.

Stomachache and nausea

Digestive side effects, such as stomachache and nausea, may occur with Asacol HD. In clinical studies, these side effects were common.

It’s important to note that if you have stomachache or nausea with Asacol HD, they could be symptoms of serious side effects of the drug. These serious side effects include kidney problems and mesalamine-induced acute intolerance syndrome. Other symptoms of these conditions are described in the “Serious side effects” list above.

If you have troublesome stomachaches or nausea with Asacol HD, talk with your doctor. They can suggest ways to help relieve these side effects. They can also determine whether these symptoms may be a sign of a more serious issue.

Common cold

In clinical studies, common cold was a frequent side effect in people who took Asacol HD.

A cold causes swelling in your nasal passages and throat. Symptoms of a cold can include a stuffy or runny nose and sore throat.

If you have these symptoms while taking Asacol HD, they’ll usually get better on their own in a few days. But if your symptoms are bothersome, you can ask your doctor or pharmacist to recommend a medication to help relieve them.

Allergic reaction

As with most drugs, some people can have an allergic reaction after taking Asacol HD.

Symptoms of a mild allergic reaction can include:

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include:

  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your tongue, mouth, or throat
  • trouble breathing

Call your doctor right away if you have an allergic reaction to Asacol HD, as the reaction could become severe. Call 911 or your local emergency number if your symptoms feel life threatening or if you think you’re having a medical emergency.

As with all medications, the cost of Asacol HD can vary. To find current prices for Asacol HD tablets in your area, check out GoodRx.com.


The cost you find on GoodRx.com is what you may pay without insurance. The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.

Before approving coverage for Asacol HD, your insurance company may require you to get prior authorization. This means your doctor and insurance company will need to communicate about your prescription before the insurance company will cover the drug. The insurance company will review the prior authorization request and decide if the drug will be covered.

If you’re not sure if you’ll need to get prior authorization for Asacol HD, contact your insurance company.

Financial and insurance assistance or coupon

If you need financial support to pay for Asacol HD, or if you need help understanding your insurance coverage, help may be available.

Medicine Assistance Tool and NeedyMeds are two websites offering resources that may help decrease the price you pay for Asacol HD tablets. They also offer tools to help you find low-cost healthcare, as well as educational resources. To learn more, visit their sites.

Also, check with your doctor or pharmacist to see if there are any coupons or cost-saving options for this drug. For more information about saving money on prescriptions, see this article.

Mail-order pharmacies

Asacol HD may be available through a mail-order pharmacy. Using this service may help lower the drug’s cost and allow you to get your medication without leaving home. Some Medicare plans may help cover the cost of mail-order medications.

If you don’t have insurance, you can ask your doctor or pharmacist about online pharmacy options.

Generic version

Asacol HD is available in a generic form called mesalamine tablet, delayed release. A generic drug is an exact copy of the active drug in a brand-name medication. The generic is considered to be as safe and effective as the original drug. And generics tend to cost less than brand-name drugs. To find out how the cost of mesalamine compares to the cost of Asacol HD, visit GoodRx.com.

If your doctor has prescribed Asacol HD and you’re interested in taking mesalamine tablet, delayed release instead, talk with your doctor. They may recommend one version or the other for you. You’ll also need to check your insurance plan, as it may only cover one version.

Here are answers to some frequently asked questions about Asacol HD.

Is Asacol HD used to treat Crohn’s disease?

No, Asacol HD is not approved to treat Crohn’s disease. Instead, it’s only approved to treat moderately active ulcerative colitis (UC).

Crohn’s disease is a form of inflammatory bowel disease that’s similar to UC.

According to the American College of Gastroenterology (ACG), mesalamine hasn’t been found effective for treating active Crohn’s disease. (Mesalamine is the active drug in Asacol HD.) Rather, it’s only been found to have a limited benefit when taken to maintain remission of Crohn’s disease.

During UC remission, its symptoms are reduced or have gone away. To maintain remission, a drug is taken long term to help prevent the condition from getting worse again.

The ACG doesn’t recommend using drugs containing mesalamine, such as Asacol HD, in Crohn’s disease management.

If you are interested in treatments for Crohn’s disease, talk with your doctor.

Does Asacol HD come in strengths of 400 mg, 500 mg, or 1,200 mg?

No, Asacol HD only comes as 800-milligram (mg) tablets. However, your doctor may switch you to Asacol HD from other brand-name drugs that also contain mesalamine. And these drugs may contain different strengths of mesalamine, such as 250 mg, 375 mg, 400 mg, 500 mg, or 1,200 mg.

These drugs, which are taken by mouth like Asacol HD, include:

Keep in mind, Asacol HD tablets are not interchangeable with these drugs. If your doctor switches you to Asacol HD from one of these medications, they’ll recommend that you stop taking the medication before you start Asacol HD. You should not mix and match these medications.

Will Asacol HD cure my condition?

No, Asacol HD won’t cure ulcerative colitis (UC). Currently, there’s no cure for this condition.

Asacol HD treats moderately active UC and can help relieve its symptoms. This is sometimes called inducing remission. But Asacol HD doesn’t cure UC. After you stop taking the drug, it’s still possible your UC may become active and cause symptoms again.

Other medications may be taken long term to maintain UC remission. But Asacol HD isn’t used for this purpose. If you’re interested in taking medications long term to help manage UC, talk with your doctor. They can advise whether this is a good option for you and recommend a suitable medication.

I’m taking generic mesalamine and my doctor is switching me to Asacol HD. What might my dosage be?

Asacol HD contains a delayed-release form* of the active drug mesalamine. Mesalamine is available in several generic forms. (For more information about generics, see the “Asacol HD generic” section above.)

If your doctor switches you from generic delayed-release mesalamine to Asacol HD, you’ll typically take the usual recommended dosage of Asacol HD.

For example, if you take 800-mg generic mesalamine delayed-release tablets, you’ll take 800-mg Asacol HD tablets. This is because these products are equivalent.

However, if your doctor switches you from another dosage form of generic mesalamine to Asacol HD, they’ll recommend you stop taking the generic mesalamine before you start Asacol HD.

This is because these products are not the same. And you should not mix and match them, even if you take the same dosage.

For example, two 400-mg generic mesalamine delayed-release tablets may not produce the same effect as one 800-mg Asacol HD delayed-release tablet. So you should not swap two mesalamine 400-mg delayed-release tablets for one 800-mg Asacol HD tablet. These tablets release the active drug in different ways.

Be sure to check with your doctor or pharmacist about your prescribed dosage of Asacol HD.

* Delayed-release medications release their active drug in your body at a later time after you take them. This is unlike immediate-release medications, which release their active drug sooner in your system.

What if I see particles in my stool during Asacol HD treatment?

While you’re taking Asacol HD, you may sometimes notice a tablet shell or a whole or partial tablet in your stool. This isn’t usually a problem. But if it happens frequently, talk with your doctor. They may need to check that the medication is working properly for you.

Asacol HD works directly in your colon (large intestine) and rectum. The tablet has a special coating that allows it to pass through your stomach and small intestine without being digested. The medication is released when the tablet reaches your colon.

The Food and Drug Administration (FDA) approves prescription drugs such as Asacol HD to treat certain conditions.

Asacol HD for ulcerative colitis

Asacol HD is FDA-approved to treat moderately active ulcerative colitis (UC) in adults.

UC is a form of inflammatory bowel disease. With UC, you have inflammation (swelling) and ulcers (small sores) in the lining of your colon (large intestine), rectum, or both.

The condition is long term. But there may be times when it’s active (causing symptoms) and times when it’s in remission (not causing as many or any symptoms).

Symptoms of active UC may include:

Asacol HD is typically taken for 6 weeks to reduce inflammation in your bowel and help relieve UC symptoms. This is sometimes called inducing remission. It’s not known if Asacol HD is safe or effective to take for more than 6 weeks.

Effectiveness for ulcerative colitis

Asacol HD is an effective treatment for moderately active UC. To find out how the medication performed in clinical studies, see Asacol HD’s prescribing information.

Mesalamine is recommended as a treatment option for active UC according to American Gastroenterological Association guidelines. (Keep in mind, mesalamine is the active drug in Asacol HD.) It’s also recommended in similar guidelines from the American College of Gastroenterology.

Asacol HD and children

Asacol HD isn’t FDA-approved for children under 18 years old. It hasn’t been studied in children.

Asacol HD isn’t known to interact with alcohol. However, drinking alcohol with this medication could worsen certain side effects, such as headache, nausea, and diarrhea.

Keep in mind, Asacol HD is used to treat ulcerative colitis (UC). For some people, drinking alcohol can worsen UC symptoms such as diarrhea, cramping, or bloating.

If you drink alcohol, talk with your doctor about how much is safe for you to drink while taking Asacol HD.

Asacol HD can interact with several other medications. It can also interact with certain foods and interfere with specific lab tests.

Different interactions can cause different effects. For instance, some interactions can interfere with how well a drug works. Other interactions can increase side effects or make them more severe.

Asacol HD and other medications

Below is a list of medications that can interact with Asacol HD. This list does not contain all drugs that may interact with Asacol HD.

Before taking Asacol HD, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you take. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Types of drugs that can interact with Asacol HD include:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs). Taking Asacol HD with NSAIDs could increase your risk for kidney problems. Examples of these drugs include:
  • Azathioprine (Azasan, Imuran) or 6-mercaptopurine. These drugs are sometimes used to treat ulcerative colitis, as is Asacol HD. Taking Asacol HD with these drugs could increase your risk for blood disorders.

Asacol HD and herbs and supplements

There aren’t any herbs or supplements that have been specifically reported to interact with Asacol HD.

However, taking Asacol HD with iron supplements could lead to iron overload (having too much iron in your body). This is because Asacol HD tablets contain iron in their coating.

Before starting Asacol HD, be sure to tell your doctor if you take iron supplements or any other supplements or herbs.

Asacol HD and foods

You should avoid eating food for at least:

  • 2 hours before taking Asacol HD, and
  • 1 hour after taking Asacol HD

This is because taking Asacol HD with food can increase the amount of drug that’s absorbed into your bloodstream. This can increase your risk for side effects. It can also lower the amount of drug that reaches your colon (large intestine). And this could make the medication less effective.

Asacol HD and lab tests

Asacol HD may interfere with certain lab tests that measure levels of normetanephrine in your urine.

Normetanephrine is a substance that’s formed when your body breaks down the hormone norepinephrine. You might have a urine test for normetanephrine if your doctor wants to check for certain rare cancers.

Asacol HD can cause a false-positive result on this urine test. This means the test may show increased levels of normetanephrine, even if your levels are actually within the preferred range

If you need to have a normetanephrine urine test, let your doctor or another healthcare professional know that you’re taking Asacol HD.

You should take Asacol HD according to the instructions your doctor gives you. This medication comes as tablets that you’ll take by mouth.

When to take

You should take Asacol HD three times a day. And you’ll take it for 6 weeks.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or using a timer. You could also download a reminder app on your phone.

Taking Asacol HD with food

Asacol HD should be taken without food on an empty stomach. This means you should take it at least 1 hour before a meal or 2 hours after a meal.

Talk with your doctor or pharmacist if you’re unsure of when to take the tablets.

Can Asacol HD be crushed, split, or chewed?

No, Asacol HD tablets cannot be crushed, split, or chewed. These tablets have a special coating that allows them to move through your stomach and small intestine without being digested.

To avoid damaging this coating, you should swallow Asacol HD tablets whole. This is easier to do if you take the tablets with a beverage.

If you have trouble swallowing pills, see this article or talk with your doctor.

Asacol HD is used to treat moderately active ulcerative colitis (UC).

What ulcerative colitis is

UC is a long term condition that affects your colon (large intestine) and rectum. The severity of symptoms tends to change over time. There may be times when the disease is active and causes symptoms. There may also be times when the disease goes into remission and its symptoms are reduced or go away.

When UC is active, the lining of your colon, rectum, or both become swollen. Ulcers (small sores) may also develop in these linings.

What Asacol HD does

Asacol HD contains the active drug mesalamine. This is also known as 5-aminosalicylic acid. Asacol HD belongs to the drug class called aminosalicylates. (A drug class is a group of medications that work in a similar way.)

Aminosalicylate drugs work by reducing inflammation (swelling) in the lining of your colon and rectum.

In people with UC, cells in these linings make certain substances that cause inflammation. Aminosalicylate drugs stop the cells from producing these substances. But it’s not fully understood how the drugs work.

Asacol HD works directly in your colon and rectum. The tablet has a special coating that allows it to pass through your stomach and small intestine without being digested. The active drug is released when the tablet reaches your colon. Here, it acts locally on the cells that cause inflammation in the lining of your colon and rectum.

By reducing the inflammation, Asacol HD also allows ulcers in your colon and rectum to heal.

Both of these effects help reduce symptoms of UC.

How long does it take to work?

Asacol HD starts working to reduce inflammation in your bowel a few hours after you take your first dose. But it might take a few weeks before you notice relief of your symptoms. Most people’s symptoms are reduced or gone with a 6-week course of treatment.

Asacol HD hasn’t been studied in pregnancy, so it’s not known if it’s safe to take the drug during pregnancy.

However, limited information about mesalamine use during pregnancy suggests that the drug doesn’t cause fetal harm in humans. (Keep in mind, mesalamine is the active drug in Asacol HD.)

In animal studies, mesalamine didn’t cause fetal harm. However, animal studies don’t always predict what will happen in humans.

On the other hand, having active ulcerative colitis (UC) during pregnancy is known to increase the risk of premature birth or low birth weight. And Asacol HD is used to treat active UC.

Because of these possible complications, the American Gastroenterological Association recommends using mesalamine-containing drugs to treat active UC during pregnancy. This organization considers the benefits of the medication to outweigh its risks.

If you’re pregnant or planning to become pregnant, talk with your doctor about the possible risks and benefits of taking Asacol HD.

It’s unknown if Asacol HD is safe to take during pregnancy. If you’re sexually active and you or your partner can become pregnant, talk with your doctor about your birth control needs while you’re taking Asacol HD.

For more information about taking Asacol HD during pregnancy, see the “Asacol HD and pregnancy” section above.

It’s not known if Asacol HD is safe to take while breastfeeding.

Asacol HD contains the active drug mesalamine. While you’re taking Asacol HD, small amounts of mesalamine may pass into breast milk. There’s a small risk that this could cause diarrhea in a child who’s breastfed.

However, guidance from the American Gastroenterological Association suggests it’s usually safe to breastfeed while taking mesalamine.

If you’re breastfeeding or plan to breastfeed, talk with your doctor about the best way to feed your child while you take Asacol HD. If you breastfeed while taking Asacol HD, be sure to tell your doctor right away if your child has diarrhea.

This drug comes with several precautions. Before taking Asacol HD, talk with your doctor about your health history. Asacol HD may not be right for you if you have certain medical conditions or other factors affecting your health. These include:

  • Allergic reaction. Asacol HD belongs to the aminosalicylate drug class. You should not take Asacol HD if you’ve ever had an allergic reaction to it, any of its ingredients, or to other aminosalicylate or salicylate drugs. Examples of these drugs include aspirin, balsalazide (Colazal), olsalazine (Dipentum), and sulfasalazine (Azulfidine). Ask your doctor about other medications that might be better options for you.
  • Older age. If you’re age 65 years or older, you may have a higher risk for side effects with Asacol HD. Specifically, Asacol HD may decrease your blood cell counts. Your doctor may order blood tests to check your blood cell levels while you’re taking Asacol HD.
  • Liver problems. If you have liver problems, taking Asacol HD could make these worse or cause liver failure. Talk with your doctor about whether Asacol HD is right for you. If you take Asacol HD, your doctor will monitor your liver during treatment. If your liver problems get worse, your doctor may recommend that you stop taking Asacol HD.
  • Kidney problems. Asacol HD may cause kidney problems. If you already have kidney problems, or you’ve had kidney disease, talk with your doctor about whether Asacol HD is right for you. Your doctor will monitor your kidney function while you take Asacol HD. If your kidney function worsens, your doctor may recommend you stop treatment.
  • Skin conditions such as eczema or dermatitis. If you have a skin condition such as eczema or dermatitis, taking Asacol HD may make your skin react more severely than usual to sunlight. Talk with your doctor about ways to protect your skin while you take Asacol HD. These include using sunscreen, wearing clothing that covers your skin, and avoiding direct sunlight.
  • Iron overload. The coating of Asacol HD tablets contains iron. These tablets may not be suitable for you if you’re at risk of iron overload (having too much iron in your body). You could be at risk of iron overload if you take iron supplements or if you have frequent blood transfusions. In these cases, your doctor will consider all of your sources of iron before prescribing Asacol HD.
  • Pregnancy. It’s not known if Asacol HD is safe to take during pregnancy. For more information, see the “Asacol HD and pregnancy” section above.
  • Breastfeeding. It’s unknown if Asacol HD is safe to take while breastfeeding. Mesalamine (the active drug in Asacol HD) may pass into breast milk in small amounts. For more information, see the “Asacol HD and breastfeeding” section above.

Note: For more information about the potential negative effects of Asacol HD, see the “Asacol HD side effects” section above.

Taking more than the recommended dosage of Asacol HD can lead to serious side effects. Do not take more Asacol HD than your doctor recommends.

Overdose symptoms

Symptoms of an overdose can include:

What to do in case of overdose

If you think you’ve taken too much of this drug, call your doctor. You can also call the American Association of Poison Control Centers at 800-222-1222 or use its online tool. But if your symptoms are severe, call 911 or your local emergency number, or go to the nearest emergency room right away.

When you get Asacol HD from the pharmacy, the pharmacist will add an expiration date to the label on the bottle. This date is typically 1 year from the date they dispensed the medication.

The expiration date helps guarantee that the medication is effective during this time. The current stance of the Food and Drug Administration is to avoid taking expired medications. If you have unused medication that has gone past the expiration date, talk with your pharmacist about whether you might still be able to take it.

Storage

How long a medication remains good to take can depend on many factors, including how and where you store the medication.

Asacol HD tablets should be stored at room temperature, 20°C to 25°C (68°F to 77°F). They should be in a tightly sealed container away from light. Avoid storing this medication in areas where it could get damp or wet, such as bathrooms.

Disposal

If you no longer need to take Asacol HD and have leftover medication, it’s important to dispose of it safely. This helps prevent others, including children and pets, from taking the drug by accident. It also helps keep the drug from harming the environment.

This article provides several useful tips on medication disposal. You can also ask your pharmacist for information about how to dispose of your medication.

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.