Aemcolo (Rifamycin) - Oral

What Is Aemcolo?

Aemcolo (rifamycin) is an antibiotic prescription medication used to treat travelers’ diarrhea caused by certain types of bacteria.

Rifamycin binds to bacterial RNA polymerase to stop the growth of diarrhea-causing bacteria. It is a semisynthetic derivative of rifampin, an antibiotic used to treat tuberculosis.

Aemcolo is available as an extended-release tablet to take by mouth.

Drug Facts

Generic Name: Rifamycin

Brand Name(s): Aemcolo

Drug Availability: Prescription 

Administration Route: Oral

Therapeutic Classification: Antibiotic

Available Generically: No

Controlled Substance: N/A

Active Ingredient: Rifamycin

Dosage Form(s): Delayed-release tablet

What Is Aemcolo Used For?

The Food and Drug Administration (FDA) has approved Aemcolo to treat travelers’ diarrhea caused by noninvasive strains of Escherichia coli (E. coli) in adults.

Travelers’ diarrhea is the most common travel-related illness and often occurs after consuming contaminated food or beverages. Travelers’ diarrhea can happen anywhere, but you’re at a higher risk if you travel to certain parts of Asia, the Middle East, Africa, Mexico, and Central and South America.

Symptoms of traveler’s diarrhea include the sudden onset of watery diarrhea, abdominal cramping, and pain. More severe cases can also cause vomiting, fever, and bloody diarrhea.

Travelers’ diarrhea can be caused by bacteria, viruses, or other pathogens. Aemcolo targets certain bacteria. It is not an appropriate treatment if you have a fever or blood in your stool since these symptoms are often caused by pathogens that Aemcolo can’t treat.

How to Take Aemcolo

Your healthcare provider will likely prescribe Aemcolo twice daily—two tablets in the morning and two tablets at night—for three days. You should take each dose of Aemcolo with a full glass of liquid (6 to 8 ounces). Do not take Aemcolo with alcohol. Be sure to swallow the tablets whole without cutting, crushing, or chewing them.


Aemcolo should be stored at room temperature (68 F to 77 F). Keep it securely stored and out of reach of children and pets. Do not store it in the bathroom.

How Long Does Aemcolo Take to Work?

Aemcolo typically takes two days to improve diarrhea symptoms, but it’s important to finish the full three days of treatment, even if you feel better. Contact your healthcare provider if your diarrhea gets worse or lasts longer than 48 hours—they may need to prescribe a different medication.

What Are the Side Effects of Aemcolo?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your healthcare provider. You may report side effects to the FDA at or 1-800-FDA-1088.

Common Side Effects

Aemcolo is generally well-tolerated, but you may experience side effects. Let your healthcare provider know if you develop any side effects that bother you or don’t go away.

Common side effects can include constipation and headache.

Severe Side Effects

Rarely, Aemcolo may cause serious side effects. Call your healthcare provider immediately if you develop any severe reactions. Call 911 if your symptoms feel life-threatening or you think you’re having a medical emergency.

Severe side effects include:

  • An allergic reaction: Symptoms may include a rash, hives, trouble breathing, or swelling of the face, mouth, tongue, or throat.
  • A severe form of diarrhea called C. diff-associated diarrhea (CDAD): CDAD can occur during treatment or a few months after treatment has ended. Let your healthcare provider know if you develop blood in your stools, stomach pain or cramps, or very loose or watery stools.

Report Side Effects

Aemcolo may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Aemcolo Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (delayed-release tablets):
    • For traveler's diarrhea:
      • Adults—388 milligrams (mg) (2 tablets) 2 times a day for 3 days.
      • Children—Use and dose must be determined by your doctor.

Missed Dose

If you forget to take your dose of Aemcolo, take it as soon as you remember. If it’s almost time for your next dose, skip the missed dose and resume your regular dosing schedule. Do not double up or take extra Aemcolo.

Overdose: What Happens If I Take Too Much Aemcolo?

Only a small amount of Aemcolo gets absorbed into your body—the rest remains in your gastrointestinal (GI) tract where it fights the bacteria causing your travelers’ diarrhea. For this reason, taking too much Aemcolo likely wouldn’t cause any serious effects. However, it’s important to follow your prescription instructions carefully and only take your prescribed dose of Aemcolo. If you are unsure, ask your healthcare provider or pharmacist.

What Happens If I Overdose on Aemcolo?

If you think you or someone else may have overdosed on Aemcolo, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Aemcolo, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your progress to see if the medicine is working properly and to check for unwanted effects.

Call your doctor if your diarrhea does not improve or if it gets worse within 48 hours.

Check with your doctor right away if you develop a fever or have blood in your stool.

Antibacterials, including rifamycin may also cause diarrhea, and in some cases it can be severe. It may occur 2 months or more after you stop using this medicine. Do not take any medicine to treat diarrhea without first checking with your doctor. Diarrhea medicines may make the diarrhea worse or make it last longer. If you have any questions about this or if mild diarrhea continues, or gets worse, check with your doctor.

You can become dehydrated if too much fluid is lost from the body with diarrhea. Make sure you drink plenty of fluids while you have diarrhea. Check with your doctor right away if you have more than one of the following symptoms: decreased urination, dizziness, dry mouth, increased thirst, or lightheadedness.

What Are Reasons I Shouldn’t Take Aemcolo?

Certain conditions increase your risk of developing complications from Aemcolo. Share your medical history with your healthcare provider, including allergies and health conditions.

Do not take Aemcolo if you are allergic to:

  • Mycobutin (rifabutin)
  • Priftin (rifapentine) 
  • Rifampin
  • Rifamycin
  • Xifaxan (rifaxamin)

What Other Medications Interact With Aemcolo?

Aemcolo is designed to stay in your GI tract, where it can target the bacteria causing your travelers’ diarrhea. Since only a small amount of medicine gets absorbed into your body, there aren’t many drug interactions that you need to worry about. Still, it’s important to let your healthcare provider and pharmacist know about all your medications, including over-the-counter (OTC) nonprescription products and vitamins or herbal supplements.

What Medications Are Similar?

Aemcolo is an antibiotic used to treat travelers’ diarrhea. Other antibiotics also prescribed for travelers’ diarrhea include Xifaxan (rifaximin) and Zithromax (azithromycin).

Zithromax may be used to treat more severe cases of travelers’ diarrhea, including those with a fever or bloody stools. Aemcolo and Xifaxan should not be used in these cases since they are unlikely to be effective. Because Aemcolo stays in your GI tract, side effects are minimal, and drug interactions are not as much of a concern as other treatment options.

These are antibiotics also prescribed to treat travelers’ diarrhea. They are not recommended to take with Aemcolo. You should not take these drugs together. Discuss any questions or concerns about your treatment with a pharmacist or healthcare provider.

Frequently Asked Questions

  • What is Aemcolo used for?

    Aemcolo is used to shorten the duration of travelers’ diarrhea caused by certain types of bacteria.

  • How does Aemcolo work?

    Aemcolo is an antibiotic. It works by slowing down the growth of the bacteria that cause travelers’ diarrhea.

  • How long does it take for Aemcolo to work?

    You should begin to notice an improvement in your symptoms within two days of starting your medication. However, make sure to finish your treatment regimen, even if your symptoms resolve.

    Contact your healthcare provider if your diarrhea gets worse, lasts for more than 48 hours, or if you have a fever or blood in your stool.

  • What are the side effects of Aemcolo?

    The most common side effects of Aemcolo include constipation and headache.

How Can I Stay Healthy While Taking Aemcolo?

Nobody wants to get sick on vacation, and frequent trips to the bathroom can put a damper on your plans. The good news is that most cases of travelers’ diarrhea will resolve without any specific treatment. The best thing you can do is stay well hydrated.

Your healthcare provider may prescribe an antibiotic like Aemcolo to help you feel better sooner. While you can expect to see symptom improvement shortly after starting treatment, seek immediate medical attention if you develop diarrhea with severe:

  • Fever
  • Abdominal pain
  • Vomiting
  • Blood in your stool

These could be signs of a more severe infection.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. LiverTox: clinical and research information on drug-induced liver injury [Internet]. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012-. Rifamycin.

  2. DailyMed. Label: Aemcolo- rifamycin tablet, delayed release.

  3. Centers for Disease Control and Prevention. Travelers’ diarrhea.

  4. Riddle MS, Connor BA, Beeching NJ, et al. Guidelines for the prevention and treatment of travelers' diarrhea: a graded expert panel report. J Travel Med. 2017;24(suppl_1):S57-S74. doi:10.1093/jtm/tax026

By Christina Varvatsis, PharmD
Christina Varvatsis is a hospital pharmacist and freelance medical writer. She is passionate about helping individuals make informed healthcare choices by understanding the benefits and risks of their treatment options.