Midamor (Amiloride) - Oral


Increased potassium levels in the blood can occur while taking Midamor (amiloride). High potassium levels in the blood are more likely to happen in people with poor kidney function, diabetes, those 65 years and older, or people who are severely ill. If left untreated, high potassium levels can be deadly. Therefore, potassium levels in the blood must be checked frequently, especially when first receiving Midamor, when the dosage is changed, or with any illness or medication that can affect how the kidneys work.  

What Is Midamor?

Midamor (amiloride) is a prescription oral diuretic (water pill) medication used in congestive heart failure or high blood pressure (hypertension) to get rid of extra salt and water in the body.

It belongs to the class of medications referred to as potassium-sparing diuretics because they prevent potassium loss. It is often used in addition to another diuretic.

Amiloride is available in tablet form to be taken by mouth.

Drug Facts

Generic Name: Amiloride

Brand Name(s): Midamor

Drug Availability: Prescription

Administration Route: Oral

Therapeutic Classification: Diuretic

Available Generically: Yes

Controlled Substance: N/A

Active Ingredient: Amiloride hydrochloride

Dosage Form(s): Tablet

What Is Midamor Used For?

Midamor, which contains the active ingredient amiloride, is used in combination with other medications to:

  • Treat high blood pressure
  • Treat edema (excess body fluid) in people with congestive heart failure
  • Prevent hypokalemia (low potassium levels)

It works by getting rid of excess salt and water through the urine.

Amiloride has a boxed warning due to the risk of increasing potassium levels, which can be deadly if not treated.

How to Take Midamor

Treatment regimens for Midamor vary based on what you're being treated for. It is important to always take this medication as directed by your healthcare provider. 

The usual dose of Midamor is one tablet daily with food or milk. This medication, and other medications for blood pressure, should be taken even if you are feeling well. High blood pressure is often regarded as the “silent killer.” Even if you are feeling healthy, you may still have high blood pressure and be at risk for further complications like a heart attack or stroke.


Store all forms of Midamor at room temperature (between 68 F and 77 F) in a dry place. Do not store it in the bathroom or kitchen. Containers should be closed tightly and kept away from direct sunlight, children, and pets. 

Off-Label Uses

In some instances Midamor may be prescribed for reasons other than what has been approved by the Food and Drug Administration (FDA). This is known as off-label use. For example, scientific evidence has shown that amiloride can be beneficial for treating ascites (fluid buildup in the abdominal area).

The initial dose may be 10 milligrams (mg) twice daily. Your healthcare provider may adjust the dose every few days by 10 milligrams to a maximum dose of 30 milligrams twice daily as needed.

How Long Does Midamor Take to Work?

Midamor works relatively quickly after use, typically within two hours after an oral dose. It reaches its peak at six to 10 hours.

What Are the Side Effects of Midamor?

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 pharmacist or a healthcare provider. You may report side effects to the FDA at www.fda.gov/medwatch or 1-800-FDA-1088.

Common Side Effects

The most common side effects of Midamor include:

  • Diarrhea 
  • Headache
  • Lack of appetite 
  • Nausea or vomiting

There may be other side effects. Contact your pharmacist or healthcare provider for any further questions or concerns about side effects.

Severe Side Effects

Life-threatening side effects from Midamor are rare. However, some symptoms are severe and should not be taken lightly. Get medical help immediately if you experience symptoms such as:

  • Signs of hyperkalemia (high potassium) including but not limited to an abnormal heartbeat, confusion, weakness, dizziness, shortness of breath, or numbness
  • Signs of an allergic reaction including but not limited to rash; tightness in the chest or throat; or trouble breathing, swallowing, or talking
  • Muscle weakness or pain
  • Slowed heartbeat 

Although rare, call your healthcare provider right away if you experience any of these serious side effects. Dial 911 if your symptoms feel life threatening or if you think you’re having a medical emergency. 

Long-Term Side Effects

Long-term use of Midamor should be only at the approval of your healthcare provider. Taking this medication for an extended period strongly affects urination, sodium loss, and blood potassium levels. It is extremely important to use it as directed.

Report Side Effects

Midamor 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 online or by phone (800-332-1088).

Dosage: How Much Midamor 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 (tablets):
    • For hypertension or edema:
      • Adults—5 milligrams (mg) once a day. Your doctor may increase your dose if needed.
      • Children—Use and dose must be determined by your doctor .


Midamor is not recommended if you have a creatinine clearance less than 10 milliliters (mL) per minute, which would indicate that the kidneys are not working well.

This medication has a boxed warning about the risk of developing high potassium in the blood in people with kidney problems or diabetes, those who are 65 and older, or people who are severely ill. If you fall into any of these categories, constant monitoring of potassium levels is required when starting this medication or when changing the dose.

Missed Dose

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue your regular intake schedule. Do not take extra doses or multiple doses at the same time.

Overdose: What Happens If I Take Too Much Midamor?

If an overdose does occur with Midamor, you may have symptoms of dehydration and electrolyte imbalance. Seek medical attention immediately if you suspect you have taken too much of this medication.

What Happens If I Overdose on Midamor?

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

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


Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your progress at regular visits to make sure this medicine is working properly and to decide if you should continue to take it. Blood tests may be needed to check for unwanted effects .

Do not take other medicines unless they have been discussed with your doctor. This especially includes potassium supplements or salt substitutes containing potassium .

This medicine may increase the amount of potassium in your blood. Check with your doctor right away if you are having abdominal pain; confusion; difficulty breathing; irregular heartbeats; nausea or vomiting; nervousness; numbness or tingling in the hands, feet, or lips; shortness of breath; or weakness or heaviness of the legs .

What Are Reasons I Shouldn’t Take Midamor?

Do not use this medication if you:

  • Have high potassium levels in the blood
  • Have poor kidney function or kidneys that produce little to no urine
  • Are allergic to Midamor or any of its ingredients

What Other Medications Interact With Midamor?

Certain medications may decrease the effects of Midamor or worsen side effects by reducing blood pressure or increasing potassium levels. These include but are not limited to:

This is not a complete list of potential drug interactions that can occur. Tell your healthcare provider about all prescription and over-the-counter (OTC) medications, vitamins, or herbal supplements you take.

What Medications Are Similar?

Multiple classes of diuretic medications are also used to remove excess salt and water in the body. The following diuretics are also used similarly to Midamor:

This is a list of other diuretic drugs. It is NOT a list of drugs recommended to take with Midamor. Talk to your pharmacist or healthcare provider if you have questions. 

Frequently Asked Questions

  • Should I take Midamor right before bedtime?

    It is recommended not to take Midamor too close to bedtime to prevent urination from disrupting sleep. It helps to take this medication around the same time every day.

  • Can Midamor cause dehydration?

    Yes, diuretics have the potential to cause dehydration due to their mechanism of action. Make sure to drink enough fluids throughout the day to prevent this from occurring.

  • Are there any dietary restrictions that come with taking Midamor?

    It is recommended to avoid supplements and/or salt substitutes that contain potassium. High potassium levels can lead to serious health complications.

    For further questions about diet while on this medication, consult with your healthcare provider.

How Can I Stay Healthy While Taking Midamor?

To stay healthy while taking Midamor, use it exactly as directed by your healthcare provider or pharmacist.

Adhering to the prescribed regimen is the only way to maximize the benefits of this medication. Routine follow-up appointments with your healthcare provider are necessary to ensure its safe and effective use and minimize the risk of unwanted side effects. It is also important to check your blood pressure regularly. You can get this checked by a healthcare provider or do it yourself at home with a blood pressure monitor.

Additionally, eat a healthy, well-balanced diet and stick to a regular exercise plan. Consult your healthcare provider or a registered dietitian nutritionist on the appropriate foods to eat and what you should avoid.

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.

The author would like recognize and thank Faith Awoniyi for contributing to this article.

5 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. DailyMed. Label: Amiloride hydrochloride tablet.

  2. Angeli P, Dalla Pria M, De Bei E, et al. Randomized clinical study of the efficacy of amiloride and potassium canrenoate in nonazotemic cirrhotic patients with ascites. Hepatology. 1994;19(1):72-79.

  3. Biggins SW, Angeli P, Garcia-Tsao G, et al. Diagnosis, evaluation, and management of ascites, spontaneous bacterial peritonitis and hepatorenal syndrome: 2021 practice guidance by the American Association for the Study of Liver Diseases. Hepatology. 2021;74(2):1014-1048. doi:10.1002/hep.31884

  4. Prescribers' Digital Reference. Amiloride hydrochloride - drug summary.

  5. Rose BD. Diuretics. Kidney Int. 1991;39(2):336-352. doi:10.1038/ki.1991.43.