What is Moduretic?

Moduretic is a medication used to treat fluid retention (edema) and high blood pressure (hypertension). It is a combination of two drugs, amiloride and hydrochlorothiazide. Amiloride works by preventing your body from absorbing too much salt, which can cause fluid retention. Hydrochlorothiazide is a “water pill” (diuretic) that causes you to make more urine, which helps your body get rid of extra salt and water.


Health Benefits

Moduretic can be used to treat fluid retention (edema) and high blood pressure (hypertension).

Fluid retention is a condition in which your body retains too much fluid. This can cause swelling in your hands, feet, ankles, or lower legs.

High blood pressure is a condition in which the force of your blood against your artery walls is too high. This can put strain on your heart and damage your arteries. High blood pressure can lead to heart disease, stroke, or kidney failure.

Moduretic may also be used for purposes not listed in this medication guide.

Side Effects

Moduretic can cause serious side effects. Tell your doctor if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

fast or pounding heartbeats;

feeling like you might pass out;

little or no urinating;

swelling in your ankles or feet;

shortness of breath, coughing up blood;

jaundice (yellowing of your skin or eyes); or

high potassium (slow heart rate, weak pulse, muscle weakness, tingly feeling).

Moduretic can cause high potassium levels. This effect can be dangerous if you have other medical conditions that affect your potassium levels. If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Common Moduretic side effects may include:

muscle weakness or cramps;

nausea, vomiting, diarrhea;

dizziness, headache;

sleep problems (insomnia);

tired feeling; or


This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.


The usual starting dose is one tablet daily. Your doctor may increase your dose if needed.

If you take Moduretic for high blood pressure, it may take 2 to 4 weeks for your blood pressure to start to decrease.

For best results, keep using the medication as directed. Your blood pressure will need to be checked often, and you may need other blood tests at your doctor’s office.

If you are being treated for fluid retention, you may need to follow a low-salt diet while you are taking Moduretic. This will help prevent buildup of too much water in your body. Follow the instructions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand.

Take Moduretic exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.

Your doctor may occasionally change your dose to make sure you get the best results.

Moduretic is usually taken once daily, with or without food. If you take chlorthalidone, take it in the morning before 9 AM.

To be sure this medication is helping your condition and not causing harmful effects, your blood pressure will need to be checked on a regular basis.

Drug Interactions

Moduretic can interact with other medications, herbs, or vitamins you might be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, herbs, or vitamins you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Examples of drugs that can cause interactions with Moduretic are listed below.

Interactions with Other Medications

Moduretic can interact with other blood pressure medications, diuretics, lithium, and digoxin.

Interactions with Herbs and Dietary Supplements

Moduretic can interact with herbs and supplements such as garlic, potassium, and salt substitutes that contain potassium.

Mechanism of Action

Moduretic is a diuretic. Diuretics help your body get rid of extra water and salt.

The combination of amiloride and hydrochlorothiazide in Moduretic works by making your kidneys get rid of extra fluid from your body, which lowers blood pressure. It also helps to prevent the absorption of too much salt by your body.


Moduretic is rapidly and completely absorbed from the gastrointestinal tract. The mean peak plasma concentration of amiloride is reached within 1 to 2 hours, and that of hydrochlorothiazide is reached within 3 to 4 hours.


The half-life of Moduretic is about 20 hours.


Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.