Midamor

Midamor is part of the drug class:

• Other potassium sparing agents

Common side effects include:

• headache
• nausea
• loss of appetite
• stomach pain
• gas
• mild skin rash
• diarrhea
• vomiting
• dizziness

This is not a complete list of Midamor side effects. Ask your doctor or pharmacist for more information.

Serious side effects may occur. See "Drug Precautions" section.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of Midamor, salt substitutes containing potassium should be avoided.

Before taking Midamor, tell your doctor about all of your medical conditions. Especially tell your doctor if you:

• have liver disease
• have kidney disease
• have diabetes
• have electrolyte imbalances
• are allergic to any medications
• are pregnant or breastfeeding

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Midamor falls into category B. There are no well-done studies that have been done in humans with Midamor. But in animal studies, pregnant animals were given this medication, and the babies did not show any medical issues related to this medication.

You should not use amiloride if you are allergic to it, or if:

• you have kidney disease or are unable to urinate;

• you have problems with your kidneys caused by diabetes;

• you have high potassium levels (hyperkalemia);

• you take a potassium supplement; or

• you take another potassium-sparing diuretic such Moduretic, spironolactone, or triamterene.

To make sure amiloride is safe for you, tell your doctor if you have:

• diabetes;

• heart disease;

• breathing problems;

• cirrhosis or other liver disease;

• if you are on a low-salt diet; or

• if you are severely ill or debilitated.

Amiloride is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medicine.

It is not known whether amiloride passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.

Midamor is a potassium-conserving (antikaliuretic) drug that possesses weak (compared with thiazide diuretics) natriuretic, diuretic, and antihypertensive activity. These effects have been partially additive to the effects of thiazide diuretics in some clinical studies. When administered with a thiazide or loop diuretic, Midamor has been shown to decrease the enhanced urinary excretion of magnesium which occurs when a thiazide or loop diuretic is used alone. Midamor has potassium-conserving activity in patients receiving kaliuretic-diuretic agents.

Midamor is not an aldosterone antagonist and its effects are seen even in the absence of aldosterone.

Midamor exerts its potassium sparing effect through the inhibition of sodium reabsorption at the distal convoluted tubule, cortical collecting tubule and collecting duct; this decreases the net negative potential of the tubular lumen and reduces both potassium and hydrogen secretion and their subsequent excretion. This mechanism accounts in large part for the potassium sparing action of amiloride.

Midamor usually begins to act within 2 hours after an oral dose. Its effect on electrolyte excretion reaches a peak between 6 and 10 hours and lasts about 24 hours. Peak plasma levels are obtained in 3 to 4 hours and the plasma half-life varies from 6 to 9 hours. Effects on electrolytes increase with single doses of amiloride HCl up to approximately 15 mg.

Amiloride HCl is not metabolized by the liver but is excreted unchanged by the kidneys. About 50 percent of a 20 mg dose of Midamor is excreted in the urine and 40 percent in the stool within 72 hours. Midamor has little effect on glomerular filtration rate or renal blood flow. Because amiloride HCl is not metabolized by the liver, drug accumulation is not anticipated in patients with hepatic dysfunction, but accumulation can occur if the hepatorenal syndrome develops.

Midamor is usually well tolerated and, except for hyperkalemia (serum potassium levels greater than 5.5 mEq per liter see WARNINGS), significant adverse effects have been reported infrequently. Minor adverse reactions were reported relatively frequently (about 20%) but the relationship of many of the reports to amiloride HCl is uncertain and the overall frequency was similar in hydrochlorothiazide treated groups. Nausea/anorexia, abdominal pain, flatulence, and mild skin rash have been reported and probably are related to amiloride. Other adverse experiences that have been reported with amiloride are generally those known to be associated with diuresis, or with the underlying disease being treated.

The adverse reactions for Midamor listed in the following table have been arranged into two groups: (1) incidence greater than one percent; and (2) incidence one percent or less. The incidence for group (1) was determined from clinical studies conducted in the United States (837 patients treated with Midamor). The adverse effects listed in group (2) include reports from the same clinical studies and voluntary reports since marketing. The probability of a causal relationship exists between Midamor and these adverse reactions, some of which have been reported only rarely.

Causal Relationship Unknown

Other reactions have been reported but occurred under circumstances where a causal relationship could not be established. However, in these rarely reported events, that possibility cannot be excluded. Therefore, these observations are listed to serve as alerting information to physicians.

No data are available in regard to overdosage in humans.

The oral LD50 of amiloride hydrochloride (calculated as the base) is 56 mg/kg in mice and 36 to 85 mg/kg in rats, depending on the strain.

It is not known whether the drug is dialyzable.

The most likely signs and symptoms to be expected with overdosage are dehydration and electrolyte imbalance. These can be treated by established procedures. Therapy with Midamor should be discontinued and the patient observed closely. There is no specific antidote. Emesis should be induced or gastric lavage performed. Treatment is symptomatic and supportive. If hyperkalemia occurs, active measures should be taken to reduce the serum potassium levels.