Amiloride and hydrochlorothiazide

FDA label, Teva Pharmaceuticals USA, Inc., oral, effective 2022-12-27. Full label on DailyMed

Patient handout

Looking up MedlinePlus…

From MedlinePlus, U.S. National Library of Medicine

Quoted from the FDA label. Product labels differ by manufacturer and change over time; confirm against the label for the product you are using.

Boxed warning

Like other potassium-conserving diuretic combinations, amiloride and hydrochlorothiazide may cause hyperkalemia (serum potassium levels greater than 5.5 mEq per liter). In patients without renal impairment or diabetes mellitus, the risk of hyperkalemia with this combination product is about 1 to 2 percent. This risk is higher in patients with renal impairment or diabetes mellitus (even without recognized diabetic nephropathy).

Since hyperkalemia, if uncorrected, is potentially fatal, it is essential to monitor serum potassium levels carefully in any patient receiving amiloride hydrochloride and hydrochlorothiazide, particularly when it is first introduced, at the time of dosage adjustments, and during any illness that could affect renal function.

Thiazide Diuretic

Dosing in kidney impairment

Impaired Renal Function Anuria, acute or chronic renal insufficiency, and evidence of diabetic nephropathy are contraindications to the use of amiloride hydrochloride and hydrochlorothiazide. Patients with evidence of renal function impairment (blood urea nitrogen [BUN] levels over 30 mg per 100 mL or serum creatinine levels over 1.5 mg per 100 mL) or diabetes mellitus should not receive the drug without careful, frequent and continuing monitoring of serum electrolytes, creatinine, and BUN levels.

Potassium retention associated with the use of an antikaliuretic agent is accentuated in the presence of renal impairment and may result in the rapid development of hyperkalemia. Hypersensitivity Amiloride hydrochloride and hydrochlorothiazide tablets is contraindicated in patients who are hypersensitive to this product, or to other sulfonamide-derived drugs.

WARNINGS Hyperkalemia Like other potassium-conserving diuretic combinations, amiloride and hydrochlorothiazide may cause hyperkalemia (serum potassium levels greater than 5.5 mEq per liter). In patients without renal impairment or diabetes mellitus, the risk of hyperkalemia with this combination product is about 1 to 2 percent.

This risk is higher in patients with renal impairment or diabetes mellitus (even without recognized diabetic nephropathy). Since hyperkalemia, if uncorrected, is potentially fatal, it is essential to monitor serum potassium levels carefully in any patient receiving amiloride hydrochloride and hydrochlorothiazide, particularly when it is first introduced, at the time of dosage adjustments, and during any illness that could affect renal function.

Therefore, amiloride and hydrochlorothiazide should be avoided, if possible, in diabetic patients and, if it is used, serum electrolytes and renal function must be monitored frequently. Amiloride and hydrochlorothiazide should be discontinued at least three days before glucose tolerance testing. Metabolic or Respiratory Acidosis Antikaliuretic therapy should be instituted only with caution in severely ill patients in whom respiratory or metabolic acidosis may occur, such as patients with cardiopulmonary disease or poorly controlled diabetes.

Drug interactions

Check amiloride and hydrochlorothiazide against a medication list
Label text (4 paragraphs)

Drug Interactions In some patients, the administration of a non-steroidal anti-inflammatory agent can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics. Therefore, when amiloride and hydrochlorothiazide plus non-steroidal anti-inflammatory agents are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained.

Since indomethacin and potassium-sparing diuretics, including this product, may each be associated with increased serum potassium levels, the potential effects on potassium kinetics and renal function should be considered when these agents are administered concurrently. Amiloride HCl When amiloride HCl is administered concomitantly with an angiotensin-converting enzyme inhibitor, cyclosporine or tacrolimus, the risk of hyperkalemia may be increased. Therefore, if concomitant use of these agents is indicated because of demonstrated hypokalemia, they should be used with caution and with frequent monitoring of serum potassium (see WARNINGS ).

Hydrochlorothiazide When given concurrently the following drugs may interact with thiazide diuretics. Alcohol, Barbiturates, or Narcotics Potentiation of orthostatic hypotension may occur. Antidiabetic Drugs (Oral Agents and Insulin) Dosage adjustment of the antidiabetic drug may be required. Other Antihypertensive Drugs Additive effect or potentiation. Cholestyramine and Colestipol Resins Absorption of hydrochlorothiazide is impaired in the presence of anionic exchange resins. Single doses of cholestyramine and colestipol resins bind the hydrochlorothiazide and reduce its absorption from the gastrointestinal tract by up to 85 and 43 percent, respectively.

Corticosteroids, ACTH Intensified electrolyte depletion, particularly hypokalemia. Pressor Amines (e.g., norepinephrine) Possible decreased response to pressor amines but not sufficient to preclude their use. Skeletal Muscle Relaxants, Nondepolarizing (e.g., tubocurarine) Possible increased responsiveness to the muscle relaxant. Lithium Generally should not be given with diuretics. Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity. Refer to the package insert for lithium preparations before use of such preparations with this combination product.

Supplement interactions

Dietary supplement interactions

6 noted
  • Vitamin DThiazide diuretics
    Thiazide diuretics (e.g., Hygroton, Lozol, and Microzide) decrease urinary calcium excretion. The combination of these diuretics with vitamin D supplements (which increase intestinal calcium absorption) might lead to hypercalcemia, especially among older adults and individuals with compromised renal function or hyperparathyroidism.
    Fact sheet, updated Jun 27, 2025
  • MagnesiumDiuretics
    Chronic treatment with loop diuretics, such as furosemide (Lasix) and bumetanide (Bumex), and thiazide diuretics, such as hydrochlorothiazide (Aquazide H) and ethacrynic acid (Edecrin), can increase the loss of magnesium in urine and lead to magnesium depletion. In contrast, potassium-sparing diuretics, such as amiloride (Midamor) and spironolactone (Aldactone), reduce magnesium excretion.
    Fact sheet, updated Jan 6, 2026
  • ZincDiuretics
    Thiazide diuretics, such as chlorthalidone (e.g., Hygroton, Thalitone) and hydrochlorothiazide (e.g., Esidrix, HydroDIURIL), increase zinc excretion in the urine. This increased excretion, in turn, decreases serum zinc concentrations.
    Fact sheet, updated Jan 6, 2026
  • PotassiumPotassium-sparing diuretics
    Potassium-sparing diuretics, such as amiloride (Midamor) and spironolactone (Aldactone), reduce the excretion of potassium in the urine and can cause hyperkalemia. Experts recommend monitoring potassium status in people taking these medications, especially if they have impaired kidney function or other risk factors for hyperkalemia.
    Fact sheet, updated Jun 2, 2022
  • PotassiumLoop and thiazide diuretics
    Treatment with loop diuretics, such as furosemide (Lasix) and bumetanide (Bumex), and thiazide diuretics, such as chlorothiazide (Diuril) and metolazone (Zaroxolyn), increases urinary potassium excretion and can lead to hypokalemia. Experts recommend monitoring potassium status in people taking these medications and initiating potassium supplementation if warranted.
    Fact sheet, updated Jun 2, 2022
  • IodinePotassium-sparing diuretics
    Taking potassium iodide with potassium-sparing diuretics, such as spironolactone (Aldactone) and amiloride (Midamor), can increase the risk of hyperkalemia.
    Fact sheet, updated Nov 5, 2024

Contraindications

Hyperkalemia Amiloride hydrochloride and hydrochlorothiazide tablets should not be used in the presence of elevated serum potassium levels (greater than 5.5 mEq per liter). Antikaliuretic Therapy or Potassium Supplementation Amiloride hydrochloride and hydrochlorothiazide should not be given to patients receiving other potassium-conserving agents, such as spironolactone or triamterene. Potassium supplementation in the form of medication, potassium-containing salt substitutes or a potassium-rich diet should not be used with this product except in severe and/or refractory cases of hypokalemia. Such concomitant therapy can be associated with rapid increases in serum potassium levels.

If potassium supplementation is used, careful monitoring of the serum potassium level is necessary. Impaired Renal Function Anuria, acute or chronic renal insufficiency, and evidence of diabetic nephropathy are contraindications to the use of amiloride hydrochloride and hydrochlorothiazide. Patients with evidence of renal function impairment (blood urea nitrogen [BUN] levels over 30 mg per 100 mL or serum creatinine levels over 1.5 mg per 100 mL) or diabetes mellitus should not receive the drug without careful, frequent and continuing monitoring of serum electrolytes, creatinine, and BUN levels.

Potassium retention associated with the use of an antikaliuretic agent is accentuated in the presence of renal impairment and may result in the rapid development of hyperkalemia. Hypersensitivity Amiloride hydrochloride and hydrochlorothiazide tablets is contraindicated in patients who are hypersensitive to this product, or to other sulfonamide-derived drugs.

Safety data

Reported adverse events (FAERS)

Loading
Source: FDA Adverse Event Reporting System via openFDA

Liver injury (LiverTox)

LiverTox has no chapter for amiloride and hydrochlorothiazide. Check the label's hepatic warnings.

Pregnancy and lactation

Pregnancy

Pregnancy

Lactation

Nursing Mothers Studies in rats have shown that amiloride is excreted in milk in concentrations higher than those found in blood, but it is not known whether amiloride HCl is excreted in human milk. However, thiazides appear in breast milk. Because of the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

For breastfeeding, also see LactMed (National Library of Medicine), which summarizes milk levels and infant effects.

Supply and cost

Drug shortage status

Loading

Recalls (last 24 months)

Loading

Therapeutic equivalence (Orange Book)

Loading

Price ladder

Not the price at the counter
Loading

These are not what a patient pays at the pharmacy counter. They are what pharmacies, health plans, and government buyers pay, before manufacturer rebates. A patient's cost depends on their insurance (copay, coinsurance, or deductible) or the pharmacy's cash price.

Products and NDCs

Loading

Recruiting clinical trials

Loading