Amiloride 5mg Tablets
WARNING: Sometimes, this drug may raise potassium levels in the blood. This can be deadly if it is not treated. The risk is highest in people with diabetes, kidney disease, severe illness, and in older adults. Your doctor will follow you closely to change the dose if needed. @ COMMON USES: It is used to treat or prevent low potassium levels.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Potassium-sparing diuretic
Pharmacologic Class
Epithelial sodium channel (ENaC) inhibitor
Pregnancy Category
B
FDA Approved
Aug 1976
DEA Schedule
Not Controlled
Overview
What is this medicine?
Amiloride is a 'water pill' (diuretic) that helps your body get rid of extra salt and water, which can lower blood pressure and reduce swelling. Unlike some other water pills, amiloride helps your body keep potassium, which is an important mineral.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take this medication with food as directed. Continue taking the medication as prescribed by your doctor or healthcare provider, even if you start to feel better.
Storing and Disposing of Your Medication
Store this medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a secure place, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of medications, consult your pharmacist. You may also want to check if there are drug take-back programs available in your area.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take this medication with food as directed. Continue taking the medication as prescribed by your doctor or healthcare provider, even if you start to feel better.
Storing and Disposing of Your Medication
Store this medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a secure place, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of medications, consult your pharmacist. You may also want to check if there are drug take-back programs available in your area.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Do not use salt substitutes or potassium supplements unless specifically instructed by your doctor, as this can lead to dangerously high potassium levels.
- Avoid foods very high in potassium (e.g., bananas, oranges, potatoes, leafy greens) in large quantities, especially if you have kidney problems or are taking other medications that increase potassium.
- Stay hydrated as advised by your doctor, especially in hot weather or during exercise, to prevent dehydration.
- Monitor your blood pressure regularly at home if advised by your doctor.
- Report any signs of high potassium (muscle weakness, fatigue, slow or irregular heartbeat) or dehydration (dizziness, dry mouth) to your doctor immediately.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 5 mg once daily. May be increased to 10 mg once daily if necessary. Max: 20 mg daily.
Dose Range:
5 - 20 mg
Condition-Specific Dosing:
hypertension:
Initial: 5 mg once daily. Maintenance: 5-10 mg once daily.
congestiveHeartFailure:
Initial: 5 mg once daily. Maintenance: 5-10 mg once daily, often in combination with loop diuretics.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established (limited data, use with caution, 0.625 mg/kg/day or 20 mg/m2/day has been reported in some cases, but generally not recommended)
Adolescent:
Not established (limited data, use with caution)
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment, but monitor electrolytes and renal function closely.
Moderate:
Use with caution. Consider reduced dose (e.g., 2.5 mg daily) and frequent monitoring of serum potassium and renal function. Avoid if CrCl < 50 mL/min.
Severe:
Contraindicated (CrCl < 30 mL/min) due to high risk of hyperkalemia.
Dialysis:
Contraindicated. Amiloride is not significantly removed by hemodialysis.
Hepatic Impairment:
Mild:
No specific adjustment, but monitor for signs of hepatic encephalopathy.
Moderate:
Use with caution. Increased risk of hepatic encephalopathy in patients with severe liver disease.
Severe:
Use with extreme caution or avoid. Increased risk of hepatic encephalopathy.
Pharmacology
Mechanism of Action
Amiloride is a potassium-sparing diuretic that acts directly on the epithelial sodium channels (ENaC) in the luminal membrane of the collecting duct and, to a lesser extent, the distal convoluted tubule. By inhibiting ENaC, it reduces sodium reabsorption and, consequently, potassium and hydrogen ion secretion. This leads to increased excretion of sodium and water, while conserving potassium and hydrogen ions.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 50%
Tmax:
3-6 hours
FoodEffect:
Absorption is not significantly affected by food.
Distribution:
Vd:
Approximately 3.5 L/kg
ProteinBinding:
Approximately 23%
CnssPenetration:
Limited
Elimination:
HalfLife:
6-9 hours (prolonged in renal impairment)
Clearance:
Not readily available (primarily renal excretion)
ExcretionRoute:
Renal (approximately 50% unchanged in urine), Fecal (approximately 40% unchanged)
Unchanged:
Approximately 50% (urine), 40% (feces)
Pharmacodynamics
OnsetOfAction:
2 hours
PeakEffect:
6-10 hours
DurationOfAction:
24 hours
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high potassium levels, including:
+ Abnormal heartbeat
+ Confusion
+ Weakness, lightheadedness, or dizziness
+ Feeling like passing out
+ Numbness or tingling
+ Shortness of breath
Slow heartbeat
Muscle pain or weakness
Other Possible Side Effects
Most people taking this medication will not experience side effects, or they may be mild. However, if you notice any of the following side effects, or if they bother you or do not go away, contact your doctor:
Headache
Diarrhea
Stomach pain
Upset stomach
Vomiting
Decreased appetite
* Gas
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, contact your doctor for medical advice. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high potassium levels, including:
+ Abnormal heartbeat
+ Confusion
+ Weakness, lightheadedness, or dizziness
+ Feeling like passing out
+ Numbness or tingling
+ Shortness of breath
Slow heartbeat
Muscle pain or weakness
Other Possible Side Effects
Most people taking this medication will not experience side effects, or they may be mild. However, if you notice any of the following side effects, or if they bother you or do not go away, contact your doctor:
Headache
Diarrhea
Stomach pain
Upset stomach
Vomiting
Decreased appetite
* Gas
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, contact your doctor for medical advice. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Muscle weakness or cramps
- Unusual tiredness or fatigue
- Numbness or tingling sensations (paresthesias)
- Slow or irregular heartbeat
- Dizziness or lightheadedness (especially when standing up)
- Excessive thirst or dry mouth
- Decreased urination
- Confusion or disorientation
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
Certain health conditions, including:
+ Diabetes
+ High potassium levels
+ Kidney disease
+ Urination difficulties
Your diet, particularly if it is rich in potassium
Any medications you are currently taking, including:
+ Spironolactone
+ Triamterene
+ Potassium-containing drugs
+ Salt substitutes
+ Lithium
* All other medications, supplements, and vitamins you are taking, whether prescription or over-the-counter (OTC), as well as any natural products
This list is not exhaustive, and it is crucial to discuss all your medications and health conditions with your doctor and pharmacist to ensure safe use. Never start, stop, or adjust the dosage of any medication without first consulting your doctor to confirm it is safe to do so in conjunction with this medication.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
Certain health conditions, including:
+ Diabetes
+ High potassium levels
+ Kidney disease
+ Urination difficulties
Your diet, particularly if it is rich in potassium
Any medications you are currently taking, including:
+ Spironolactone
+ Triamterene
+ Potassium-containing drugs
+ Salt substitutes
+ Lithium
* All other medications, supplements, and vitamins you are taking, whether prescription or over-the-counter (OTC), as well as any natural products
This list is not exhaustive, and it is crucial to discuss all your medications and health conditions with your doctor and pharmacist to ensure safe use. Never start, stop, or adjust the dosage of any medication without first consulting your doctor to confirm it is safe to do so in conjunction with this medication.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Regularly monitor your blood pressure as directed by your healthcare provider. Additionally, have your blood work checked as scheduled by your doctor, and discuss the results with them.
Be aware that this medication may interfere with certain laboratory tests. Therefore, it is crucial to notify all your healthcare providers and laboratory personnel that you are taking this drug.
If you are following a low-salt or salt-free diet, consult with your doctor. Avoid using salt substitutes that contain potassium, as well as potassium-sparing diuretics and potassium products, unless otherwise advised by your doctor. It is also recommended that you discuss alcohol consumption with your doctor before drinking.
If you are 65 years or older, exercise caution when taking this medication, as you may be more susceptible to side effects.
If you are pregnant, planning to become pregnant, or breastfeeding, inform your doctor. It is necessary to discuss the potential benefits and risks of this medication to both you and your baby.
Regularly monitor your blood pressure as directed by your healthcare provider. Additionally, have your blood work checked as scheduled by your doctor, and discuss the results with them.
Be aware that this medication may interfere with certain laboratory tests. Therefore, it is crucial to notify all your healthcare providers and laboratory personnel that you are taking this drug.
If you are following a low-salt or salt-free diet, consult with your doctor. Avoid using salt substitutes that contain potassium, as well as potassium-sparing diuretics and potassium products, unless otherwise advised by your doctor. It is also recommended that you discuss alcohol consumption with your doctor before drinking.
If you are 65 years or older, exercise caution when taking this medication, as you may be more susceptible to side effects.
If you are pregnant, planning to become pregnant, or breastfeeding, inform your doctor. It is necessary to discuss the potential benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Dehydration
- Electrolyte imbalances (especially hyperkalemia, hyponatremia)
- Hypotension (low blood pressure)
- Cardiac arrhythmias (due to hyperkalemia)
- Muscle weakness, paralysis
- Renal failure
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is supportive and symptomatic, focusing on correcting fluid and electrolyte imbalances, particularly hyperkalemia. Gastric lavage or activated charcoal may be considered if ingestion is recent. Hemodialysis is not effective for removing amiloride.
Drug Interactions
Contraindicated Interactions
- Potassium supplements (oral or IV)
- Potassium-containing salt substitutes
- Other potassium-sparing diuretics (e.g., spironolactone, eplerenone, triamterene)
- Patients with serum potassium > 5.5 mEq/L
- Patients with anuria, acute renal failure, or progressive severe renal disease
Major Interactions
- ACE inhibitors (e.g., enalapril, lisinopril): Increased risk of severe hyperkalemia.
- Angiotensin Receptor Blockers (ARBs) (e.g., valsartan, losartan): Increased risk of severe hyperkalemia.
- NSAIDs (e.g., ibuprofen, naproxen): May reduce diuretic and antihypertensive effects of amiloride and increase risk of hyperkalemia and renal dysfunction.
- Cyclosporine, Tacrolimus: Increased risk of severe hyperkalemia.
- Trimethoprim/Sulfamethoxazole: Increased risk of hyperkalemia.
Moderate Interactions
- Lithium: Amiloride may reduce renal clearance of lithium, leading to increased serum lithium levels and potential toxicity. Monitor lithium levels.
- Digoxin: While amiloride helps prevent hypokalemia (which can predispose to digoxin toxicity), electrolyte imbalances can still affect digoxin levels or toxicity.
- Other antihypertensive agents: Additive hypotensive effects.
- Alcohol, barbiturates, narcotics: May potentiate orthostatic hypotension.
Minor Interactions
- Corticosteroids, ACTH: May diminish diuretic effect due to sodium and water retention.
Monitoring
Baseline Monitoring
Serum Potassium (K+)
Rationale: To establish baseline and identify pre-existing hyperkalemia, which is a contraindication.
Timing: Prior to initiation of therapy.
Serum Sodium (Na+)
Rationale: To establish baseline and monitor for hyponatremia.
Timing: Prior to initiation of therapy.
Renal Function (BUN, Serum Creatinine, eGFR)
Rationale: To assess kidney function, as amiloride is renally excreted and its use is contraindicated or requires caution in renal impairment.
Timing: Prior to initiation of therapy.
Blood Pressure (BP)
Rationale: To establish baseline and monitor therapeutic effect.
Timing: Prior to initiation of therapy.
Routine Monitoring
Serum Potassium (K+)
Frequency: Within 1 week of initiation or dose change, then monthly for the first few months, then every 3-6 months, or more frequently if risk factors for hyperkalemia are present (e.g., renal impairment, concomitant ACEI/ARB use).
Target: 3.5-5.0 mEq/L
Action Threshold: Hold dose or discontinue if K+ > 5.5 mEq/L. Investigate cause and manage hyperkalemia.
Serum Sodium (Na+)
Frequency: Periodically, especially if signs of fluid imbalance or concomitant diuretic use.
Target: 135-145 mEq/L
Action Threshold: Investigate and manage if Na+ < 130 mEq/L or symptomatic hyponatremia.
Renal Function (BUN, Serum Creatinine, eGFR)
Frequency: Within 1 week of initiation or dose change, then every 3-6 months, or more frequently if risk factors for renal impairment are present.
Target: Stable within patient's baseline range.
Action Threshold: Significant increase in BUN/Cr or decrease in eGFR warrants dose adjustment or discontinuation.
Blood Pressure (BP)
Frequency: Regularly, as clinically indicated.
Target: Individualized based on treatment goals (e.g., <130/80 mmHg for most adults).
Action Threshold: Persistent hypotension or uncontrolled hypertension requires evaluation.
Symptom Monitoring
- Signs of hyperkalemia (e.g., muscle weakness, fatigue, paresthesias, bradycardia, irregular heartbeat)
- Signs of hyponatremia (e.g., headache, nausea, confusion, lethargy, seizures)
- Signs of dehydration/volume depletion (e.g., dizziness, lightheadedness, dry mouth, decreased urine output)
- Signs of hepatic encephalopathy (in patients with liver disease: confusion, disorientation, asterixis)
Special Patient Groups
Pregnancy
Amiloride is Pregnancy Category B. Animal studies have not shown harm to the fetus, but there are no adequate and well-controlled studies in pregnant women. Use during pregnancy only if clearly needed.
Trimester-Specific Risks:
First Trimester:
No specific increased risk of malformations identified in animal studies.
Second Trimester:
No specific increased risk identified.
Third Trimester:
Diuretics are generally not recommended for routine use in healthy pregnant women with mild edema, as they may decrease placental perfusion. Use only for specific indications (e.g., cardiac disease).
Lactation
Amiloride is excreted in breast milk in animal studies, but human data are lacking. Due to the potential for serious adverse reactions in the nursing infant (e.g., electrolyte imbalance), a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother. Lactation risk is L3 (Moderate risk).
Infant Risk:
Potential for electrolyte disturbances (e.g., hyperkalemia, hyponatremia) in the infant. Monitor infant for signs of dehydration or electrolyte imbalance.
Pediatric Use
Safety and effectiveness in pediatric patients have not been established. Use is generally not recommended due to limited data and potential for serious electrolyte imbalances, especially hyperkalemia. If used, extreme caution and close monitoring are required.
Geriatric Use
Elderly patients are at increased risk for adverse effects, particularly hyperkalemia and dehydration, due to age-related decline in renal function and potential for polypharmacy. Initiate therapy with lower doses and monitor serum electrolytes and renal function more frequently.
Clinical Information
Clinical Pearls
- Amiloride is primarily used to counteract potassium loss caused by other diuretics (e.g., thiazides, loop diuretics) or in conditions where potassium conservation is desired.
- Always check serum potassium and renal function before initiating amiloride and regularly during therapy.
- Educate patients thoroughly about the risk of hyperkalemia and the importance of avoiding potassium supplements and salt substitutes.
- It is often used in combination with hydrochlorothiazide (e.g., Moduretic) to provide both diuretic and potassium-sparing effects.
- While generally well-tolerated, the most significant adverse effect is hyperkalemia, especially in patients with renal impairment or those taking other potassium-raising medications.
Alternative Therapies
- Spironolactone (aldosterone antagonist, potassium-sparing diuretic)
- Eplerenone (selective aldosterone antagonist, potassium-sparing diuretic)
- Triamterene (another ENaC inhibitor, potassium-sparing diuretic)
- Thiazide diuretics (e.g., hydrochlorothiazide, chlorthalidone) - often used in combination with potassium-sparing diuretics
- Loop diuretics (e.g., furosemide, bumetanide) - often used in combination with potassium-sparing diuretics
Cost & Coverage
Average Cost:
$10 - $30 per 30 tablets (5mg generic)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (preferred generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.