Usage
Amiloride + Furosemide is prescribed for the treatment of hypertension (high blood pressure) and edema (fluid retention) associated with conditions like heart failure. It belongs to the pharmacological classification of diuretics, specifically a combination of a loop diuretic (furosemide) and a potassium-sparing diuretic (amiloride). The combination works synergistically to eliminate excess fluid while minimizing potassium loss.
Alternate Names
Co-amilofruse is the British Approved Name (BAN). Brand names include Frumil and Frumil LS. Amifru, Amimide, Exna-K, and Lasiride are also marketed in India.
How It Works
Pharmacodynamics: Furosemide inhibits sodium, potassium, and chloride reabsorption in the ascending loop of Henle, promoting increased urine output. Amiloride blocks sodium channels in the distal convoluted tubule, reducing sodium reabsorption and potassium excretion. The combined action leads to enhanced diuresis with potassium conservation.
Pharmacokinetics: Furosemide is readily absorbed orally with a bioavailability of approximately 65%. It is highly protein-bound and primarily excreted unchanged in the urine. Amiloride is also absorbed orally and partially metabolized in the liver. It is excreted primarily through the kidneys.
Mechanism of Action: Furosemide inhibits the Na-K-2Cl cotransporter in the loop of Henle, preventing the reabsorption of these electrolytes. Amiloride blocks epithelial sodium channels in the distal tubule, reducing sodium entry and subsequent potassium secretion.
Elimination Pathways: Primarily renal excretion for both drugs.
Dosage
Standard Dosage
Adults:
The initial dose is typically one tablet (40 mg furosemide and 5 mg amiloride hydrochloride) taken orally each morning. The dosage may be increased to a maximum of two tablets daily, taken as separate doses (one in the morning and one at noon). The maximum daily dose of amiloride should not exceed 20 mg.
Children:
Use is generally not recommended for children under 18. Some off-label use exists, and the dosage should be determined by a physician based on the child’s weight and condition.
Special Cases:
- Elderly Patients: Start with a lower dose and titrate upwards as needed, monitoring renal function closely.
- Patients with Renal Impairment: Dose reduction is necessary; use is not recommended if creatinine clearance is below 30 mL/min.
- Patients with Hepatic Dysfunction: Caution advised; dosage adjustments may be needed.
- Patients with Comorbid Conditions: Close monitoring of electrolyte levels and blood glucose in diabetic patients is crucial.
Clinical Use Cases
The drug is primarily indicated for hypertension and edema management in heart failure. Its use in settings like intubation, surgical procedures, mechanical ventilation, and the ICU is not standard practice but might be considered under special circumstances based on fluid management needs. The dosage in emergency situations should be determined based on the individual patient’s condition.
Dosage Adjustments
Dose adjustments are necessary based on renal function, hepatic function, electrolyte levels, and concurrent medications. Genetic polymorphisms affecting drug metabolism should be considered when individualizing dosage.
Side Effects
Common Side Effects:
Dizziness, lightheadedness, headache, blurred vision, nausea, vomiting, loss of appetite, stomach/abdominal pain, gas, diarrhea, fatigue, and electrolyte imbalances.
Rare but Serious Side Effects:
Severe hypotension, hyperkalemia (high potassium), hyponatremia (low sodium), dehydration, and allergic reactions.
Long-Term Effects:
Electrolyte disturbances, gout, and increased blood sugar levels.
Adverse Drug Reactions (ADR):
Severe allergic reactions (anaphylaxis), Stevens-Johnson syndrome, and toxic epidermal necrolysis.
Contraindications
Hyperkalemia, severe hypokalaemia, anuria, severe renal failure, hepatic encephalopathy, concomitant potassium supplements, pregnancy, breastfeeding, and hypersensitivity to the drug’s components.
Drug Interactions
Amiloride + Furosemide can interact with various drugs, including other diuretics, NSAIDs, ACE inhibitors, lithium, digoxin, antihypertensives, corticosteroids, and certain antibiotics. Interactions with OTC drugs, supplements (like potassium), alcohol, and foods (e.g., grapefruit juice) are also possible.
Pregnancy and Breastfeeding
This combination is contraindicated in pregnancy and breastfeeding due to the potential risks to the fetus and neonate.
Drug Profile Summary
- Mechanism of Action: Loop diuretic and potassium-sparing diuretic combination that increases urine output while preserving potassium.
- Side Effects: Dizziness, headache, electrolyte imbalances, gastrointestinal upset.
- Contraindications: Hyperkalemia, anuria, renal failure, pregnancy, breastfeeding.
- Drug Interactions: Numerous drug interactions; caution advised with NSAIDs, ACE inhibitors, lithium, and digoxin.
- Pregnancy & Breastfeeding: Contraindicated.
- Dosage: Initial dose: one tablet daily; maximum: two tablets daily.
- Monitoring Parameters: Blood pressure, electrolytes (potassium, sodium, magnesium, chloride), renal function, blood glucose.
Popular Combinations
Amiloride + Furosemide is itself a popular combination. It is not typically combined with other diuretics.
Precautions
- General Precautions: Monitor electrolytes, renal function, and blood pressure.
- Specific Populations: Not recommended for children or during pregnancy and breastfeeding. Use with caution in elderly patients and those with hepatic or renal impairment.
- Lifestyle Considerations: Avoid alcohol as it can exacerbate hypotension.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Amiloride + Furosemide?
A: The initial adult dose is one tablet (40mg furosemide/5mg amiloride) daily. This can be increased to a maximum of two tablets per day, taken as separate doses.
Q2: What are the common side effects of this drug?
A: Common side effects include dizziness, headache, nausea, and electrolyte imbalances.
Q3: Can this medication be used during pregnancy?
A: No, Amiloride + Furosemide is contraindicated during pregnancy and breastfeeding.
Q4: How does this medication affect potassium levels?
A: The amiloride component helps to conserve potassium, counteracting the potassium-wasting effect of furosemide.
Q5: What are the major drug interactions I should be aware of?
A: Significant interactions can occur with NSAIDs, ACE inhibitors, digoxin, and lithium.
Q6: What should I monitor in patients taking this medication?
A: Monitor blood pressure, electrolyte levels (particularly potassium), renal function, and blood glucose.
Q7: What should I do if a patient experiences dizziness while taking this medication?
A: Advise the patient to sit or lie down. If dizziness persists or is severe, re-evaluate the dosage and consider other causes.
Q8: Can patients with renal impairment take this medication?
A: Dosage adjustments are required in patients with renal impairment, and the medication is contraindicated in severe renal failure.
Q9. Is this medicine safe to take with alcohol?
A: Alcohol can exacerbate the hypotensive effects of this medication and should be avoided or consumed in moderation.
