Usage
Citric Acid + Potassium Citrate is prescribed for conditions like kidney stones (specifically calcium oxalate and uric acid stones), renal tubular acidosis, and gout. It is also used to alkalinize urine, which can be beneficial in certain medical situations. It belongs to the pharmacological class of urinary alkalinizers. This combination increases citrate excretion in the urine and raises urine pH, preventing the formation of kidney stones and promoting the excretion of uric acid.
Alternate Names
This medication is sometimes referred to as Potassium Citrate and Citric Acid. Brand names for Citric Acid + Potassium Citrate include Cytra-K, Polycitra-K, and Urocit-K.
How It Works
Pharmacodynamics: Citric acid in this combination binds to calcium in the urine, inhibiting the formation of calcium oxalate stones. Potassium citrate alkalinizes the urine, increasing the solubility of uric acid and preventing the formation of uric acid stones. The alkalinization also inhibits the crystallization of calcium phosphate, further reducing stone formation.
Pharmacokinetics: Citric acid and potassium citrate are readily absorbed from the gastrointestinal tract. Citric acid is metabolized to bicarbonate, contributing to the systemic alkalinizing effect. Potassium citrate is excreted primarily through the kidneys. Both components are eliminated rapidly, requiring frequent dosing to maintain therapeutic effects.
Mode of Action: Citric acid acts by chelating calcium, reducing the free calcium available for stone formation. Potassium citrate is metabolized to bicarbonate, which buffers excess acid in the blood and urine. This alkalinizing effect helps to dissolve existing uric acid stones and prevents the precipitation of new ones.
Elimination Pathways: Citric acid is metabolized and excreted as carbon dioxide and water. Less than 5% is excreted unchanged in urine. Potassium is primarily excreted by the kidneys, with a small amount excreted in the feces.
Dosage
Standard Dosage
Adults:
The standard adult dose is 10 to 30 mEq of potassium citrate three or four times daily. The extended-release form may be given 15-30 mEq twice or three times daily. The total dose should not exceed 100 mEq/day.
Children:
Pediatric dosages must be determined by the physician, ranging from 2 to 4 mEq bicarbonate/kg/day. Adjust dose to maintain target serum CO2.
Special Cases:
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Elderly Patients: Caution is advised; the dose should start at the lower end of the range and adjusted based on renal function and serum potassium.
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Patients with Renal Impairment: Contraindicated in severe renal impairment. Use with caution in mild to moderate renal impairment with dosage adjustments based on creatinine clearance.
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Patients with Hepatic Dysfunction: While specific dosage adjustments are not explicitly stated in the sources, caution is warranted, and monitoring is recommended.
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Patients with Comorbid Conditions: Use with caution in patients with cardiac disease or those on potassium-sparing diuretics.
Clinical Use Cases
Dosage recommendations for specific medical settings should be determined on a patient-specific basis by a physician, especially for intensive care, emergency situations, and during surgical procedures.
Dosage Adjustments
Dose modifications are based on renal function, serum potassium levels, and patient tolerance. In patients with mild to moderate hypocitraturia (urinary citrate > 150 mg/day), the initial dose is typically lower than in those with severe hypocitraturia (urinary citrate < 150 mg/day).
Side Effects
Common Side Effects
Nausea, vomiting, diarrhea, stomach pain, and abdominal discomfort are common side effects.
Rare but Serious Side Effects
Hyperkalemia (high potassium levels), alkalosis, cardiac abnormalities (including arrhythmias), muscle weakness, numbness or tingling, and allergic reactions. Black, tarry stools or vomiting of blood indicate gastrointestinal bleeding.
Long-Term Effects
Long-term use can potentially lead to chronic metabolic alkalosis or electrolyte imbalances. Regular monitoring of serum electrolytes is recommended.
Adverse Drug Reactions (ADR)
Clinically significant ADRs include severe hyperkalemia, cardiac arrest, and severe alkalosis. Immediate intervention is required if these occur.
Contraindications
Severe renal impairment, anuria, hyperkalemia, untreated Addison’s disease, severe myocardial damage, acute dehydration, adynamia episodica hereditaria, and gastrointestinal obstruction.
Drug Interactions
Potassium-sparing diuretics (amiloride, spironolactone, triamterene), ACE inhibitors (lisinopril, enalapril), angiotensin receptor blockers (losartan, valsartan), potassium supplements, and some heart medications (digoxin, quinidine). Antacids containing aluminum, salicylates (aspirin), and nonsteroidal anti-inflammatory drugs can also interact.
Pregnancy and Breastfeeding
Citric Acid + Potassium Citrate is classified as Pregnancy Category C. While animal studies are inconclusive, there are potential fetal risks and it should be used during pregnancy only if the benefits outweigh the risks. Its excretion in breast milk is unknown; caution is advised during breastfeeding.
Drug Profile Summary
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Mechanism of Action: Alkalinizes urine, increases citrate excretion, and inhibits stone formation.
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Side Effects: Nausea, vomiting, diarrhea, abdominal pain, hyperkalemia, alkalosis.
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Contraindications: Severe renal impairment, hyperkalemia, untreated Addison’s disease.
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Drug Interactions: Potassium-sparing diuretics, ACE inhibitors, potassium supplements.
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Pregnancy & Breastfeeding: Category C; use with caution if clearly needed.
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Dosage: Varies depending on condition and individual factors; not to exceed 100 mEq/day.
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Monitoring Parameters: Serum potassium, urine pH, and urinary citrate.
Popular Combinations
Citric Acid + Potassium Citrate is often used alone. However, physicians may combine it with other medications based on the patient’s specific condition, like thiazide diuretics for calcium oxalate stones.
Precautions
- General Precautions: Evaluate renal function and serum potassium before starting and periodically during treatment.
- Specific Populations: Use with caution in pregnancy and breastfeeding.
- Lifestyle Considerations: Advise patients to maintain adequate hydration.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Citric Acid + Potassium Citrate?
A: The standard adult dosage is 10-30 mEq three or four times daily, with a maximum of 100 mEq/day. Pediatric and special population dosages vary and must be determined by a physician.
Q2: What are the common side effects?
A: Nausea, vomiting, diarrhea, and abdominal discomfort.
A: Hyperkalemia (high potassium levels), alkalosis, and allergic reactions.
Q4: Can this medication be used during pregnancy or breastfeeding?
A: It should be used only if clearly needed and under close medical supervision.
Q5: What are the contraindications for this medication?
A: Severe renal impairment, hyperkalemia, and untreated Addison’s disease.
Q6: What other medications interact with this drug?
A: Potassium-sparing diuretics, ACE inhibitors, potassium supplements, and certain heart medications.
Q7: How does this medication work to prevent kidney stones?
A: It alkalinizes urine and increases citrate excretion, inhibiting stone formation.
Q8: What should patients be advised regarding lifestyle considerations while taking this medication?
A: Maintain adequate hydration and discuss dietary potassium intake with their physician.
Q9: Are there any dietary restrictions while taking this medication?
A: Patients may need to avoid high-potassium foods and salt substitutes, depending on their serum potassium levels.
Q10: What monitoring is required during treatment?
A: Regular monitoring of serum potassium, urine pH, and urinary citrate levels is recommended.
