Usage
Citric acid, in combination with its salts (sodium citrate, potassium citrate), is primarily used as a urinary alkalinizer to treat metabolic acidosis, prevent kidney stones (uric acid and cystine), and manage acidosis in renal tubular disorders. It is also used to increase the pH of urine and blood. It is not an endothelin receptor antagonist. Citric acid on its own has additional uses such as a flavoring agent and an antioxidant synergist.
Alternate Names
Citric acid is also referred to as 2-hydroxy-1,2,3-propanetricarboxylic acid. Combination preparations include citric acid with sodium citrate and/or potassium citrate. These combinations are often referred to as “oral citrates,” and several brand names exist, such as Bicitra, Cytra-2, Liqui-Dual Citra, Oracit, Polycitra, and Virtrate-3.
How It Works
Pharmacodynamics: Citrate salts primarily act as alkalinizing agents. They are metabolized in the liver (≥95%) to bicarbonate, which increases blood and urinary pH.
Pharmacokinetics:
- Absorption: Readily absorbed from the gastrointestinal tract.
- Metabolism: Extensively metabolized in the liver by oxidation to bicarbonate.
- Elimination: Less than 5% is excreted unchanged in urine.
Dosage
Standard Dosage
Adults:
For urinary alkalinization: 10 to 30 mL of the solution diluted in water, four times a day after meals and at bedtime, or as directed by a physician. For other specific conditions, 1-2 g of sodium citrate every 2-4 hours may be administered.
Children:
Dosage must be individualized based on the child’s age, weight, and clinical condition. For urinary alkalinization, typical doses range from 5-15 mL of solution, diluted in water, after meals and at bedtime, or as directed by a physician.
Special Cases:
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Elderly Patients: Dosages should be adjusted based on kidney function and overall health status. Lower dosages may be required.
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Patients with Renal Impairment: Use with caution. Contraindicated in severe renal impairment. Dosage must be adjusted based on the degree of impairment.
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Patients with Hepatic Dysfunction: Use with caution. Citrate metabolism may be impaired.
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Patients with Comorbid Conditions: Use with caution in cardiovascular disease, edema, hypertension, and other relevant comorbid conditions.
Clinical Use Cases
The available sources primarily focus on using citric acid/citrate combinations for urinary alkalinization. Therefore, no specific dosage information is available for intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations.
Dosage Adjustments
Dose adjustments are needed for patients with renal or hepatic impairment. Electrolyte and acid-base balance should be closely monitored, particularly in these patients. If using potassium-containing formulations, caution should be exercised in patients receiving therapies that affect potassium levels.
Side Effects
Common Side Effects
Nausea, vomiting, diarrhea (particularly with frequent administration or high doses).
Rare but Serious Side Effects
Allergic reactions (hives, difficulty breathing, swelling), metabolic alkalosis (with excessive intake), hypocalcemia (if using citrate for anticoagulation).
Long-Term Effects
Erosion of tooth enamel with frequent or prolonged use.
Adverse Drug Reactions (ADR)
Hyperkalemia (with potassium-containing preparations), metabolic disturbances, aluminum toxicity (increased absorption with oral citrates), tetany (due to hypocalcemia), cardiac arrhythmias (due to electrolyte imbalances).
Contraindications
Severe renal impairment, untreated Addison’s disease, severe myocardial damage, hyperkalemia (with potassium-containing formulations), anuria, severe dehydration, adynamia episodica hereditaria, heat cramps.
Drug Interactions
Aluminum-containing antacids (increased aluminum absorption), potassium-sparing diuretics, ACE inhibitors (increased risk of hyperkalemia), digitalis glycosides (altered potassium levels may affect digitalis activity).
Pregnancy and Breastfeeding
Consult with a physician before using citric acid/citrate combinations during pregnancy or breastfeeding. The safety profile during these periods needs careful consideration.
Drug Profile Summary
- Mechanism of Action: Alkalinizes urine and blood by being metabolized to bicarbonate.
- Side Effects: Nausea, vomiting, diarrhea, allergic reactions, metabolic disturbances, tooth erosion.
- Contraindications: Severe renal impairment, untreated Addison’s disease, hyperkalemia, anuria.
- Drug Interactions: Aluminum antacids, potassium-sparing diuretics, ACE inhibitors, digitalis.
- Pregnancy & Breastfeeding: Consult a physician.
- Dosage: Adult: 10-30 mL solution four times daily, diluted in water. Pediatric: individualized.
- Monitoring Parameters: Serum electrolytes, arterial blood gas, urine pH.
Popular Combinations
Citric acid is frequently combined with sodium and/or potassium citrate for urinary alkalinization.
Precautions
Monitor electrolyte balance and acid-base status, especially in patients with renal or hepatic disease, heart failure, or hypertension. Potassium-containing preparations should be used cautiously in patients at risk of hyperkalemia. Prolonged or excessive use may cause tooth erosion.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Citric Acid/citrate combinations for urinary alkalinization?
A: Adults: 10-30 mL of the solution diluted in water, four times daily after meals and at bedtime. Children: Dosage must be determined by the physician.
Q2: How does citric acid help prevent kidney stones?
A: Citric acid inhibits crystallization and stone formation, primarily by binding to calcium, thereby reducing the saturation of calcium oxalate and calcium phosphate, and increasing urine citrate levels, which inhibits stone formation.
Q3: Can citric acid be used during pregnancy?
A: Consult a physician before using citric acid/citrate combinations during pregnancy, as its safety profile during this period necessitates careful consideration based on individual risk factors.
Q4: What are the common side effects of citric acid/citrate?
A: Nausea, vomiting, and diarrhea are common side effects, particularly with high doses or frequent administration.
Q5: What are the contraindications for citric acid/citrate use?
A: Contraindications include severe renal impairment, untreated Addison’s disease, severe myocardial damage, and hyperkalemia (if using potassium citrate).
Q6: Does citric acid interact with other medications?
A: Yes, it can interact with aluminum-containing antacids, potassium-sparing diuretics, ACE inhibitors, and digitalis glycosides.
Q7: How should citric acid/citrate solutions be administered?
A: Dilute the prescribed dose in a full glass of water or juice before taking it orally. It’s typically taken after meals to reduce gastrointestinal side effects.
Q8: What should patients be monitored for when taking citric acid/citrate?
A: Monitor serum electrolytes, arterial blood gases, and urine pH, especially in patients with renal impairment.
A: Yes, Citric acid, specifically in the form of citrate salts like sodium citrate, can be used to treat metabolic acidosis. Citrates are metabolized to bicarbonate, which helps raise systemic pH.
Q10: Are there long-term effects of citric acid/citrate use?
A: Prolonged or excessive use can potentially lead to tooth enamel erosion due to the acidity of the solution. Regular dental check-ups are advisable.
