1. Clinical Overview
Disodium Hydrogen Citrate is an oral systemic alkalizer and urinary alkalinizing agent. It is a sodium salt of citric acid that, upon metabolism, increases the plasma bicarbonate concentration, buffers excess hydrogen ion concentration, and raises blood and urinary pH. It is primarily used to treat metabolic acidosis and to alkalinize urine in conditions like uric acid and cystine stone prophylaxis. In the Indian context, it is widely used as an adjunctive therapy for gout and as a urinary alkalinizer in UTIs.
| Onset | Duration | Bioavailability |
|---|---|---|
| Urinary alkalinization begins within 30 minutes of oral administration. | The duration of effect on urinary pH is approximately 3 to 4 hours per dose. | Not specifically quantified for the salt itself; citrate ions are well absorbed from the gastrointestinal tract. |
2. Mechanism of Action
Disodium Hydrogen Citrate dissociates in the gastrointestinal tract to provide citrate ions. These ions are absorbed and oxidized in the liver via the Krebs cycle, yielding bicarbonate (HCO3-). This bicarbonate enters the systemic circulation, increasing the alkali reserve (buffering capacity) of the blood and extracellular fluid. It neutralizes excess hydrogen ions (H+), correcting metabolic acidosis. In the kidneys, the increased bicarbonate load leads to enhanced excretion of bicarbonate in the urine, raising urinary pH.
3. Indications & Uses
- Treatment of chronic metabolic acidosis
- Urinary alkalinization for management of uric acid and cystine renal stones
- Adjuvant therapy in the management of gout
4. Dosage & Administration
Adult Dosage: 10-20 ml (2.8gm - 5.6gm of Disodium Hydrogen Citrate) diluted in a glass of water, 3-4 times daily. Dose must be individualized based on urinary pH (target 6.5-7.5) or plasma bicarbonate levels.
Administration: Must be diluted in a full glass (at least 120-180 ml) of water before ingestion. Take after meals to minimize GI upset. Do not take with milk or other high-calcium products concurrently to avoid potential formation of calcium citrate complexes. Monitor urinary pH with pH paper to titrate dose.
5. Side Effects
Common side effects may include:
- Nausea
- Abdominal discomfort or cramps
- Diarrhea (due to osmotic effect)
- Alkaline taste
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Potassium-Sparing Diuretics (Amiloride, Spironolactone) | Increased risk of hyperkalemia due to reduced renal potassium excretion in an alkaline environment. | Major |
| Lithium | Increased urinary pH can decrease renal lithium clearance, leading to increased lithium levels and potential toxicity. | Major |
| Salicylates (Aspirin) | Alkalinization of urine significantly increases renal excretion of salicylates. This is used therapeutically in poisoning but can reduce efficacy of low-dose aspirin for cardioprotection. | Moderate |
| Methenamine (Hexamine) | Alkaline urine inactivates methenamine, which requires an acidic urine to release formaldehyde as an antibacterial. | Major |
| Quinolone Antibiotics (Ciprofloxacin) | Antacids and alkalinizing agents can reduce absorption of quinolones. Administer Disodium Hydrogen Citrate at least 2 hours before or 4 hours after quinolones. | Moderate |
| Tetracycline Antibiotics | May impair absorption of tetracyclines. Separate administration by 2-3 hours. | Moderate |
| Anticholinergics | May increase absorption and systemic effects of Disodium Hydrogen Citrate by delaying gastric emptying. | Minor |
7. Patient Counselling
- DO dilute the syrup in a full glass of water before drinking.
- DO take after meals if it causes stomach upset.
- DO monitor your urinary pH with pH paper as advised by your doctor to adjust the dose.
- DO inform all your doctors and your pharmacist that you are taking this medicine.
- DO maintain adequate fluid intake (2-3 liters per day unless contraindicated).
- DON'T take it undiluted.
- DON'T take it simultaneously with milk or calcium supplements/antacids. Separate by at least 2 hours.
- DON'T use it as a routine antacid for heartburn without medical advice.
- DON'T exceed the prescribed dose.
8. Toxicology & Storage
Overdose: Symptoms of severe metabolic alkalosis: Irritability, neuromuscular excitability (tingling, tetany, muscle cramps), confusion, slow/shallow breathing (compensatory hypoventilation), hypokalemia, and potentially seizures or coma. Symptoms of sodium overload: Hypertension, worsening edema, pulmonary congestion.
Storage: Store at room temperature (15-30°C), protected from light and moisture. Keep the bottle tightly closed. Keep out of reach of children. Do not freeze. Discard any unused medicine after the expiry date.