Is Shohl's Solution an Example of Alkali Therapy?
Yes, Shohl's solution (sodium citrate) is definitively an example of alkali therapy used to correct metabolic acidosis, though it carries significant risks in certain patient populations that must be carefully considered. 1
What is Shohl's Solution?
Shohl's solution is a sodium citrate preparation (also marketed as Bicitra™) that functions as an alkalinizing agent. 1 Citrate salts work by being metabolized to bicarbonate in the body, thereby raising blood pH and correcting metabolic acidosis. 2, 3
Clinical Applications of Alkali Therapy
Potassium citrate (not Shohl's solution) is the preferred form of citrate alkali therapy for:
- Maintaining alkaline urine in patients with uric acid and cystine kidney stones 2
- Correcting acidosis in renal tubular disorders 2
- Preventing recurrent calcium oxalate stones with target urinary pH of 6.0-6.5 4, 5
- Chronic metabolic acidosis when serum bicarbonate falls below 22 mmol/L 1, 6
Sodium citrate (Shohl's solution) has more limited applications due to its sodium load, which increases urinary calcium excretion and may worsen stone formation. 7
Critical Safety Warning: Aluminum Toxicity Risk
The most important clinical caveat is that citrate-containing alkali salts (including Shohl's solution) should be absolutely avoided in CKD patients exposed to aluminum-containing medications. 1
This combination can cause acute aluminum neurotoxicity, a potentially fatal syndrome characterized by: 1
- Agitation and confusion
- Myoclonic jerks and seizures
- Coma and death in severe cases
The mechanism: citrate salts markedly enhance intestinal aluminum absorption, leading to rapid accumulation in patients with impaired renal clearance (GFR < 30 mL/min/1.73 m²). 1 This syndrome has occurred when aluminum-containing phosphate binders were given simultaneously with sodium citrate for acidosis correction. 1
Potassium Citrate vs. Sodium Citrate: A Critical Distinction
Potassium citrate is superior to sodium citrate for long-term alkali therapy because: 7
- Sodium citrate increases urinary calcium excretion due to sodium load, potentially promoting calcium stone formation 7
- Potassium citrate decreases urinary calcium while increasing citrate, reducing calcium oxalate saturation 7
- Sodium citrate significantly increases brushite (calcium phosphate) and sodium urate saturation 7
- Potassium citrate does not alter brushite saturation 7
Monitoring Requirements
When using any citrate-based alkali therapy:
- Monitor serum potassium within 1-2 months to detect hyperkalemia 5, 2
- Check serum bicarbonate at least every 3 months in patients with GFR <30 mL/min/1.73 m² 6
- Measure urinary pH within 6 months to verify therapeutic response 4, 5
- Watch for signs of potassium intoxication: listlessness, weakness, mental confusion, tingling of extremities 2
Contraindications and Cautions
Avoid citrate alkali therapy in: 6
- Lactic acidosis (use bicarbonate instead)
- Hepatic insufficiency (impaired citrate metabolism)
- Concurrent aluminum exposure 1
Use with extreme caution in: