Vetdrugs 2.0Sodium acid phosphate is an inorganic phosphate salt used for phosphorus replacement. Its principal veterinary role is correction of clinically important hypophosphatemia, including selected periparturient disorders in cattle. The amount of available phosphorus depends on the salt and formulation. Its replacement function follows from delivery of metabolically available inorganic phosphate.
Group
Inorganic phosphate replacement
Mechanism of Action
Absorbed or administered phosphate enters extracellular and intracellular phosphate pools. It supports ATP generation, phosphorylated metabolic intermediates, membrane phospholipids and acid–base buffering. In deficient erythrocytes, restoration of phosphate availability supports energy-dependent membrane function. Repletion therefore addresses metabolic and red-cell dysfunction attributable to an inadequate phosphate supply.
Dose Rates
Cattle
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Postparturient haemoglobinuria | 20150 mg/animal | IV | Every 12 h | 40.3% w/v sodium acid phosphate: 50 mL per dose, for three doses total. This is salt mass, not elemental phosphorus; use only the matching concentration. |
| Hypophosphataemia - oral replacement | 200 g/animal | PO | Adult cattle with functioning rumen: feed-grade monosodium phosphate 200 g orally. Hydrate and elemental-phosphorus content must be checked before selecting a preparation. Do not substitute a differently hydrated SAP preparation without checking the actual phosphate equivalent. | |
| Severe hypophosphataemia - monohydrate protocol | 30 g/animal | IV | Specific alternative: 300 mL of 10% sodium dihydrogen phosphate MONOHYDRATE, given slowly IV. This is not the corresponding volume of a 40.3% SAP preparation. Do not substitute a differently hydrated SAP preparation without checking the actual phosphate equivalent. |
Indications
- Correction of clinically significant hypophosphatemia in cattle or other supported veterinary patients.
- Phosphate replacement in selected postparturient bovine hemoglobinuria associated with phosphorus deficiency.
- Treatment of documented phosphate depletion contributing to selected periparturient weakness or metabolic dysfunction.
Contraindications
- Hyperphosphataemia, hypocalcaemia, hypernatraemia or oliguric renal failure.
Interactions
- Calcium and magnesium can form insoluble phosphate precipitates; do not mix in the same solution.
- Oral calcium/aluminium binders can reduce phosphate absorption.
Adverse effects
- Hypocalcaemia, hypotension, hypernatraemia, renal injury or soft-tissue mineralisation with excess.
Toxicity
Stop phosphate delivery for overcorrection; monitor ionised calcium, phosphorus, renal function and circulation.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Tenophos Vet 40.3% injection Morvel Laboratories Manufacturer states equivalent elemental phosphorus 80 mg/mL; do not list it as an additional active or add it again to the dose. | Injection | 403 mg / mL | IM, IV, SC |
Monitoring and Administration
Monitor inorganic phosphorus, calcium and renal function during treatment. Correct severe anaemia independently when present.
Do not give an IV phosphate preparation within 2 hours of IV calcium in cattle; avoid admixture with calcium-containing fluids.
The 40.3% product recommendation below is a veterinary sodium acid phosphate regimen. Do not substitute a mixed mono/dibasic human phosphate vial by matching mL.