Hypophosphataemia may be asymptomatic, but clinical symptoms usually become apparent when plasma phosphate concentrations fall below 0.3mmol/L. Possible symptoms include: weakness, anorexia, malaise, tremor, paraesthesia, seizures, acute respiratory failure, arrhythmias, altered mental status and hypotension.
Suggested starting doses:
Mild Hypophosphataemia (0.6-0.69mmol/L)
No treatment required.
Moderate Hypophosphataemia (0.3-0.59mmol/L):
Phosphate Sandoz® 1-2 tablets orally three times daily (each tablet contains 16mmol phosphate, 3mmol potassium and 20mmol sodium). Oral replacement is usually sufficient but consider intravenous replacement if patient has phosphate level 0.3-0.5mmol/L and is symptomatic or nil-by-mouth or unlikely to absorb oral phosphate.
Sodium glycerophosphate 21.6% IV 20mmol (20ml) in 500ml glucose 5% over 12 hours. The 20ml solution contains 20mmol phosphate (1mmol/ml) and 40mmol sodium (2mmol/ml).
Severe Hypophosphataemia (<0.3mmol/L):
Phosphate level <0.3mmol/L and patient has impaired renal function:
Sodium glycerophosphate 21.6% IV 20mmol (20ml) in 500ml glucose 5% over 12 hours.
Phosphate level <0.3mmol/L and patient has normal renal function:
Sodium glycerophosphate 21.6% IV 40mmol given as 2 x 12 hour infusions, i.e. 20mmol (20ml) in 500ml glucose 5% over 12 hours x 2.
Content last reviewed July 2020