Old and new therapeutic drugs for management of hypophosphat
The treatment of choice for patients with hypophosphatemia varies depending on the cause. Clear causes of hypophosphatemia, such as diuretic or phosphate-binding antacid use, can be easily corrected by drug discontinuation. In patients whose medications cannot be stopped, phosphate supplementation might be necessary. Drip infusion of either sodium phosphate or potassium phosphate might be required for symptomatic patients, especially in severe, acute hypophosphatemia. However, intravenous administration of phosphate can cause hypocalcemia and hyperphosphataemia. When renal function is impaired, serum potassium concentration also needs to be monitored if potassium phosphate is administered.

Oral phosphate is usually the first choice for patients with acute asymptomatic and chronic hypophosphataemia. Various formulations of either sodium phosphate, potassium phosphate, or both, are available. Oral phosphate is rapidly absorbed in the small intestine and excreted into the urine within several hours. Therefore, oral phosphate needs to be administered three or four times per day. Even with this frequent administration, attaining stable serum phosphate concentrations by oral phosphate is impossible. Oral phosphate can also cause several adverse events, including gastrointestinal symptoms such as diarrhea and abdominal pain, and, with chronic treatment, secondary or tertiary hyperparathyroidism, nephrocalcinosis, and renal impairment. The dose of oral phosphate should be modified to avoid the development and exacerbation of these adverse events. Because of these limitations, medication compliance can be a considerable clinical problem.

Cause-specific treatment
- FGF-23-mediated hypophosphataemic diseases: oral phosphate and active vitamin D
-X-linked hypophosphataemia: burosumab
-Fanconi syndrome: oral phosphate, with active vitamin D for some patients
- Hereditary hypophosphataemic rickets with hypercalciuria: oral phosphate
- Vitamin D deficiency: native vitamin D