Moderate hypocalcaemia
Moderate hypocalcaemia usually presents with muscle cramps, spasms or paraesthesia. It is typically caused by hypoparathyroidism.
In an adult, hypocalcaemia can be corrected with an oral calcium supplement. Patients with hypoparathyroidism usually also require oral calcitriol. Patients with vitamin D deficiency should be treated with oral colecalciferol (see Vitamin D treatment regimens for doses). In children, calcium and calcitriol are usually used together.
For an adult with moderate hypocalcaemia, a reasonable initial regimen is:
1 calcium carbonate 1.25 to 1.5 g (elemental calcium 500 to 600 mg) orally, twice daily, with food hypocalcaemia, moderate (adult) calcium carbonate
OR
1 calcium citrate 2.38 g (elemental calcium 500 mg) orally, twice daily hypocalcaemia, moderate (adult) calcium citrate
PLUS with either of the above regimens in patients with hypoparathyroidism
calcitriol 0.25 to 0.5 micrograms orally, twice daily. hypocalcaemia, moderate (adult) calcitriol
For a child with moderate hypocalcaemia, a reasonable initial regimen is:
calcium carbonate 100 mg/kg (elemental calcium 40 mg/kg) orally, daily in 4 to 6 divided doses; increase as required (doses up to 300 to 500 mg/kg [elemental calcium 120 to 200 mg/kg] may be required) hypocalcaemia, moderate (child) calcium carbonate
PLUS
calcitriol 0.015 micrograms/kg orally, daily. hypocalcaemia, moderate (child) calcitriol
Review the patient's symptoms, and measure serum calcium and phosphate concentrations every 1 to 2 weeks. Adjust the dose or frequency of treatment as needed, until therapy is stabilised. Calcitriol raises the serum calcium concentration over 1 to 2 days and the dose requirement varies significantly among patients. Once stable, measure 24-hour urine calcium excretion to check for hypercalciuria. If hypercalciuria is present, reduce the dose of calcitriol slightly.
Long-term therapy may be necessary if the cause of hypocalcaemia is permanent (eg damaged parathyroid gland); see Long-term management of hypocalcaemia.