Medication Summary
Calcium and calcitriol (active vitamin D) are the mainstays of treatment for hypoparathyroidism and pseudohypoparathyroidism (PHP). To relieve immediate severe symptoms of hypocalcemia, an intravenous bolus of 9-15 mg elemental calcium/kg (1 g calcium gluconate = 90 mg elemental calcium = 4.5 mEq elemental calcium) is administered over 10-30 min. Then, either intermittent boluses or a continuous IV infusion is initiated (60 mg elemental calcium/kg/d). Oral calcium is initiated for a total of 100 mg elemental calcium/kg/d divided 4 times daily. Once serum calcium concentrations range from 8-9 mg/dL, the calcium dose is weaned to the minimum dose necessary to maintain a low-normal serum calcium concentration.
In some studies, synthetic human PTH 1-34, both once and twice daily, has been shown to effectively treat children with hypoparathyroidism. However, this therapy is not yet approved for the treatment of hypoparathyroidism. [6]
A study that included data from 42 children with hypoparathyroidism who presented with epileptic seizures reported that antiepileptic drug treatment does not improve seizure outcomes in children with parathyroid disorders. [7]
Calcium supplements
Class Summary
Numerous calcium preparations are available. An intravenous dose quickly but transiently corrects the serum calcium concentration and relieves hypocalcemic symptoms. Severe hypocalcemia can be treated with a continuous calcium infusion; a transition to the oral form can be made when the serum calcium concentration is within a safe range. Tailoring of calcium dosing to each patient's needs is essential. In fact, once adequate amounts of active vitamin D are present, some patients can absorb all the calcium they need through the diet and oral calcium preparations can be discontinued. Intravenous calcium gluconate is preferred in children. For enteral preparation in young children, liquid calcium glubionate (Neo-Calglucon, Calcionate) or calcium gluconate is preferred. For older children and adolescents, the authors prefer calcium citrate over calcium carbonate because the latter is not well absorbed through the gut and it needs to be taken with a meal because it requires acid for absorption.
Calcium citrate (Cal-Citrate, Citracal)
Oral formulation usually used as supplementation to IV calcium therapy. Moderates nerve and muscle-performance by regulating action potential excitation threshold and facilitates normal cardiac function. Give amount needed to supplement diet to reach recommended daily amounts.
Calcium gluconate
Used to correct serum calcium concentration and relieve hypocalcemic symptoms. Moderates nerve and muscle performance and facilitates normal cardiac function (1 g = 90 mg elemental = 4.5 mEq elemental calcium).
Calcium glubionate (Neo-Calglucon)
PO calcium can be used to correct mild hypocalcemia and for maintenance therapy. Moderates nerve and muscle performance and facilitates normal cardiac function (1 g = 64 mg elemental = 3.3 mEq elemental calcium).
Calcium carbonate (Tums, Oscal)
An alternative PO form of calcium that can be used to correct mild hypocalcemia and for maintenance therapy (1 g = 400 mg elemental = 20 mEq elemental calcium).
Vitamin D supplements
Class Summary
1,25-Dihyroxyvitamin D, calcitriol, is critical for maintaining serum calcium concentrations. Parathyroid hormone (PTH) deficiency impairs conversion of inactive vitamin D to the active form by renal 1-alpha-hydroxylase. To bypass this PTH-dependent step, the active form of vitamin D is administered and may eliminate the need for PO calcium once the patient has stabilized.
Calcitriol (Rocaltrol, Calcijex)
This drug has a short half-life, and its effects are quickly reversed with withdrawal of the medication in case of hypercalcemia. Calcitriol is available in 0.25- and 0.50-mcg gel cap or an oral solution of 1 mcg/mL. Also available in an injectable form of 1 mcg/mL and 2 mcg/mL.
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Electrocardiogram (ECG) findings in severe hypocalcemia.
