麥角鈣化醇 (維生素D2)

用途

• Maintenance therapy of parathyroid failure after using parenteral calcium to control hypocalcemic tetany
• Maintenance therapy of parathyroid failure after using parenteral calcium to control hypocalcemic tetany

給藥方式

可能的副作用

• Hypercalcemia
• Hyperphosphatemia
• Nephrocalcinosis
• Soft tissue mineralization

注意事項與禁忌

• Hypercalcemia
• Vitamin D toxicity
• Malabsorption syndrome
• Abnormal sensitivity to the effects of vitamin D
• ### Important Warnings * **Renal Impairment**: Patients with kidney dysfunction may not convert ergocalciferol into the primary active metabolite. Calcitriol or DHT is preferred as they bypass renal activation. * **Hyperphosphatemia**: Use with extreme caution. Elevated calcium and phosphorus simultaneously can lead to severe metastatic soft tissue mineralization (monitor calcium x phosphorus product). * **Monitoring Commitment**: Chronic therapy should not be initiated unless owners are willing to commit to ongoing, rigorous patient monitoring. * **Pregnancy**: Hypervitaminosis D has been implicated in causing teratogenic effects. Weigh potential benefits against risks. * **Nursing**: Large doses of vitamin D are excreted into milk. Consider using milk replacer for offspring of dams receiving therapeutic dosages.

藥物相互作用

• Corticosteroids: Can reduce the effects of vitamin D analogs by decreasing calcium absorption and increasing renal excretion.
• Digoxin: Patients are highly sensitive to the arrhythmogenic effects of hypercalcemia; intensified monitoring is required.
• Verapamil: Patients are sensitive to the effects of hypercalcemia; intensified monitoring is required.
• Mineral Oil: May reduce the amount of orally administered ergocalciferol absorbed from the GI tract.
• Thiazide Diuretics: May cause hypercalcemia when given in conjunction with Vitamin D analogs due to decreased renal calcium excretion.

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