Vitamin D3 (Cholecalciferol) Injection

Vitamin D3 (Cholecalciferol) Injection

Available presentation(s): 1, 2 mL. Verify the exact concentration and total active quantity on the prescription and dispensing label.

Introduction: Colecalciferol (vitamin D3) is converted to active metabolites that regulate calcium and phosphate homeostasis. Injectable high-dose vitamin D is reserved for selected patients where oral therapy is unsuitable and requires careful monitoring.

Dosage: Dose and interval must be based on indication, baseline 25-hydroxyvitamin D, calcium, renal function, malabsorption and concurrent vitamin D intake. The 50,000 IU/mL presentation is high-alert; prescribe in international units and verify volume. Avoid repeated empirical dosing without laboratory review.

Mechanisms of Action: Converted in the liver to 25-hydroxyvitamin D and in the kidney/other tissues to calcitriol, which increases intestinal calcium/phosphate absorption and affects bone, muscle and immune pathways.

Contraindications & Precautions: Contraindicated in hypercalcaemia, hypervitaminosis D and hypersensitivity. Use caution in renal disease, nephrolithiasis, granulomatous disease, lymphoma and primary hyperparathyroidism. Monitor calcium, phosphate, renal function and 25-OH-D.

Interactions: Thiazides increase hypercalcaemia risk; digoxin toxicity/arrhythmias may be worsened by hypercalcaemia. Other vitamin D, calcium and phosphate products increase cumulative exposure. Some anticonvulsants and glucocorticoids reduce vitamin D effect.

Adverse Reactions / Side Effects: Injection-site reactions may occur. Excess causes hypercalcaemia with nausea, constipation, weakness, polyuria, dehydration, confusion, nephrolithiasis, renal impairment and arrhythmias.

Pregnancy & Breastfeeding: Correct deficiency in pregnancy using guideline-based doses. Avoid high-dose injectable treatment unless clearly indicated and monitored. Vitamin D enters breast milk; account for maternal and infant supplementation.

Storage: Store under the conditions stated on the Optimus dispensing label and product-specific worksheet. Protect from light where labelled. Do not freeze unless explicitly validated. Maintain cold chain if the label requires refrigeration. Do not use after the assigned beyond-use date or if there is visible particulate matter, precipitation, colour change, loss of container integrity or evidence of improper storage. Once entered, follow the validated in-use time; do not assume a compounded vial is multi-dose.

References

• New Zealand Formulary (NZF), current online edition; product-specific approved data sheets where available; USP Pharmaceutical Compounding—Sterile Preparations; and Optimus Healthcare validated formulation, sterility/endotoxin controls and assigned beyond-use date.
• New Zealand Formulary. Colecalciferol monograph, current edition; NIH ODS Vitamin D Health Professional Fact Sheet.
• NIH Office of Dietary Supplements. Health Professional Fact Sheets (vitamins and minerals), current online editions. https://ods.od.nih.gov/factsheets/list-VitaminsMinerals/