Vistella (Calcifediol) in Australia: Monthly Vitamin D for Deficiency

Vistella is now TGA-approved as Australia's first high-strength calcifediol preparation. This once-monthly vitamin D treatment offers pharmacists a new option for patients who don't respond adequately to standard cholecalciferol supplementation.

What is Calcifediol? Understanding 25-Hydroxyvitamin D

Calcifediol is 25-hydroxyvitamin D (25(OH)D) – the metabolite your liver produces when it processes cholecalciferol (vitamin D3). When pathology labs measure a patient's "vitamin D level," they're measuring serum 25(OH)D concentrations.

This distinction matters clinically. Calcifediol bypasses hepatic 25-hydroxylation entirely, resulting in:

• More predictable intestinal absorption
• Faster elevation of serum 25(OH)D levels
• Consistent dose-response regardless of baseline vitamin D status

TGA Approval and Scheduling Details

Vistella received TGA approval on 9 July 2025 and was registered in the Australian Register of Therapeutic Goods (ARTG) on 6 March 2025.

Detail	Information
Active ingredient	Calcifediol 255 micrograms
Sponsor	Aspen Pharmacare Australia Pty Ltd
Scheduling	S4 – Prescription Only Medicine
Black Triangle	Yes – enhanced reporting for 5 years
ARTG number	413380

The Black Triangle designation means pharmacists should actively report any suspected adverse events through the TGA's adverse event reporting system.

Vistella Dosing: How to Prescribe Calcifediol

Standard Dosing for Vitamin D Deficiency

255 micrograms (one capsule) once monthly, taken orally with or without food.

Severe Vitamin D Deficiency

For patients with baseline 25(OH)D less than 12 ng/mL (30 nmol/L):

• One capsule per fortnight until serum levels normalise
• Then transition to monthly maintenance dosing

Dosing Advantages

Monthly administration produces stable serum 25(OH)D concentrations without the peaks and troughs seen with weekly high-dose cholecalciferol. This improves adherence and may reduce hypercalcaemia risk.

Calcifediol vs Cholecalciferol: When to Choose Vistella

Standard over-the-counter cholecalciferol works well for most patients with vitamin D deficiency. Calcifediol is specifically indicated when cholecalciferol proves inadequate or inappropriate.

1. Malabsorption Syndromes

Calcifediol is more hydrophilic (water-soluble) than cholecalciferol, improving absorption in patients with fat malabsorption:

• Inflammatory bowel disease (Crohn's, ulcerative colitis)
• Coeliac disease
• Post-bariatric surgery
• Pancreatic insufficiency
• Short bowel syndrome

2. Hepatic Impairment and Liver Disease

Cholecalciferol requires hepatic CYP450 enzymes (CYP2R1, CYP27A1) for 25-hydroxylation. Patients with liver disease often have impaired conversion. Calcifediol bypasses this step entirely.

3. Obesity and Vitamin D Deficiency

Vitamin D is sequestered in adipose tissue. Obese patients frequently show suboptimal responses to cholecalciferol supplementation. Clinical studies demonstrate calcifediol achieves target 25(OH)D levels more reliably in this population.

4. CYP450 Drug Interactions

Medications affecting hepatic enzyme activity can alter cholecalciferol metabolism unpredictably:

• CYP3A4 inducers (rifampicin, phenytoin, carbamazepine)
• CYP3A4 inhibitors (ketoconazole, ritonavir)

Calcifediol avoids this interaction pathway.

5. Rapid Correction Required

Calcifediol raises serum 25(OH)D within 1-2 weeks versus 6-8 weeks for cholecalciferol. This faster onset suits clinical scenarios requiring urgent correction.

Calcifediol Potency: Dosing Equivalence

Calcifediol is approximately 3.2 times more potent than cholecalciferol at standard doses. At higher doses (above 2000 IU cholecalciferol equivalent), the difference increases to 5.5-12 times greater potency.

This increased potency explains the S4 scheduling – hypercalcaemia risk is higher than with over-the-counter vitamin D supplements.

Pharmacist Counselling Points for Vistella

When dispensing calcifediol, cover these essential points:

Administration

• Take one capsule on the same day each month
• Can be taken with or without food
• Swallow whole – do not crush or chew

Why This Form of Vitamin D?

• Explain that calcifediol is "pre-activated" vitamin D
• Their body can use it directly without liver processing
• May work better than standard vitamin D for their specific condition

Monitoring Requirements

• Doctor will check vitamin D levels periodically
• Initial check typically 3 months after starting treatment
• Dose adjustments based on serum 25(OH)D results

Warning Signs of Vitamin D Toxicity

• Nausea, vomiting, poor appetite
• Constipation
• Weakness, fatigue
• Excessive thirst and urination
• Confusion
• Seek medical attention if these occur

Calcium Intake

• Adequate dietary calcium (1000-1300mg daily) needed for vitamin D effectiveness
• Discuss calcium-rich foods or supplements if dietary intake insufficient

Contraindications and Precautions

Contraindications

• Hypercalcaemia
• Hypervitaminosis D
• Known hypersensitivity to calcifediol or excipients

Use With Caution

• Renal impairment: Reduced clearance of 25(OH)D metabolites
• Granulomatous diseases: Sarcoidosis, tuberculosis – increased vitamin D sensitivity
• Concurrent thiazide diuretics: Increased hypercalcaemia risk
• Cardiac glycosides: Hypercalcaemia potentiates digoxin toxicity

Place in Therapy: Where Vistella Fits

Clinical Scenario	First-Line	Consider Calcifediol
Routine vitamin D deficiency	Cholecalciferol OTC	No
Malabsorption syndrome	Cholecalciferol trial	If inadequate response
Liver disease	-	Yes – first-line
Obesity with poor response	Cholecalciferol trial	If target not achieved
CYP450 drug interactions	-	Yes – consider early
Rapid correction needed	-	Yes – faster onset

For most patients with straightforward vitamin D deficiency, over-the-counter cholecalciferol remains appropriate, effective, and cost-efficient.

Vistella fills a specific therapeutic gap: patients who either don't respond to cholecalciferol or have conditions impairing its metabolism.

Key Takeaways for Pharmacists

1. Vistella = calcifediol 255mcg – the 25-hydroxylated (pre-activated) form of vitamin D
2. Monthly dosing simplifies adherence versus daily/weekly regimens
3. Best candidates: malabsorption, liver disease, obesity, CYP450 interactions, need for rapid correction
4. S4 scheduling – prescription required; monitor for hypercalcaemia
5. Black Triangle medicine – enhanced adverse event reporting for 5 years
6. Not a replacement for standard cholecalciferol in routine deficiency

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References: TGA Australian Public Assessment Report (AUSPAR) for Vistella (July 2025), Vistella Product Information, Australian Prescriber – Calcifediol high-strength formulation for vitamin D deficiency