One-Alpha (Alfacalcidol)

Prescription medicineOnly Available By Prescription

Top brand choice

Strength Pack Size Qty
Strength
1mcg
Pack Size
Qty
What if I find a lower price with another pharmacy?

We guarantee the lowest price on all of our prescription products. If you find your medications cheaper at any other recognized licensed mail order pharmacy, we will not only match their price, we will beat it by 25% of the difference. It is our 125% price match guarantee!

Example: If you find a product on Canada Drugs Direct for $50.00 and find the same product for $40.00 at another mail order pharmacy, we will provide you with a $12.50 discount, bringing your total to $37.50.

To get the discount please make sure to mention the price match to the customer service team when they call to collect payment for your order. Or call toll free at 1-888-904-8467 to place the order through the phone.

Terms & Conditions of Program

  • Guaranteed lowest price is only valid at the time of sale.
  • We will only match the current advertised price.
  • Products must be identical and in stock at the time of placing an order with a licensed mail order pharmacy. They must be an online Canadian pharmacy with an address in Canada.
  • Products must be authentic in brand and size (same manufacturer, same country of manufacture, same pack size, same strength and same quantity).
  • Products must be new. We cannot match the price of any used, short expiry or expired product.
  • Price match can only be issued over the phone with our customer service team. Please note at this time we cannot offer price matching for the products Ozempic or Saxenda.
What is a Generic Drug?

A generic drug is a copy of the brand-name drug with the same dosage, safety, strength, quality, consumption method, performance, and intended use. Before generics become available on the market, the generic company must prove it has the same active ingredients as the brand-name drug and works in the same way and in the same amount of time in the body.

The only differences between generics and their brand-name counterparts is that generics are less expensive and may look slightly different (eg. different shape or color), as trademarks laws prevent a generic from looking exactly like the brand-name drug.

Generics are less expensive because generic manufacturers don't have to invest large sums of money to develop a drug. When the brand-name patent expires, generic companies can manufacture a copy of the brand-name and sell it at a substantial discount.

Description

One-Alpha is an oral or injectable formulation of alfacalcidol, a vitamin D analog used in the management of conditions related to impaired calcium metabolism. It is indicated for the treatment of renal osteodystrophy, hypocalcemia, rickets, osteomalacia, and secondary hyperparathyroidism, particularly in patients with chronic kidney disease (CKD). Alfacalcidol is converted in the liver to calcitriol (1,25-dihydroxyvitamin D3), the active form of vitamin D, thereby bypassing the need for renal 1-alpha hydroxylation. This makes One-Alpha especially useful in patients with renal insufficiency.

Fact Table

Formula

C27H44O2

License

EMA; Japan PMDA; not FDA-approved

Bioavailability

~100% (oral)

Legal status

Prescription only (Rx)

Chemical Name

(5Z,7E)-(1R,3R,5Z,7E,22E)-(1,25-dihydroxy-9,10-secocholesta-5,7,10(19),22-tetraen-3-ol)

Elimination half-life

~3–6 hours (parent), ~18 hours (metabolite)

Dosage (Strength)

0.25 mcg, 0.5 mcg, 1 mcg capsules; oral drops; IV injection (0.01–2 mcg/mL)

Pregnancy

Category C – caution advised

Brands

One-Alpha, Alfacalcidol (generic)

Protein binding

~85%

PubChem CID

5280734

MedlinePlus

Not listed (US not approved)

ChEBI

CHEBI:31705

ATC code

A11CC03

DrugBank

DB01436

KEGG

D00938

Routes of administration

Oral, Intravenous

Directions

Dosage should be individualized based on serum calcium, phosphate, and parathyroid hormone (PTH) levels.

  • Adults (oral): Typically 0.25–1 mcg/day, with adjustments at intervals of 2–4 weeks
  • Pediatric dosing: Weight-based and condition-specific
  • IV formulation (e.g., for dialysis patients): Administered as prescribed during dialysis sessions

Monitoring of serum calcium, phosphate, and PTH is essential during therapy. Reduce or interrupt treatment if hypercalcemia or hyperphosphatemia occurs.

Ingredients

Each capsule or mL of solution contains:

  • Alfacalcidol 0.25 mcg, 0.5 mcg, or 1 mcg

Inactive ingredients may vary by dosage form and may include:

  • Capsule: arachis oil (peanut oil), gelatin, glycerol
  • Oral drops and IV forms: propylene glycol, ethanol, or other stabilizers

Contraindications

One-Alpha is contraindicated in patients with:

  • Hypercalcemia
  • Hyperphosphatemia (especially in patients not on dialysis)
  • Hypersensitivity to alfacalcidol or formulation components
  • Vitamin D toxicity

Cautions

Use with caution in patients predisposed to hypercalcemia, such as those with sarcoidosis or certain malignancies. Frequent monitoring is critical, particularly during initiation or dose adjustment. Concomitant use with calcium supplements, thiazide diuretics, or high-phosphate diets increases the risk of calcium-phosphate imbalance. Avoid use in patients with nephrolithiasis or significant cardiovascular calcification. Ensure adequate hydration to reduce the risk of hypercalcemia-related renal complications.

Side Effects

Common and potential side effects include:

  • Hypercalcemia
  • Hyperphosphatemia
  • Anorexia or nausea
  • Weakness or fatigue
  • Headache
  • Pruritus
  • Rare: nephrocalcinosis, vascular calcification, or metastatic calcification

IMPORTANT NOTE: The information provided above is for general awareness and educational purposes only. It is not intended to diagnose, treat, or replace professional medical or veterinary advice. Always consult your physician, pharmacist, or veterinarian regarding the safety, suitability, and proper use of any medication for yourself or your pet.

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