Alfacalcidol

Fact Checked

Medically reviewed by Kenny Cheuk Yin Cheung, Pharmacist

Last updated on 16/07/2021.

GENERIC NAME: Alfacalcidol

CHINESE NAME: 阿法骨化醇

BRAND NAME(S) IN HONG KONG: One-Alpha, Alpha D3, Bon-One

DRUG CLASS: Vitamins

SUB CLASS: Vitamin D analogue

USED FOR: Hyperparathyroidism, Nutritional rickets, Osteomalacia, Renal osteodystrophy, Neonatal hypocalcemia

AVAILABLE DOSAGE FORMS:
– 0.25 mcg, 0.5 mcg, 1 mcg (capsules)
– 2 mcg/ml (oral drops)

What is Alfacalcidol for?

Alfacalcidol is an analogue of Vitamin D, which plays an essential function in calcium absorption and bone growth. Alfacalcidol helps you absorb more calcium and phosphorus which are minerals needed by the body to build strong bones and teeth. It is used to treat various diseases associated with calcium levels in your body, such as hyperparathyroidism or hypoparathyroidism (abnormal levels of parathyroid hormone), renal osteodystrophy (bone disease caused by kidney problems), certain types of rickets and osteomalacia (softening of bones) and neonatal hypocalcemia (low calcium levels in the blood in newborn babies).

How to use it?

Alfacalcidol is available as capsules or oral drops, which are taken by mouth. It should be taken with food. If you are taking the capsule, swallow it whole with a glass of water. If you are taking the oral drops, shake the bottle well before you take it to ensure that the liquid is evenly mixed. Use the dropper provided to measure the prescribed dose.

Hyperthyroidism, hypothyroidism, renal osteodystrophy, rickets, or osteomalacia
Adult
Initially 1 mcg daily, adjust subsequent doses according to individual responses and conditions. Doses are increased in increments of 0.25-0.5 mcg daily. Usual maintenance dose is 0.25-1 mcg daily. Dose may be discontinued if hypercalcaemia occurs.
Elderly
Initially 0.5 mcg daily, adjust subsequent doses according to individual responses and conditions. Doses are increased in increments of 0.25-0.5 mcg daily. Usual maintenance dose is 0.25-1 mcg daily. Dose may be discontinued if hypercalcaemia occurs.
Child over 1 month
20 kg and above: Initially 1 mcg daily, adjust subsequent doses according to individual responses and conditions. Doses are increased in increments of 0.25-0.5 mcg daily. Usual maintenance dose is 0.25-1 mcg daily. Dose may be discontinued if hypercalcaemia occurs.
Less than 20 kg: Initially 0.05 mcg per kg body weight daily.
Neonates and infants
Initially 0.05-0.1 mcg per kg body weight daily.

Neonatal hypocalcemia
Neonates and infants
Initially 0.05-0.1 mcg per kg body weight daily. May require up to 2 mcg/kg in severe cases.

What are the side effects of Alfacalcidol?

Common side effects of Alfacalcidol include headache, nausea, vomiting, diarrhoea, loss of appetite, constipation, stomach pain or discomfort, and skin rash or itching.

Who should not take Alfacalcidol?

– People allergic to any component of the formulation
– Anyone who has an increased calcium or phosphate level in blood
– Anyone who has metastatic calcification
– Patients with Vitamin D toxicity

Pharmacist Tips:

– Alfacalcidol must be taken regularly for it to be effective. Continue taking Alfacalcidol even when you feel well.
– Your doctor may require you to have routine blood tests when taking this medicine.
– Store the oral drops in the refrigerator (between 2-8°C). Do not allow it to freeze as the medicine will become ineffective and has to be thrown away.

Common dosing schedule:
Alfacalcidol is taken at meal time. Try to take it at the same time each day.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Alfacalcidol may interact with:
– Medicines or supplements containing Vitamin D or Calcium
– Magnesium-containing antacids
– Anticonvulsants, e.g. Phenobarbital, Phenytoin, Sodium Valproate
– Thiazide diuretics, e.g. Hydrochlorothiazide
– Aluminium hydroxide
– Sucralfate
– Digoxin

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Alfacalcidol in Hong Kong?

In Hong Kong, Alfacalcidol is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Alfacalcidol in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.