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Alfacalcidol capsules and drops (One-Alpha)

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Alfacalcidol is a type of vitamin D.

You will need to have regular blood tests while you are taking the medicine so that your doctor can adjust your dose.

Make sure you know the symptoms of too much calcium in your blood - these are losing your appetite, feeling thirsty, being sick, feeling tired and losing weight. Please let your doctor know if you develop these symptoms.

Type of medicineA type of vitamin D
Used forTo promote healthy bones
Also calledOne-Alpha®
Alfacalcidol is also called 1α-hydroxycholecalciferol or 1α-hydroxyvitamin D3
Available asCapsules, oral drops and injection

Alfacalcidol is a type of vitamin D. Vitamin D helps to regulate the amount of calcium and phosphate in your body. All three of these substances are important for maintaining healthy, strong bones and teeth.

There are several types of vitamin D available but most other types need 'activating' by the kidneys. Alfacalcidol is a form of vitamin D which does not need this activation process, and so it is particularly helpful for people who need their bones strengthening but who also have kidney problems. You may also need to take mineral supplements along with alfacalcidol.

Alfacalcidol is available as capsules, as oral liquid drops and also as an injection.

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking alfacalcidol it is important that your doctor knows:

  • If you are pregnant or breast-feeding.
  • If you have ever had kidney stones.
  • If you know you have too much calcium in your blood or urine. This can happen with some cancers.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • If you have ever had an allergic reaction to a medicine.
  • Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about alfacalcidol and will provide you with a full list of the side-effects which you may experience from taking it.
  • Take alfacalcidol exactly as your doctor tells you to. It is usually taken as one dose a day. Try to take your doses at the same time of day each day, as this will help you to remember to take it regularly.
  • There are three strengths of capsule and one strength of oral drop available - your doctor will tell you what dose to take each day. Your dose could change from time to time depending upon the results of your routine blood tests.
  • If you forget to take a dose, take it as soon as you remember. If you do not remember until the following day, skip the missed dose. Do not take two doses together to make up for a forgotten dose.

Directions for using One-Alpha® drops

Note: each drop contains 0.1 microgram (100 nanograms) of alfacalcidol.

  1. Remove the bottle cap. (Do not shake the bottle before using.) You will see a dropper which is ready for you to use.
  2. Hold the bottle upside down so that a drop appears at the end of the dropper. If a drop doesn't form, tap the bottle gently with a finger so that it does.
  3. Let the drop fall into your (or your child's) mouth, or catch it on a spoon if this is easier. Your doctor will tell you how many drops to take - count these out carefully to make sure that you (or your child) take the correct number.
  • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress. Your doctor will want you to have regular blood tests during the treatment to check on the amount of calcium in your blood. Your dose of alfacalcidol will be adjusted as a result of having these tests.
  • Treatment with alfacalcidol may be for short periods of time (such as in preparation for surgery), or could be long-term. Please continue to take alfacalcidol regularly unless you are told otherwise by your doctor.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. Alfacalcidol occasionally causes skin rashes but other side-effects could be due to too much calcium being in your blood (see the table below). You will find a full list of side-effects in the manufacturer's information leaflet supplied with your medicine. Please speak with your doctor or pharmacist if any of the following continue or become troublesome.

Alfacalcidol side-effects What can I do if I experience this?
Skin rash and itchinessIf troublesome, speak with your doctor
Loss of appetite, loss of weight, feeling tired, feeling sick, feeling thirsty, sweating, a metallic taste in your mouth, a need to pass urine more oftenThese are signs that there could be too much calcium in your blood. Make an appointment to see your doctor as soon as possible. Your dose may need adjusting or your treatment with alfacalcidol may need to be stopped for a few days

If you experience any other symptoms which you think may be due to alfacalcidol, please speak with your doctor or pharmacist for further advice.

  • Keep all medicines out of the reach and sight of children.
  • Capsules should be stored in a cool, dry place, away from direct heat and light.
  • Oral drops should be kept refrigerated once the bottle has been opened. Do not use or keep an opened bottle for longer than 28 days.

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

If you buy any medicines, check with a pharmacist that they are suitable to take with your other medicines.

If you are having an operation or dental treatment, tell the person carrying out the treatment which medicines you are taking.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Further reading & references

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Prof Cathy Jackson
Document ID:
3404 (v24)
Last Checked:
Next Review:
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