Pharmacy Guide
Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.
Pharmacy Guide
Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.
One-Alpha 0.5 microgram soft capsules
⚠ This medicine appears to have been discontinued
The electronic medicines compendium (emc) no longer publishes a Summary of Product Characteristics for this product, which usually means it is no longer marketed in the UK. The patient leaflet below is kept for reference, but the product may not be available.
If you were prescribed this medicine, other products containing Alfacalcidol may still be available. Do not stop your treatment — ask your pharmacist or GP what to use instead.
What it is and what it is used for
for
One-Alpha contains the active substance alfacalcidol. One-Alpha belongs to a group of medicines called vitamin D analogues. It is a type of vitamin D. Vitamin D controls the levels of two substances in your body. These substances are called calcium and phosphate. Your body needs both of these substances for healthy bones and teeth. One-Alpha works by increasing the amount of vitamin D in your body. This means the levels of calcium and phosphate in your body will increase too. One-Alpha is used to treat diseases where the amount of calcium in your body needs changing. It is used to treat:
- Changes in bone caused by kidney failure (osteodystrophy). •
Changes to your parathyroid glands. These are small glands found in your neck. They make a substance called the parathyroid hormone. This changes the amount of calcium in your body.
- The glands may make the amount of calcium in your blood too high (hyperparathyroidism).
- The glands may make the amount of calcium in your blood too low (hypoparathyroidism).
•
Low levels of calcium in the blood of newborn babies (hypocalcaemia).
•
Softening and deformity of the bones due to lack of calcium (rickets or osteomalacia).
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What you need to know before you take it
e One-Alpha® Do not take One-Alpha
- If you are allergic (hypersensitive) to alfacalcidol or any of the other ingredients. You can find a list of these ingredients in section 6 of this leaflet. •
If you know you have a condition called hypercalcaemia. This means you have high levels of calcium in your blood.
•
If you know that you have a condition called calcification. This means you have high levels of calcium in your body tissues.
If you are unsure if any of the above apply to you, talk to your doctor before taking One-Alpha. Warnings and precautions Talk to your doctor, pharmacist or nurse before taking One-Alpha
- If you are taking any of the medicines in the "Taking other medicines" section below.
- If you have any problems with your kidneys. This includes if you have kidney stones. •
If you have granulomas or sarcoidosis. You may be more sensitive to One-Alpha.
You may get too much calcium or phosphate in your blood when you take this medicine. Please read section 4 of this leaflet so you can spot any signs this may be happening to you. Your doctor may need to change your dose. While you are taking One-Alpha your doctor will take regular blood tests. This is very important in children, patients with kidney problems, or patients on a high dose of medicine. This is to check the level of calcium and phosphate in your blood while you take your medicine. •
Your doctor may prescribe another medicine called a phosphate binding agent to take as well as One-Alpha. This will help to keep the right amount of phosphate in your blood.
•
Your doctor may also prescribe a calcium supplement to take as well as One-Alpha. This is to maintain the right amount of calcium in your blood.
Other medicines and One-Alpha Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines. This includes any medicines which you have bought without a prescription. You must tell your doctor or pharmacist if you are taking any of the following medicines:
- Anticonvulsants (for example, barbiturates, phenytoin, carbamazepine or primidone): for epilepsy or fits. You may need a larger dose of One-Alpha. •
Cardiac glycosides, such as digoxin: for heart problems. You may get too much calcium in your blood. This may cause an abnormal heart beat.
•
Thiazide diuretics, often called "water pills": for increasing the amount of water (urine) that your body makes. You may get too much calcium in your blood.
•
Calcium-containing medicines. You may get too much calcium in your blood.
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•
Other medicines that contain vitamin D. You may get too much calcium in your blood.
•
Antacids containing magnesium: for heartburn or indigestion. You may get too much magnesium in your blood.
•
Medicines containing aluminium. Too much aluminium is toxic.
•
Bile acid sequestrants such as cholestyramine: for lowering your cholesterol level, or to help stop some types of diarrhoea or itching. Your One-Alpha may not enter your blood as usual.
Pregnancy and breast-feeding If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine. Driving and using machines Usually your medicine may have very little effect on your ability to drive or use machines. Check with your doctor if you feel any side effect, for example dizziness, that may stop you from driving or using machines. Important information about some of the ingredients of One-Alpha One-Alpha contains:
- Sesame oil. This may rarely cause severe allergic reactions. Please ask your doctor if you are worried about any of the ingredients in this medicine.
3.
How to take One-Alpha®
Always take this medicine exactly as your doctor or pharmacist has told you. Check with your doctor or pharmacist if you are not sure.
How to take it
the capsule out of the blister Press on the shiny side of the blister. The capsule will come out through the printed side of the foil. Please see the diagram.
How much One-Alpha to take Your doctor will tell you how many capsules to take, or to give your child. At first you will have weekly blood tests to check the levels of some substances in your blood. These tests are to check the levels of calcium, an enzyme called alkaline phosphatase or the parathyroid hormone. This is so your doctor knows that you are taking the dose that is right for you. When you are getting the correct dose you will not need blood tests so often. You may also have other tests such as X-rays. This is also so your doctor knows that the dose is right for you. Your doctor may adjust your dose. Your doctor may ask you to take more or less capsules depending on your test results.
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You may get too much calcium or phosphate in your blood when you take this medicine. Please read section 4 of this leaflet so you can spot any signs this may be happening to you. Your doctor will tell you not to take any more medicine. You will need to have some blood tests. When the blood tests are normal you can start your medicine again. It is important that you only take half the dose you had before. Adults and children weighing more than 20 kilograms: The usual starting dose is 1 microgram each day. This is either 1 brown capsule, 2 red capsules or 4 white capsules. People usually take between 1 and 3 micrograms each day. Most people take between 0.25 and 1 microgram each day once the blood test results show the medicine is working. This is usually one white capsule, or one red capsule or one brown capsule. If you have very low levels of calcium in your blood, your doctor may prescribe between 3 and 5 micrograms each day. Your doctor may prescribe another medicine called a calcium supplement to take as well as One-Alpha. This will help to keep the right amount of calcium level in your blood. Elderly: The usual starting dose is 0.5 microgram each day. This is either 1 red capsule or 2 white capsules. Children: The dose depends on the weight of the child (called bodyweight).
- Newborn and premature babies: The usual starting dose is 0.05 to 0.1 microgram per kilogram of bodyweight each day. If the level of calcium in their blood is very low, up to 2 micrograms per kilogram of bodyweight may be needed each day. A dose of 0.1 microgram per kilogram bodyweight each day is used to stop low blood calcium levels in premature babies. •
Children weighing less than 20 kilograms: The usual starting dose is 0.05 microgram per kilogram bodyweight each day.
If you take more One-Alpha than you should Tell your doctor straight away. You may need to stop taking this medicine. You may get too much calcium or phosphate in your blood. Please read section 4 of this leaflet so you can spot any signs this may be happening to you. If you forget to take One-Alpha If you forget to take your medicine, take it as soon as you remember. Then take the next dose at the usual time. If you have any further questions on the use of this medicine, ask your doctor, pharmacist or nurse.
4. Possible side effects Like all medicines, this medicine can cause side effects, although not everybody gets them. Important side effects to look out for: You must get urgent medical help if you have any of the following symptoms. You may be having an allergic reaction: • You have difficulty breathing Page 4 of 6
• •
Your face or throat swell Your skin develops a severe rash.
You should tell your doctor straight away if you spot any of the following signs which may be due to too much calcium or phosphate in your blood. These side effects may affect up to 1 in 10 people: • You feel weak or have pain in your muscles or bones • You need to pass water (urine) more often • You feel thirsty • You feel fatigue • You feel sick, vomit, have constipation or have lost your appetite • You are sweating a lot • You are having headaches • You feel confused • You feel drowsy. You should tell your doctor as soon as possible if you spot any of the following signs which may be due to problems developing with your kidneys. The frequency of these side effects is not known (cannot be estimated from the available data): Kidney problems:
- Needing to pass water (urine) less often
- Swelling of any parts of your body
- Fever with a pain in your side. Kidney stones may be forming. Kidney stones may cause a sharp spasm in one side of your lower back.
•
Other possible side effects which may affect up to 1 in 10 people are: • Abdominal/stomach pain or discomfort • Rash • Itch. Uncommon possible side effects which may affect up to 1 in 100 people are: • • • • • •
Headache Diarrhoea, vomiting, constipation, nausea Muscle pain Fatigue Calcinosis (deposits of calcium in the body) Feeling weak or unwell.
Rare possible side effects which may affect up to 1 in 1,000 people are:
- Dizziness.
Possible side effects
with unknown frequency (cannot be estimated from the available data):
- Confusion
- Hives (urticaria). Reporting of side effects If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard. By reporting side effects you can help provide more information on the safety of this medicine. Page 5 of 6
How to store it
One-Alpha®
- Keep out of the sight and reach of children.
- Do not take this medicine after the expiry date which is stated on the carton and foil blister (EXP). The expiry date refers to the last day of that month.
- Do not store above 25oC. Do not throw away any medicines via waste water or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.
Contents of the pack and other information
What One-Alpha contains
- The active ingredient is alfacalcidol. One-Alpha 0.25 microgram soft capsules contain 0.25 microgram of alfacalcidol in each capsule. One-Alpha 0.5 microgram soft capsules contain 0.5 microgram of alfacalcidol in each capsule. One-Alpha 1 microgram soft capsules contain 1 microgram of alfacalcidol in each capsule. •
The other ingredients are sesame oil, all-rac-α-tocopherol, gelatin, glycerol, and potassium sorbate. The 0.25 microgram capsules also contain titanium dioxide (E171). The 0.5 microgram capsules also contain titanium dioxide (E171) and red iron oxide (E172). The 1 microgram capsules also contain black iron oxide (E172) and red iron oxide (E172). You can find important information about some of the ingredients in your medicine near the end of section 2 of this leaflet.
What One-Alpha looks like and contents of the pack One-Alpha 0.25 microgram soft capsules are white capsules. One-Alpha 0.5 microgram soft capsules are red capsules. One-Alpha 1 microgram soft capsules are brown capsules. One-Alpha comes in blister packs of 30 capsules. Marketing Authorisation Holder and Manufacturer Marketing Authorisation Holder: Neon Healthcare Limited, 8 The Chase, John Tate Road, Hertford, SG13 7NN, United Kingdom Manufacturer:
LEO Pharma A/S, DK 2750, Ballerup, Denmark. CHEPLAPHARM Arzneimittel GmbH, 17489 Greifswald, Germany.
This leaflet was last revised in October 2024. ®
Registered Trade Mark
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Frequently asked questions about One-Alpha 0.5 microgram soft capsules
How do I take One-Alpha 0.5 microgram soft capsules?
One-Alpha 0.5 microgram soft capsules comes as capsule containing 0.5mcg. Always follow the dose your doctor or pharmacist has given you, and read the leaflet that comes with the medicine.
What is the active substance in One-Alpha 0.5 microgram soft capsules?
The active substance in One-Alpha 0.5 microgram soft capsules is alfacalcidol.
Are there equivalent medicines to One-Alpha 0.5 microgram soft capsules?
Medicines with the same active substance, strength and form include: AlfaD 0.5 microgram Capsule, Alfacalcidol 0.5 microgram soft capsules. They are interchangeable only if your prescriber or pharmacist says so.
Where does this information come from?
This leaflet reproduces the patient information leaflet approved for One-Alpha 0.5 microgram soft capsules, as published on the electronic medicines compendium (emc). The version printed inside your medicine’s packaging is the one that applies to you.
Can I get One-Alpha 0.5 microgram soft capsules without a prescription?
Whether a medicine is available over the counter or on prescription only depends on its licence. Check the leaflet, or ask your pharmacist — they can tell you straight away.
About this leaflet
The text above reproduces the patient information leaflet approved for this medicine, restructured for easier reading.
- Source: electronic medicines compendium (emc), Datapharm
- Active substance: alfacalcidol
- Official document: view the original leaflet on emc →
⚕For healthcare professionals — Summary of Product Characteristics (SmPC)Full SmPC: dosage, interactions, contraindications, warnings+
4.1. Therapeutic indications
One-Alpha* is indicated in all conditions where there is a disturbance of calcium metabolism due to impaired 1-α hydroxylation such as when there is reduced renal function. The main indications are:
a) Renal osteodystrophy
b) Hyperparathyroidism (with bone disease)
c) Hypoparathyroidism
d) Neonatal hypocalcaemia
e) Nutritional and malabsorptive rickets and osteomalacia
f) Pseudo-deficiency (D-dependent) rickets and osteomalacia
g) Hypophosphataemic vitamin D resistant rickets and osteomalacia
4.2. Posology and method of administration
Posology
Initial dose for all indications:
Adults and children over 20 kg bodyweight:
1 microgram/day
Elderly:
0.5 microgram/day
Neonates and premature infants:
0.05 - 0.1 microgram/kg/day
Children under 20 kg bodyweight:
0.05 microgram/kg/day
The dose of One-Alpha* should be adjusted thereafter to avoid hypercalcaemia according to the biochemical response. Indices of response include plasma levels of calcium (ideally corrected for protein binding), alkaline phosphatase, parathyroid hormone, as well as radiographic and histological investigations.
Plasma levels should initially be measured at weekly intervals. The daily dose of One- Alpha* may be increased by increments of 0.25-0.5 microgram. When the dose is stabilised, measurements may be taken every 2-4 weeks.
Most adult patients respond to doses between 1 and 3 micrograms per day. When there is biochemical or radiographic evidence of bone healing (and in hypoparathyroid patients when normal plasma calcium levels have been attained), the dose generally decreases.
Maintenance doses are generally in the range of 0.25 to 1 microgram per day. If hypercalcaemia occurs, One-Alpha* should be stopped until plasma calcium returns to normal (approximately 1 week) then restarted at half the previous dose.
(a) Renal bone disease:
Patients with relatively high initial plasma calcium levels may have autonomous hyperparathyroidism, often unresponsive to One-Alpha*. Other therapeutic measures may be indicated.
Before and during treatment with One-Alpha*, phosphate binding agents should be considered to prevent hyperphosphataemia. It is particularly important to make frequent plasma calcium measurements in patients with chronic renal failure because prolonged hypercalcaemia may aggravate the decline of renal function.
(b) Hyperparathyroidism:
In patients with primary or tertiary hyperparathyroidism about to undergo parathyroidectomy, pre-operative treatment with One-Alpha* for 2-3 weeks alleviates bone pain and myopathy without aggravating pre-operative hypercalcaemia. In order to decrease post-operative hypocalcaemia, One-Alpha* should be continued until plasma alkaline phosphatase levels fall to normal or hypercalcaemia occurs.
(c) Hypoparathyroidism:
In contrast to the response to parent vitamin D, low plasma calcium levels are restored to normal relatively quickly with One-Alpha*. Severe hypocalcaemia is corrected more rapidly with higher doses of One-Alpha* (e.g. 3-5 micrograms) together with calcium supplements.
(d) Neonatal hypocalcaemia:
Although the normal starting dose of One-Alpha* is 0.05-0.1 microgram/kg/day (followed by careful titration), in severe cases doses of up to 2 microgram/kg/day may be required. Whilst ionised serum calcium levels may provide a guide to response, measurement of plasma alkaline phosphatase activity may be more useful. Levels of alkaline phosphatase approximately 7.5 times above the adult range indicates active disease.
A dose of 0.1 microgram/kg/day of One-Alpha* has proven effective as prophylaxis against early neonatal hypocalcaemia in premature infants.
(e) Nutritional and malabsorptive rickets and osteomalacia:
Nutritional rickets and osteomalacia can be cured rapidly with One-Alpha*. Malabsorptive osteomalacia (responding to large doses of IM or IV parent vitamin D) will respond to small doses of One-Alpha*.
(f) Pseudo-deficiency (D-dependent) rickets and osteomalacia:
Although large doses of parent vitamin D would be required, effective doses of One- Alpha* are similar to those required to heal nutritional vitamin D deficiency rickets and osteomalacia.
(g) Hypophosphataemic vitamin D-resistant rickets and osteomalacia:
Neither large doses of parent vitamin D nor phosphate supplements are entirely satisfactory. Treatment with One-Alpha* at normal dosage rapidly relieves myopathy when present and increases calcium and phosphate retention. Phosphate supplements may also be required in some patients.
Method of administration
Oral.
4.3. Contraindications
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.
Hypercalcaemia, metastatic calcification.
4.4. Special warnings and precautions for use
During treatment with One-Alpha*, serum calcium and serum phosphate levels should be monitored regularly especially in children, patients with renal impairment and patients receiving high doses. PTH, alkaline phosphatase and calcium phosphates should be monitored as clinically indicated.
Hypercalcaemia might appear in patients treated with One-Alpha*. For this reason, patients should be informed about the clinical symptoms connected with hypercalcaemia. Signs of hypercalcaemia are muscle and bone pain, muscle weakness, confusion, dehydration, anorexia, fatigue, nausea and vomiting, constipation, polyuria, sweating, headache, polydipsia, hypertension and somnolence.
Hypercalcaemia can be rapidly corrected by stopping treatment until plasma calcium levels return to normal (in about one week). One-Alpha* may then be restarted at a reduced dose (half the previous dose) with monitoring of calcium.
Prolonged hypercalcaemia may aggravate arteriosclerosis, cardiac valve sclerosis or nephrolithiasis and therefore prolonged hypercalcaemia should be avoided when One- Alpha* is used in these patients. Transient or even long-lasting deterioration of kidney function has been observed. One-Alpha* should also be used with caution in patients with calcification of pulmonary tissue as this may result in cardiac disease.
In patients with renal bone disease or severely reduced renal function, a phosphate binding agent could be used simultaneously with alfacalcidol to prevent increased serum phosphate and potential metastatic calcification.
One-Alpha* should be used with caution in patients with granulomatous diseases such as sarcoidosis where the sensitivity to vitamin D is increased due to increased hydroxylation activity.
Concurrent use of digitalis glycosides in the presence of hypercalcaemia due to vitamin D administration increases the potential for cardiac arrhythmias.
One-Alpha* capsules contain sesame oil as an excipient. Sesame oil may rarely cause severe allergic reactions.
4.5. Interaction with other medicinal products and other forms of interaction
Thiazide diuretics and calcium containing preparations
Concurrent use of thiazide diuretics or calcium containing preparations may enhance the risk of hypercalcaemia. Calcium levels should be monitored.
Other vitamin D containing preparations
Concurrent use of other vitamin D containing preparations may enhance the risk of hypercalcaemia. Use of multiple vitamin D analogues should be avoided.
Anticonvulsants
Anticonvulsants (e.g. barbiturates, phenytoin, carbamazepine or primidone) have enzyme-inducing effects resulting in an increased metabolism of alfacalcidol. Patients taking anticonvulsants may require larger doses of One-Alpha.
Magnesium-containing antacids
Absorption of magnesium-containing antacids may be enhanced by One-Alpha, increasing the risk of hypermagnesaemia.
Aluminium-containing preparations
One-Alpha may increase the serum concentration of aluminium. Patients taking aluminium-containing preparations (e.g. aluminium hydroxide, sucralfate) should be monitored for signs of aluminium related toxicities.
Bile acid sequestrants
Concomitant oral administration of bile acid sequestrants such as cholestyramine may impair the intestinal absorption of oral One-Alpha formulations. One-Alpha should be administered at least 1 hour before, or 4 to 6 hours after the intake of the bile acid sequestrant in order to minimise the potential risk of interaction.
4.6. Fertility, pregnancy and lactation
Pregnancy
There is a limited amount of data from the use of alfacalcidol in pregnant women. Studies in animals have shown reproductive toxicity at high doses.
Therefore, One-Alpha is not recommended during pregnancy and in women of child- bearing potential not using contraception.
Breast-feeding
Although it has not been established, it is likely that increased amounts of 1,25- dihydroxyvitamin D will be found in the milk of lactating mothers treated with One- Alpha®*. This may influence calcium metabolism in the infant.
Consequently, breast-fed infants of alfacalcidol-using mothers should be monitored closely for hypercalcaemia.
Fertility
There are no clinical studies on the effect of One-Alpha on fertility. A pre-clinical study did not show an effect on fertility in rats.
4.7. Effects on ability to drive and use machines
Alfacalcidol has no or negligible direct influence on the ability to drive and use machines. However, the patient should be informed that dizziness may occur during treatment and take this into account while driving or using machines.
4.8. Undesirable effects
The estimation of the frequency of undesirable effects is based on a pooled analysis of data from clinical studies and spontaneous reporting.
The most frequently reported undesirable effects are various skin reactions such as pruritus and rash, hypercalcaemia, gastrointestinal pain/discomfort and hyperphosphataemia.
Renal failure has been reported post-marketing.
Undesirable effects are listed by MedDRA system organ class (SOC) and the individual undesirable effects are listed starting with the most frequently reported one. Within each frequency grouping, adverse reactions are presented in the order of decreasing seriousness.
Very common ≥1/10
Common ≥1/100 to < 1/10
Uncommon ≥1/1,000 to <1/100
Rare ≥1/10,000 to <1/1,000
Very rare <1/10,000
Not known (cannot be estimated from the available data)
Metabolism and nutrition disorders
Common:
Hypercalcaemia
Hyperphosphataemia
Psychiatric disorders
Not known:
Confusional state
Nervous system disorders
Uncommon:
Headache
Rare:
Dizziness
Gastrointestinal disorders
Common:
Abdominal pain and discomfort
Uncommon:
Diarrhoea
Vomiting
Constipation
Nausea
Skin and subcutaneous tissue disorders
Common:
Rash*
Pruritus
*Various types of rash such as erythematous, maculo-papular and pustular have been reported
Not known:
Urticaria
Musculoskeletal and connective tissue disorders
Uncommon:
Myalgia
Renal and urinary disorders
Common:
Hypercalciuria
Uncommon:
Nephrolithiasis/Nephrocalcinosis
Not known
Renal impairment (including acute renal failure)
General disorders and administration site conditions
Uncommon:
Fatigue/asthenia/malaise
Calcinosis
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard.
4.9. Overdose
Excessive intake of One-Alpha may lead to the development of hypercalcaemia, however, the effect is reversed rapidly on withdrawal.
In severe cases of hypercalcaemia general supportive measures should be undertaken: Keep the patient well hydrated by i.v. infusion of saline (force diuresis), measure electrolytes, calcium and renal function indices, assess electrocardiographic abnormalities, especially in patients using digitalis. More specifically, treatment with glucocorticosteroids, loop diuretics, bisphosphonates, calcitonin and eventually haemodialysis with low calcium content should be considered.
💬 Ask about this leaflet
Ask anything about One-Alpha 0.5 microgram soft capsules. The assistant answers only from this leaflet — if the leaflet does not cover it, it will say so. It does not give medical advice.
Answers come from the patient leaflet published on the electronic medicines compendium (emc). They are not medical advice. Ask a pharmacist or your GP if you are unsure. For urgent help call NHS 111, or 999 in an emergency.
Medicines containing Alfacalcidol
- Alfacalcidol 0.25 microgram soft capsules
- Alfacalcidol 0.5 microgram soft capsules
- Alfacalcidol 1.0 microgram soft capsules
- AlfaD 0.25 microgram Capsule
- AlfaD 0.5 microgram Capsule
- AlfaD 1 microgram Capsule
- One-Alpha 0.25 microgram soft capsules
- One-Alpha 1 microgram soft capsules
- One-Alpha 2 microgram/ml injection
- One-Alpha 2 micrograms/ml oral drops