Prescription Vitamin D

Vitamin D is an essential nutrient in your body for the regulation of calcium and phosphate levels. It maintains good muscle and bone health and promotes healthy teeth growth, preventing bone diseases such as osteoporosis, rickets and osteomalacia (soft bones). Vitamin D is also essential for other key processes in your immune system including your cardiovascular and skin health.

We get a small amount of vitamin D from our diet, but our main source of vitamin D comes from the sun. So during the colder months, it’s very common that many people have low levels of vitamin D, known as a deficiency.

That’s why it’s recommended that many take a vitamin D supplement regularly during the winter to keep them healthy. At HealthExpress, you can get prescription vitamin D for the treatment and prevention of vitamin D deficiency.

There are two main types of vitamin D: vitamin D3 and vitamin D2. Vitamin D3 is much more prevalent in the foods we eat (oily fish, red meats, eggs and dairy products) than vitamin D2 (ergocalciferol) and is the type that our body makes through sun exposure. Therefore, most vitamin D capsules, as well as the ones we offer at HealthExpress, contain vitamin D3.

The active ingredient in vitamin D3 capsules is cholecalciferol, which is sold under various brand names including Fultium and Colekal. Cholecalciferol is usually made under the skin when the chemical compounds in your skin (7-DHC) react with the sun’s ultraviolet B (UVB) rays. In dietary supplement form, cholecalciferol works by helping your body utilise more of the calcium from the foods you eat.

Whilst the NHS recommends that most people should take a regular dose of vitamin D during the winter, some groups of people are more likely to develop low vitamin D levels. This is because some are not able to digest or absorb the nutrients from their diet (malabsorption); eat enough of the food groups that contain vitamin D or manufacture enough vitamin D from the sun.

Those at a high risk of vitamin D deficiency include:

• older adults, especially if they are frail, housebound or in a care home
• pregnant women or women who are breastfeeding
• babies that are breastfed or are having less than 500ml of formula a day
• those with dark skin
• those who have a gastrointestinal condition such as Crohn’s disease, ulcerative colitis or celiac disease
• overweight people
• vegans or vegetarians
• those who have a family history of vitamin D deficiency
• those who have a history of liver or kidney disease
• those who are lactose or gluten intolerant
• people who take certain medications (e.g for weight loss)

Whilst suitable for the majority, certain people should not take vitamin D supplements including those who have:

• an allergy to vitamin D capsules or any of the listed ingredients
• high levels of vitamin D in your blood (hypervitaminosis D)
• high levels of calcium in your blood (hypercalcaemia) or urine (hypercalciuria)
• a history of kidney stones or serious kidney (renal) problems

Vitamin D3 supplements are measured in international units (IU), as opposed to milligrams or micrograms. 1 microgram of vitamin D is equivalent to 40IU. There are two doses of vitamin D3 (Fultium) available at HealthExpress: 800IU and 20,000IU.

The 800IU dose is suitable for vitamin D deficiency prevention (prophylaxis) which you can take throughout the year.

The 20,000IU dose, on the other hand, acts more like a vitamin D boost. It is suitable for people who think they have a deficiency, and believe they are experiencing specific symptoms of a vitamin D deficiency.

You can only buy one course of the 20,000IU capsules a year. However, you can still take the 800IU dose for year-round prevention after a course of the 20,000IU capsules.

For the 800IU dose, it is recommended you take one capsule every other day.

The 20,000IU dose is a higher dose of vitamin D, and therefore you only need to take one capsule, once a week.

You should preferably take these at the same time each week to ensure a steady dosage. Both doses should be swallowed whole with water, preferably with a main meal.

What happens if I take too much vitamin D?

Vitamin D is a fat-soluble vitamin, meaning it is stored in the body’s fatty tissue and liver. This means it stays in your body for a prolonged period of time and means you are more at risk of toxicity. It can also lead to hypercalcemia, where the serum calcium levels in your blood are too high. You may notice you feel thirsty more often or urinate more frequently. In the long run, however, it can cause much more serious conditions.

You should not exceed a daily limit of 4,000IU of vitamin D a day and you should always take the dose exactly as prescribed.

It is rare to experience side effects whilst taking vitamin D. The most common side effects are still relatively uncommon, occurring in 1 in 100 people, and are typically caused by hypercalcaemia. These symptoms include:

• loss of appetite
• constipation
• feeling sick (nausea)
• stomach ache
• feeling thirsty
• muscle weakness
• drowsiness
• confusion

For a comprehensive list of side effects, including ones that are more rare, please refer to the patient information leaflet. This is available to view and download on this page and will be delivered in the box with your medication.

If you experience any severe side effects or a potential allergic reaction, you should seek immediate medical advice.

If you have any preexisting conditions, you should also always consult your doctor or healthcare professional before taking any new supplements. In the case of vitamin D, you should especially consult your doctor if you have:

• a history of kidney damage or disease
• heart disease
• sarcoidosis - an immune disorder
• already been prescribed vitamin D or calcium supplements

It may mean you are more likely to experience adverse effects when taking vitamin D, so your doctor should assess whether they are suitable for you to take. You should also speak to your doctor if you are pregnant or breastfeeding.

Vitamin D supplements may interfere with other medications. So it’s important you disclose all the medication you are taking (including other vitamin supplements) during our online consultation, or to whomever is prescribing you. You should take caution if you are taking:

• medications for the heart (e.g digoxin)
• medications for epilepsy (e.g phenytoin or phenobarbital)
• glucocorticoids (e.g hydrocortisone or prednisolone)
• laxatives - used for constipation (e.g paraffin oil)
• cholestyramine - used to lower cholesterol
• actinomycin - used to treat some types of cancer
• imidazole antifungals, including clotrimazole and ketoconazole

This is because some of these medications, when taken with vitamin D3, can affect the metabolism or the efficacy of vitamin D supplements as well as affect your calcium levels.

You can buy prescription-only vitamin D, which is not available to purchase anywhere without a prescription, here at HealthExpress. You can purchase either the 800IU or 20,000IU dose, prescribed by one of our doctors, to treat and prevent seasonal vitamin D deficiency. You don’t need a vitamin D test, all you need to do is fill out a quick online consultation detailing your medical history. Once reviewed and approved by one of our registered doctors, our pharmacy will dispatch and dispense your medication with free next-day delivery.