
ergocalciferol
Vitamin D2 (ergocalciferol) is a form of vitamin D that's available both over the counter or with a prescription, depending on the dose. It's used to treat vitamin D deficiency (low vitamin D levels), including in various medical conditions, such as hypoparathyroidism (low parathyroid hormone) and rickets. Vitamin D2 (ergocalciferol) is taken by mouth, typically once a day (unlike vitamin D3, which can be prescribed once weekly at higher doses).
What is Vitamin D2 (ergocalciferol)?
What is Vitamin D2 (ergocalciferol) used for?
Low vitamin D, and certain related conditions:
- Hypoparathyroidism (low parathyroid hormone levels)
- Familial hypophosphatemia (genetic condition causing low phosphate levels)
- Vitamin D-resistant rickets (weakening of the bones caused by low vitamin D)
How Vitamin D2 (ergocalciferol) works
Vitamin D2 (ergocalciferol) is a form of vitamin D that's available as a dietary supplement. Vitamin D allows your body to absorb more calcium and phosphate, which is important to keep your bones healthy and strong. If you have problems with your parathyroid gland, your body doesn't make vitamin D very well on its own. Vitamin D2 (ergocalciferol) replaces the vitamin D your parathyroid gland isn't making.
Drug facts
| Common Brands | Vitamin D2, Drisdol |
|---|---|
| Drug Class | Dietary supplement |
| Controlled Substance Classification | Not a controlled medication |
| Generic Status | Lower-cost generic available |
| Availability | Prescription or over-the-counter |
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Side effects of Vitamin D2 (ergocalciferol)
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
See Risks and Warnings
Vitamin D2 (ergocalciferol) serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- High calcium or vitamin D blood levels: loss of appetite, nausea, weakness, weight loss, muscle aches or stiffness, constipation
- Kidney damage: a change in how much or how often you urinate, feeling tired, swelling in your legs or feet
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The following Vitamin D2 (ergocalciferol) side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
- High calcium level—increased thirst or amount of urine, nausea, vomiting, confusion, unusual weakness or fatigue, bone pain
Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):
- Constipation
- Loss of appetite
- Nausea
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Pros and cons of Vitamin D2 (ergocalciferol)
Pros
- Taken by mouth
- Available as a prescription and OTC at different doses
- A good option for vegetarians and vegans, as it's plant-based
- Only needs to be taken once a day
Cons
- Might not raise vitamin D levels as well as cholecalciferol (Vitamin D3)
- Too much vitamin D can lead to unwanted side effects
- High doses might not be a good option for pregnant or nursing mothers
- Requires regular blood tests
Pharmacist tips for Vitamin D2 (ergocalciferol)
- You can take vitamin D2 (ergocalciferol) with or without food at any time of the day. Taking it with a meal or right after you wake up can make it easier for you to remember. Try to take vitamin D2 (ergocalciferol) at the same time every day so the medication levels stay consistent in your body.
- Don't take more vitamin D2 (ergocalciferol) than instructed by your provider, since this can lead to unwanted side effects like nausea and vomiting. Contact your provider if you notice an unexplainable loss of appetite, weight loss, weakness, general aches, or stiffness. These can be signs that your dose is too high.
- Continue to take vitamin D2 (ergocalciferol) as long as your provider tells you to do so. The length of time you'll use it is different for everyone, since it depends on your condition and the results of your blood tests. Because vitamin D2 (ergocalciferol) can be used for genetic or ongoing conditions, it's possible you might need to take this medication long term or even for the rest of your life.
- Be sure to get any ordered blood tests done on time, because your lab results can affect your dose.
- Don't start taking other forms of vitamin D without first discussing it with your provider to avoid taking too much. This can include multivitamins and foods (like milk or orange juice) that have been fortified with vitamin D. Make sure your providers have a list of all your medications and supplements that you take on a regular basis, including the ones you purchase over the counter.
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Risks and warnings for Vitamin D2 (ergocalciferol)
Vitamin D2 (ergocalciferol) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
High calcium or vitamin D levels
- Risk factors: Rickets
Vitamin D2 (ergocalciferol) shouldn't be used if you have high levels of calcium or vitamin D in your blood. If you take more vitamin D2 (ergocalciferol) than the recommended or prescribed dose, it can cause calcium to build up in your blood. This can be dangerous for your kidneys. Because you need to take very high doses of this medication to treat rickets, it's much more likely for this to happen if you have rickets. Be sure to get all ordered blood tests done on time so your provider can make sure your vitamin D levels aren't too high and you're taking the correct dose. If you notice unexplained nausea that doesn't go away, a loss of appetite, weight loss, constipation, muscle pain, muscle stiffness, or a change in how much or how often you urinate, talk to your provider. These could be early signs that you're taking too much vitamin D and your calcium blood level is too high.
Vitamin D2 (ergocalciferol) dosage
Typical dosage for Vitamin D2 (ergocalciferol)
Prescription-only vitamin D2 (ergocalciferol):
Your dose can change depending on your blood vitamin D levels.
- Hypoparathyroidism: The typical dose ranges between 50,000 and 200,000 units (or international units, IU) by mouth every day, along with calcium supplementation.
- Vitamin D-resistant rickets: The typical dose ranges between 12,000 and 500,000 units (or IU) by mouth every day.
- Familial hypophosphatemia: Ask your healthcare provider to see what dose you should take.
Please note: Vitamin D2 (ergocalciferol) is available OTC in doses below 50,000 units. Ask your healthcare provider to see what dose you should take.
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Vitamin D2 (ergocalciferol) contraindications
Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Vitamin D2 (ergocalciferol) will not be safe for you to take.
- High blood calcium levels
- High blood vitamin D levels
- Malabsorption syndrome (when your body can't absorb nutrients)
What are alternatives to Vitamin D2 (ergocalciferol)?
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