How It Works
Vitamin D2 (ergocalciferol) works by helping your body absorb more calcium, which is essential for bone, brain, and immune health. It also helps maintain healthy phosphate levels.
| Quick Facts | |
|---|---|
| Common Brands | Drisdol, Ergocal |
| Drug Class | Dietary supplement |
| Generic Status | Generic is available |
| Availability | Prescription only |
Dosing
Ergocalciferol (vitamin D2) capsules are taken orally on a weekly or daily basis. The dosage depends on the severity of your vitamin D deficiency. For example:
- Hypoparathyroidism: The recommended dose can range from 50,000 to 200,000 international units (IU) daily, typically alongside calcium supplementation.
- Vitamin D-resistant rickets: The recommended dose can range from 12,000 to 500,000 IU daily.
Note: Dosing information below is educational only. Your prescribing physician will determine your specific dose based on your individual health needs. Always follow your healthcare provider’s instructions for exact dosing.
Uses
FDA-Approved Uses
Ergocalciferol (vitamin D2) capsules are FDA-approved to treat hypoparathyroidism (low parathyroid hormone levels), vitamin D-resistant rickets, and familial hypophosphatemia (genetically low phosphorus levels).
Off-Label Uses
You may see ergocalciferol (vitamin D2) capsules prescribed for uses that are not “FDA-approved.” This is a common and legal practice called “off-label” prescribing, where a doctor uses their clinical judgment to prescribe a drug for a different (but well-researched) purpose.
Ergocalciferol (vitamin D2) capsules may be used off-label for other health conditions related to low vitamin D levels.
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Side Effects
Like all medications, ergocalciferol (vitamin D2) capsules can cause side effects. Some common side effects may improve over time as your body adjusts to the medication. Other side effects may be serious and require medical attention.
Common Side Effects
- Nausea
- Vomiting
- Constipation
- Loss of appetite
- Weakness
- Tiredness
- Weight loss
- Headache
- Metallic taste
Serious Side Effects
Serious side effects are rare, but it’s important to know what to look for if they do occur. Stop using ergocalciferol (vitamin D2) capsules and call your doctor immediately if you experience:
- Severe allergic reactions: Symptoms include swelling of the face, lips, tongue, or throat; difficulty breathing or swallowing; racing heart; severe rash or itching; and/or fever.
- High calcium levels (hypercalcemia): Vitamin D supplementation can cause calcium levels to get too high. Symptoms include increased thirst or urination, nausea, vomiting, confusion, bone pain, weakness, weight loss, and muscle aches or stiffness.
- Kidney damage: Taking too much vitamin D may cause kidney problems. Symptoms include changes in urination amount or frequency, tiredness, and swelling in the legs or feet.
Call your doctor immediately if you experience any concerning or prolonged symptoms.
Pharmacist Tips
Take With A Fat-Containing Meal Or Snack
Ergocalciferol capsules can be taken with or without food, but taking it with fat-containing food (like milk, yogurt, or cheese) helps your body absorb it more efficiently.
Take Your Dose Consistently
Taking the medication at the same time can help maintain steady vitamin D levels.
Keep Up With Blood Work
Keep all appointments to have your blood checked. Regular lab work helps your doctor ensure you are getting enough vitamin D without your calcium levels getting too high.
Get Enough Calcium
For the medication to work effectively, you need to maintain an adequate calcium intake. Your provider will recommend ways to ensure you get enough calcium from food or supplements.
Don’t Take Extra Vitamin D
To avoid levels from getting too high, don’t start taking other forms of vitamin D (such as multivitamins or fortified foods) without checking with your provider first.
Store At Room Temperature
Ergocalciferol (vitamin D2) capsules should be stored at 68°F to 77°F (20°C to 25°C) in a cool, dry place away from light.
Tell Your Provider If You’re Pregnant Or Breastfeeding
It is not known if ergocalciferol can affect pregnancy, but it does pass into breast milk. Tell your healthcare provider if you are pregnant, breastfeeding, or planning to be, so they can advise whether this medication is safe for you to use.
Try To Avoid Missing A Dose
If you miss a dose of ergocalciferol (vitamin D2) capsules, take it as soon as you remember, unless it is almost time for your next dose. In that case, skip the missed dose and take your next dose as scheduled. Do not take double or extra doses to make up for a missed one.
Drug Interactions
Certain medications and substances can interact with ergocalciferol, potentially altering how it works or increasing the risk of side effects. For example:
- Orlistat (Alli, Xenical): This medication should not be used with ergocalciferol.
- Cholesterol medications: Ergocalciferol can interact with statins like atorvastatin (Lipitor) or rosuvastatin (Crestor), and other cholesterol medications like cholestyramine, colesevelam, or colestipol.
- Thiazide diuretics: Taking ergocalciferol with certain blood pressure medications, such as hydrochlorothiazide, chlorthalidone, or indapamide, can increase the risk of high calcium levels.
- Seizure medications: Medications like phenytoin or fosphenytoin may interact with ergocalciferol.
- Antacids: These medications may interact with calciferol.
- Mineral oil: This can interfere with the absorption of fat-soluble vitamins like vitamin D.
- Magnesium or phosphorus supplements: These supplements may interact with ergocalciferol.
- Rifampin: This medication may interact with ergocalciferol.
Always give your doctor and pharmacist a complete list of all your medications, vitamins, and supplements to check for potential interactions.
FAQs
Why is my prescription dose so incredibly high compared to the vitamins I see at the grocery store?
Over-the-counter vitamin D2 is typically available in doses below 50,000 units. Prescription doses are much higher (ranging from 12,000 up to 500,000 units) because they are designed to treat severe deficiencies or specific medical conditions like rickets and hypoparathyroidism.
Do I take ergocalciferol capsules every single day?
It depends on your condition and your provider’s instructions. While the 50,000 unit dose is typically taken once weekly, it is sometimes prescribed to be taken more frequently for certain conditions.
What is the exact difference between vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol)?
Ergocalciferol (vitamin D2) is the plant-derived, inactivated form of the vitamin. Cholecalciferol (vitamin D3) is the natural form produced in the skin via sunlight and found in certain foods. Studies suggest vitamin D3 may be more potent and stable.
Do I have to take an ergocalciferol pill with a meal containing fat?
You can take ergocalciferol capsules with or without food. However, because it is a fat-soluble vitamin, taking it with a snack or meal that contains fat helps your body absorb the medication more effectively.
Is it true that ergocalciferol is vegan-friendly, unlike other vitamin D pills?
Yes, ergocalciferol is a plant-based medication, making it a good option for people who follow vegetarian or vegan diets.
How long does it usually take for my vitamin D levels to return to normal?
The timeline varies for everyone based on their specific condition. It is important to note that the effects of vitamin D supplementation can remain in your system for over 2 months after you stop taking ergocalciferol.
Do I still need to go out in the sun to get vitamin D if I am taking this prescription?
Ergocalciferol is generally prescribed for people who do not get enough vitamin D from their diet or sun exposure. Talk to your provider about balancing natural exposure with your supplement.
Is it safe to drink alcohol while taking ergocalciferol?
It is currently unknown if drinking alcohol directly interacts with the medication itself. However, if your vitamin D levels are already low, it is best to avoid alcohol, as studies show it affects the body’s ability to absorb essential nutrients, including vitamin D.
What should I do if I completely forget what day I was supposed to take my pill?
If you miss a dose of ergocalciferol, take it as soon as you remember. However, if it is almost time for your next scheduled dose, simply skip the missed one. Do not take double or extra doses to make up for a missed pill.
Will taking ergocalciferol capsules help with my depression or seasonal affective disorder (SAD)?
Low vitamin D levels can lead to various health issues, including mood problems. Ergocalciferol is effective at treating low vitamin D levels, which may help support overall wellness if a deficiency is present.
Can this vitamin interact with my blood pressure medications or heart drugs?
Yes, ergocalciferol can interact with thiazide diuretics (such as hydrochlorothiazide, chlorthalidone, or indapamide), which are commonly used to lower blood pressure.
Is there a warning about taking ergocalciferol alongside certain weight-loss or cholesterol drugs?
Yes. The medication can interact with weight-loss drugs like orlistat, statin medications like atorvastatin or rosuvastatin, and other cholesterol medications like cholestyramine or colestipol.
Is it safe to take ergocalciferol if I am pregnant or breastfeeding?
It is currently unknown if or how ergocalciferol might affect pregnancy or an unborn baby. The medication does pass into breast milk. Consult your healthcare provider before taking it if you are pregnant or breastfeeding or planning to become pregnant.
Does ergocalciferol expire?
Yes, ergocalciferol (vitamin D2) capsules expire. Check the expiration date on the prescription label or medication packaging.
Comparable Medications
Ergocalciferol (vitamin D2) capsules, cholecalciferol (Vitamin D3), or calcitriol (Rocaltrol)?
There are several medications that your doctor can prescribe in place of ergocalciferol (vitamin D2) capsules. Here are a few possible alternatives below.
Cholecalciferol (Vitamin D3) Capsules
From $22.99
A form of vitamin D3 used to treat low vitamin D levels that is available in over-the-counter and prescription strengths.
Calcitriol Capsules
From $27.99
A prescription form of vitamin D used to treat low calcium levels.
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Important: Information on this page is for educational purposes only. Prescribing decisions are made by independent, licensed providers. TelyRx operates technology-enabled pharmacies and a telehealth platform that connects patients with board-certified licensed providers. Prescriptions, when provider-approved and issued, are filled and shipped by TelyRx-affiliated pharmacies. We do not employ physicians or make prescribing decisions. Learn more about our editorial standards here.