Vitamin D3 injections are typically used when:

Severe deficiency: Blood 25(OH)D levels < 10 ng/mL

Malabsorption disorders: Such as celiac disease, Crohn’s, or post-bariatric surgery

Liver/kidney disease: Impaired vitamin D metabolism

Non-compliance with oral supplements

Certain elderly or disabled populations

Rapid repletion is needed, such as in osteomalacia or symptomatic deficiency

Dosage (IU) Use Case 100,000 IU Mild deficiency

300,000 IU Moderate deficiency Or single loading use

600,000 IU Severe deficiency Under specialist Supervision

Common (rare overall):

Injection site pain

Mild fever or flu-like symptoms

Rare but serious:

Vitamin D toxicity (with excessive dosing):

Nausea, vomiting

Constipation

Kidney stones or failure

Hypercalcemia (elevated calcium)

Allergic reactions (rare)

While injections help treat deficiency, ongoing sun exposure (15–30 minutes/day) and vitamin D-rich foods (like salmon, fortified dairy, egg yolks) are still important for maintenance.

Diarrhea

Nausea/vomiting

Headache

Rash

Injection site inflammation

Serious:

Seizures (especially with high doses or renal failure)

Anaphylaxis

Clostridioides difficile infection

Reconstitute with sterile water for injection

Use within 1 hour at room temp or store refrigerated (2–8°C) for up to 8 hours

Do not freeze

Usually comes as a vial with 1 g Meropenem powder

Accompanied by solvent or instructions for dilution

Drug Interactions

Can interact with:

Warfarin (increased bleeding risk)

ACE inhibitors/ARBs (increased risk of kidney dysfunction)

Diuretics (reduced effectiveness and kidney risk)

Lithium (increased lithium levels)

Other NSAIDs (increased risk of GI and cardiovascular side effects)

Monitoring

Blood pressure (especially in hypertensive patients)

Kidney and liver function (with long-term use)

Signs of GI bleeding or cardiovascular events

Advantages vs. Traditional NSAIDs

Lower risk of gastric ulcers and bleeding

Once-daily dosing

Good for long-term arthritis management in select patients

Disadvantages

Higher cost

Increased cardiovascular risk compared to non-selective NSAIDs

Not suitable for patients with heart disease

Storage

Store at room temperature (15–30°C), away from moisture and heat:

Keep out of reach of children

Important Notes

Use lowest effective dose for the shortest possible duration

Not for use as a first-line analgesic in general pain or fever

Always take under medical advice