Invita D3 (Colecalciferol)

• Invita D3 (colecalciferol) is used to address conditions related to insufficient vitamin D and bone health.
• Vitamin D deficiency: restores adequate serum 25‑hydroxyvitamin D levels to support calcium homeostasis.
• Osteomalacia and rickets prevention: provides the necessary vitamin D to promote proper bone mineralization in at‑risk populations.
• Bone health support: contributes to maintenance of normal bone density and reduces risk of fractures in adults.

• Colecalciferol is converted in the liver to 25‑hydroxyvitamin D, which is further hydroxylated in the kidney to the active hormone 1,25‑dihydroxyvitamin D. The active form binds to vitamin D receptors in intestinal cells, enhancing transcription of calcium‑binding proteins and increasing intestinal absorption of calcium and phosphate, thereby facilitating bone mineralization and maintaining serum calcium levels.

Colecalciferol may be associated with a range of adverse reactions, most of which are mild and reversible.

Common Side Effects

• Nausea: mild stomach upset that resolves after continued use.
• Constipation: occasional difficulty passing stool.
• Hypercalcemia symptoms: mild fatigue or headache.
• Dry mouth: transient sensation of oral dryness.
• Muscle cramps: occasional mild cramping.

Serious or Rare Side Effects

• Hypercalcemia: severe elevation of blood calcium causing confusion or cardiac arrhythmia.
• Kidney stones: formation of calcium‑containing calculi in the urinary tract.
• Allergic reaction: rash, itching, or swelling of the face, lips, or tongue.
• Severe vomiting: persistent vomiting requiring medical attention.

Before using Invita D3, consider the following precautions to ensure safe and effective therapy.

• Assess baseline vitamin D status: measure serum 25‑hydroxyvitamin D levels to guide supplementation.
• Monitor calcium levels: periodic testing recommended for patients at risk of hypercalcemia.
• Adjust dose in renal impairment: patients with severe kidney disease may require lower doses.
• Caution in sarcoidosis or granulomatous disease: these conditions can increase conversion to active vitamin D.
• Avoid concurrent high‑dose calcium supplements: may exacerbate hypercalcemia risk.
• Store at room temperature: keep below 25 °C, retain in original container, protect from moisture and direct sunlight.

Colecalciferol can influence or be influenced by other medicines. Interactions are grouped by clinical significance.

Major Interactions (Avoid)

• Thiazide diuretics: may increase risk of hypercalcemia.
• Vitamin A excess: combined high intake can lead to hypercalcemia.
• Lithium: vitamin D may raise lithium levels, requiring monitoring.
• High‑dose calcium supplements: synergistic effect on calcium load.
• Antacids containing aluminum or magnesium: may reduce absorption of vitamin D.

Moderate Interactions (Monitor Closely)

• Corticosteroids: can reduce vitamin D effectiveness, may need dose adjustment.
• Anticonvulsants (e.g., phenytoin, phenobarbital): increase vitamin D metabolism, potentially lowering levels.
• Orlistat: may decrease absorption of fat‑soluble vitamins including vitamin D.
• Cholestyramine: can bind vitamin D and reduce its bioavailability.
• Bisphosphonates: concurrent use may affect calcium balance, monitor serum calcium.