Hidrosun (Calcifediol Monohydrate)

Hidrosun is indicated for several conditions related to insufficient vitamin D levels and calcium metabolism.

• Vitamin D deficiency identified by laboratory testing.
• Hypocalcemia associated with inadequate calcium absorption.
• Secondary hyperparathyroidism secondary to chronic kidney disease.
• Maintenance of bone health in adults at risk of osteopenia.
• Support of calcium and phosphate balance during pregnancy (under medical supervision).
• Adjunct therapy for patients on long‑term glucocorticoids.

• Calcifediol monohydrate is the 25‑hydroxy form of vitamin D. After oral absorption it is rapidly converted in the liver to calcitriol, the hormonally active 1,25‑dihydroxyvitamin D. Calcitriol binds to the nuclear vitamin D receptor (VDR) in target cells of the intestine, kidney and bone, regulating transcription of genes that increase intestinal calcium and phosphate transport and promote bone mineralization. The increased serum calcium stimulates feedback mechanisms that limit excess production of active vitamin D.

Adverse reactions to Hidrosun are generally infrequent, but they can range from mild to serious.

Common

• Mild gastrointestinal discomfort, such as nausea, abdominal cramping, or transient diarrhea.
• Headache or dizziness that resolves without medical intervention.
• Asymptomatic increase in serum calcium detected on routine laboratory testing.
• Generalized fatigue or weakness that improves with dose adjustment.

Serious

• Persistent hypercalcemia that may cause kidney stone formation or renal impairment.
• Severe hypersensitivity reactions, including urticaria, angioedema, or anaphylaxis.
• Cardiac arrhythmias or conduction abnormalities linked to markedly elevated calcium levels.
• Ectopic calcification of soft tissues, including vascular or cardiac valve calcification.

Before using Hidrosun, certain conditions and situations require careful consideration to minimize risk.

• Assess baseline serum calcium, phosphate, and vitamin D levels prior to initiation.
• Use with caution in patients who have a history of hypercalcemia or kidney stones.
• Adjust dose or avoid use in individuals with severe renal impairment (eGFR <30 mL/min/1.73 m²).
• Monitor calcium and renal function regularly during long‑term therapy.
• Pregnant or breastfeeding women should consult a healthcare professional before use.
• Concomitant use of high‑dose calcium or vitamin D supplements may increase risk of hypercalcemia.
• Discontinue if signs of allergic reaction or unexplained persistent hypercalcemia appear.

Hidrosun can interact with other medicines, affecting calcium balance or vitamin D metabolism.

Avoid

• High‑dose vitamin D analogues (e.g., calcitriol, alfacalcidol) that may cause additive hypercalcemia.
• Thiazide diuretics, which reduce urinary calcium excretion and raise serum calcium.
• Lithium therapy, which can alter calcium homeostasis and increase risk of hyperparathyroidism.

Use with caution

• Calcium‑containing antacids or supplements; monitor calcium levels.
• Bisphosphonates or denosumab; assess bone turnover markers.
• Corticosteroids; may increase vitamin D requirements.
• Loop diuretics; may affect calcium excretion.
• Anticonvulsants (e.g., phenytoin, phenobarbital) that accelerate vitamin D metabolism.