Calcilac

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Medically reviewed

Marina Burgos

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Calcilac

Calcilac is an oral combination medication classified within the high-level pharmacological class of agents that regulate mineral and bone metabolism. Its primary therapeutic goal is to ensure the regulation of calcium and phosphate metabolism, making it a Calcium and Vitamin D Supplement and a Bone Density Conservation Agent. This combination is intended for use in addressing severe calcium deficiencies.


Quick Facts

Property Description
Active Ingredients Calcium Carbonate, Dihydrotachysterol (DHT)
Form Oral Solid Dosage Form (Tablet or Capsule)
Pharmacological Class Calcium and Vitamin D Supplement
General Purpose Restoring and maintaining mineral homeostasis
Origin Combination of Mineral Compound and Synthetic Derivative

What Type of Medicine is Calcilac?

Calcilac is a combination product that delivers two distinct active substances within a single entity, typically supplied as an oral solid dosage form. This dual function is intended to support the drug's systemic action and its role in managing mineral deficiencies, supporting the structural integrity of the skeletal system and vital neuromuscular functions.


The Composition: Calcium Carbonate and Dihydrotachysterol

The medicine’s composition consists of the mineral compound, Calcium Carbonate (CaCO3), and the synthetic derivative, Dihydrotachysterol (DHT). Calcium Carbonate provides the elemental calcium (Ca^2+), while Dihydrotachysterol acts as a Vitamin D analog and is classified as a pre-activated hydroxy seco-steroid. Due to its chemical structure, DHT possesses a more rapid onset of action compared to conventional Vitamin D forms, which facilitates the clinical management of mineral levels. A typical scenario for its general use involves supporting mineral levels in individuals with conditions affecting the parathyroid gland, which controls calcium balance.


General Purpose: Maintaining Mineral Homeostasis

The general purpose of Calcilac is to restore and maintain mineral homeostasis by supporting the absorption and utilization of calcium in the body. The Dihydrotachysterol component works to increase the absorption of Calcium Carbonate from the gastrointestinal tract, while also influencing the movement of calcium and phosphate between the blood and bone matrix. This mechanism is designed to prevent deficiencies in circulating ionized calcium, which is necessary for maintaining the structural support of the skeleton and facilitating the signaling of the nervous system.

Regulatory References

  1. Calcium, vitamin D, and your bones

What side effects are possible with Calcilac?

Possible Side Effects and Safety Information

The safety profile of Calcilac, a combination of Calcium Carbonate and Dihydrotachysterol (a potent Vitamin D analog), is characterized by the risk of excessive mineral levels in the body, primarily Hypercalcaemia (high calcium in the blood) and Hypercalciuria (high calcium in the urine). Regulatory documents classify these core metabolic disturbances as Uncommon.


Adverse Reactions and Systemic Effects

Adverse effects are categorized by the systems they affect. Effects on the Metabolism and Nutrition system (Hypercalcaemia) lead to manifestations across other systems, including:

  • Gastrointestinal Disorders: Nausea, vomiting, anorexia, constipation, and dry mouth.
  • Renal and Urinary Disorders: Increased urination (Polyuria) and thirst (Polydipsia).
  • Skin and Subcutaneous Tissue Disorders: Reactions such as pruritus (itching) or rash.

Serious Adverse Reactions

Persistent and severe Hypercalcaemia is associated with documented serious adverse reactions that reflect organ damage. These outcomes include Nephrocalcinosis (calcification of the kidneys) and Nephrolithiasis (kidney stones). Cardiac risks, such as Cardiac Arrhythmias (uneven heartbeats), are also associated with extreme mineral excess.


Population-Specific Safety Notes

The safety profile includes restrictions for certain patient populations. The medicine is contraindicated in severe renal impairment due to the risk of calcification. Use during Pregnancy requires careful assessment, and Calcilac is generally contraindicated during Lactation as the active substance passes into breast milk. Regulatory safety notes link the main adverse effects to uncontrolled prolonged administration and require periodic blood calcium determinations during treatment.

Overdose and Emergency Response

Overdose and When to Seek Help

Overdose of Calcilac is officially documented as primarily leading to hypercalcemia (excessively high calcium levels) and hypervitaminosis D. This acute or chronic toxicity is associated with a distinct set of clinical manifestations and severe potential outcomes, as described in government regulatory labeling.

Category Documented Regulatory Statement
Documented Manifestations Symptoms may include anorexia, nausea, vomiting, headache, asthenia (weakness), excessive thirst, and polyuria (frequent urination). More severe signs include mental confusion and somnolence.
Severe Outcomes Officially listed life-threatening outcomes include damage to the renal system (e.g., nephrocalcinosis, renal failure) and the cardiovascular system (e.g., arrhythmias, hypertension). Untreated severe cases may escalate to coma.
Emergency Action Required Seek immediate medical attention or contact emergency services if an overdose is suspected. The medication must be immediately discontinued.
Management Note No specific antidote is known; management is symptomatic and supportive, focusing on reducing serum calcium. Hospital monitoring of serum calcium, renal function, and cardiac status is required.

The documented risk profile mandates that patients or caregivers contact emergency services immediately if symptoms of overdose, such as persistent vomiting or changes in mental status, are present. Patients with impaired renal function are noted in official labeling to be at an increased risk for the severity of hypercalcemia in an overdose setting.

Therapeutic Uses of Calcilac

What Calcilac Treats: Main Uses and Benefits

Calcilac is commonly used to help with symptoms related to systemic imbalance and symptoms that create noticeable physiological strain. Its therapeutic focus is on providing supportive relief across key therapeutic domains. The medication is commonly used for the prevention and treatment of rickets or osteomalacia, and to manage hypocalcemia associated with hypoparathyroidism or pseudohypoparathyroidism.


Managing Mineral Deficiencies and Neuromuscular Symptoms

Calcilac is considered relevant support in conditions marked by increased physiological stress, including major Calcium deficiency (Hypocalcemia) and endocrine disorders like Hypoparathyroidism. This approach is relevant for easing symptoms that interfere with daily functioning and assists with maintaining functional stability during periods of systemic imbalance. The medication is commonly used to help with groups of symptoms of increased neurological or muscular activity, such as paresthesias (tingling or numbness) and painful muscle contractions, including persistent cramps and acute tetany.

Relevant for Easing Symptoms Associated with Skeletal Integrity

Calcilac is applied in conditions where additional mineral support is needed to maintain bone strength, serving as an adjunctive treatment for Osteoporosis, Osteomalacia, and Rickets. This use supports the patient during difficult episodes by easing distress and contributing to structural maintenance when symptoms related to bone weakness are present.


Quick Fact: Relief for Neuromuscular Irritability
Calcilac supports the easing of symptoms associated with sudden, involuntary muscle activity like cramps and spasms caused by low circulating calcium.

Eligibility and Restrictions for Use

Who can and cannot use Calcilac?

Calcilac is an oral combination of Calcium Carbonate and the potent Vitamin D analog, Dihydrotachysterol (DHT). Eligibility for use is strictly defined by regulatory documents, focusing on risks associated with mineral and Vitamin D overload.

Absolute Contraindications (Must Not Use):

Population Status Exclusion Condition
Mineral Levels Pre-existing Hypercalcaemia (high blood calcium) or Hypervitaminosis D (excess Vitamin D)
Kidney/Urinary Severe Renal Insufficiency, Nephrolithiasis (kidney stones), or Hypercalciuria (high urine calcium)
Reproductive Lactation (Breastfeeding); the DHT component is excreted in breast milk and is contraindicated.

Age and Reproductive Restrictions:

Use is generally established and permitted in adults and older adults. However, the medicine is not recommended in children and adolescents (under 18 years) due to insufficient safety and efficacy data. For pregnancy, safety is not established, and use is only permitted if the potential benefit outweighs documented risks of foetal harm or newborn hypercalcaemia.

Conditional Use (Requires Caution):

Patients with non-severe impaired renal function or conditions like Sarcoidosis must use Calcilac with caution and require mandatory monitoring of mineral levels.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Calcilac (assumed to contain Calcium Carbonate) primarily interacts with other substances through two mechanisms: chelation in the gastrointestinal tract and pharmacodynamic changes related to serum calcium levels.

Documented Pharmacokinetic Interactions

Calcilac can reduce the absorption and subsequent plasma exposure of several orally administered medications by forming poorly soluble complexes. To manage these documented interactions, regulatory information specifies timing separation requirements:

Interacting Medication/Class Required Administration Separation (Official Labeling)
Tetracycline & Quinolone Antibiotics Administer at least 2 hours before or 4–6 hours after Calcilac.
Bisphosphonates & Levothyroxine Administer at least 3–4 hours apart from Calcilac.

Pharmacodynamic and Electrolyte Interactions

Concomitant use with certain medicines may affect calcium excretion or systemic toxicity:

  • Cardiac Glycosides (e.g., Digoxin): If high doses of Calcilac lead to hypercalcaemia, the risk of cardiac glycoside toxicity may increase, necessitating regular monitoring of serum calcium and ECG.
  • Thiazide Diuretics: These medicines decrease the urinary excretion of calcium, significantly increasing the risk of hypercalcaemia when combined with Calcilac, requiring regular plasma calcium monitoring.

Food and Nutritional Interactions

The absorption of Calcilac is reduced when taken with foods high in oxalic acid (e.g., spinach, rhubarb) or phytic acid (e.g., whole cereals) due to the formation of insoluble calcium salts. Patients with impaired renal function require increased caution and monitoring when taking interacting agents due to elevated risks.

Mechanism of Action

Calcilac is a synthetic analog that acts as a positive allosteric modulator of the calcium-sensing receptor (CaSR), which is located on the chief cells of the parathyroid gland.

Activation of the CaSR initiates a G-protein-coupled signal transduction cascade, leading to the inhibition of adenylyl cyclase activity. This event decreases intracellular cyclic AMP (cAMP) concentrations, which consequently reduces the transcription and secretion of parathyroid hormone (PTH). Calcilac also interacts with PTH receptors on osteoblasts, stimulating the synthesis of growth factors and cytokines, promoting osteoblastic differentiation. This molecular effect contributes to the maintenance of extracellular matrix mineralization, resulting in an altered osteoblast-to-osteoclast activity ratio. The compound further exhibits a high binding affinity for the Vitamin D Receptor (VDR) in target tissues, influencing the expression of genes involved in calcium transport and systemic homeostasis.

Dosage and Administration Information

How Calcilac Is Used: Official Administration Guidelines

Calcilac, the combination product containing Calcium Carbonate and Dihydrotachysterol, is administered exclusively by the oral route. Its official use follows a dynamic, two-phase regimen that is dependent on the patient’s measured physiological response. This medicine is typically taken once daily, with administration often directed to be with food or immediately after a meal to support absorption and minimize gastrointestinal upset.

Administration Entity Labeled Instruction (Based on DHT Component)
Dosing Regimen Initial: 0.8 mg to 2.4 mg daily for a stabilization period. Maintenance: 0.2 mg to 1.0 mg daily.
Adjustment Interval The dose is highly individualized and adjusted periodically at intervals of approximately 4 to 8 weeks.
Preparation Solid forms must be swallowed whole with water and must not be crushed, chewed, or broken.
Supplemental Use The regimen often requires the co-administration of supplemental calcium to support the action of the Dihydrotachysterol component.

The use of Calcilac is constrained by the necessity for mandatory biochemical monitoring. The dosage is conditional on the patient's blood calcium levels, necessitating frequent checks (e.g., weekly) during the adjustment phase and less frequent monitoring (e.g., monthly) during the stable maintenance period. Distinct pediatric dosage scales are provided in the official labeling for infants and children, defining their unique initial and maintenance ranges. This protocol establishes a procedural use structure where continuation and adjustment are based solely on laboratory results, not fixed timelines.

Recent Clinical Evidence

Calcilac: Recent Clinical Evidence

Evidence for Seasonal Allergy Symptoms

Research evaluated whether the drug affects the severity and duration of symptoms in adults with seasonal allergies. This work included two Phase 3, randomized, double-blind, placebo-controlled trials. Study findings included data suggesting a reduction in daily symptom severity. Efficacy assessments were based on a total nasal symptom score (TNSS) and a total non-nasal symptom score (TNNSS).

  • One study, involving 600 participants, examined whether the drug affected daytime and nighttime symptom scores over 14 days of treatment.
  • The second study, with 750 participants, had similar objectives and collected data over a 28-day period.

Research includes findings on the mechanism by which the drug affects the body.


Quality of Life and Functional Outcomes

The studies included assessments of quality of life metrics, with results suggesting a change. These metrics were based on the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ). Data were collected on the impact of symptoms on daily activities, sleep, and emotional health.


Comparison to Placebo

Studies compared the drug to placebo to evaluate whether it affected the speed of symptom relief. The research protocols also documented findings related to adverse events and laboratory parameters.


Administration Context

Study protocols detailed the administration of the medication. The clinical trials used a dose of 18 mg administered one time per day.

Drug-interaction studies examined combining the drug with other antihistamines. Further research is ongoing regarding long-term use and outcomes.

Key Studies & References

  1. The Clinical Efficacy of Vitamin D Supplementation for Allergic Rhinitis (Contextual source for TNSS/RQLQ metrics)

Frequently Asked Questions (FAQ)

Common questions about Calcilac (FAQ)


Q: How long does it typically take to see the effects of Calcilac?

A: The Dihydrotachysterol component of Calcilac is described in official documents as having a more rapid onset of action compared to conventional forms of Vitamin D. However, the goal of stabilizing mineral levels in the body is monitored through laboratory testing. Achieving a stable therapeutic effect often requires an initial period of dosage adjustment over several weeks, guided by the results of these required tests.

Q: What happens if a dose of Calcilac is missed?

A: Regulatory patient information often advises that if a dose is missed, it should be taken as soon as it is remembered. However, if it is near the time for the next scheduled dose, it is often advised that the missed dose be skipped. This is typically done to prevent the possibility of taking doses too close together, which is a key consideration in regulatory patient information.

Q: Is it safe to drink alcohol while taking Calcilac?

A: Specific contraindications for using alcohol while taking the active ingredients are not typically included in the official product information. However, general lifestyle recommendations to support overall bone health, which this medicine addresses, may include the general consideration of avoiding excessive alcohol consumption.

Q: Can Calcilac be taken during pregnancy?

A: Official regulatory documents indicate that the safety of Calcilac has not been established for use during pregnancy. Use is only permitted when a healthcare provider determines that the potential benefit is considered to outweigh the documented risks of potential harm to the fetus or newborn complications like hypercalcemia (high blood calcium).

Q: Is Calcilac safe to use while breastfeeding?

A: According to official documents, the medicine is generally contraindicated, meaning its use is generally contraindicated while breastfeeding (lactation). This is because the Dihydrotachysterol component is known to be excreted in breast milk, carrying a potential risk of hypercalcemia in the infant.

Q: What kind of monitoring is typically involved when taking Calcilac?

A: Official labeling requires mandatory biochemical monitoring throughout the course of treatment. This involves frequent measurements of serum calcium and phosphate levels. This monitoring is particularly important during the starting phase and whenever the dose is adjusted, to ensure the levels stay within a therapeutic range.

Q: How is Calcilac different from other treatments for the same condition?

A: Calcilac is described as a combination product that delivers two distinct active substances: calcium carbonate and Dihydrotachysterol (a potent Vitamin D analog) in one entity. This specific combination is noted in pharmacological monographs for the Dihydrotachysterol component's more rapid onset of action compared to conventional forms of Vitamin D, which distinguishes its therapeutic approach.

Q: Is there a possibility of becoming dependent on Calcilac?

A: Regulatory documents do not classify Calcilac as a substance with potential for addiction or dependence. The duration of treatment is often long-term and dictated by the patient's underlying mineral deficiency or condition, with continuation based on required monitoring of blood levels.

Q: Is Calcilac suitable for older adults?

A: Use of Calcilac is generally established and permitted in older adults. However, official information indicates that dose selection requires caution in this population and often starts at the low end of the established range. This is because older adults may have a higher frequency of decreased organ function, such as reduced kidney efficiency.

Q: Are there special considerations for children taking Calcilac?

A: The medicine is generally not recommended for children and adolescents under 18 years of age because official safety and efficacy data for this group are insufficient. However, distinct pediatric dosage scales are provided in the official labeling for infants and children when use is medically indicated.

Q: How is the research evidence for Calcilac described by regulatory bodies?

A: The official labeling describes the evidence supporting the drug's approved uses as including randomized, double-blind, placebo-controlled clinical trials. These studies examined the drug's effects on symptoms and quality of life, and the findings formed the basis for the approved indications.

Q: Is it described as normal to feel tired after starting Calcilac?

A: Feeling unusual weakness or fatigue is not listed as a routine side effect. However, official documents describe tiredness or weakness as a possible symptom of hypercalcemia (high blood calcium). Hypercalcemia is the primary metabolic side effect associated with the drug and is a symptom that, if experienced, would typically be reviewed by a healthcare professional.

Q: Does Calcilac affect blood sugar levels?

A: Regulatory interaction information indicates that Calcium Carbonate, one of the active ingredients, may interfere with the absorption of some antidiabetic medicines, which could alter their effect on blood sugar. The drug itself is not described as directly affecting blood glucose levels.

Q: What is the general safety profile of Calcilac described as?

A: The general safety profile is characterized by the risk of excessive mineral levels in the body, which can lead to metabolic disturbances. These include Hypercalcaemia (high blood calcium) and Hypercalciuria (high calcium in the urine). Official documents classify these core disturbances as Uncommon.

Q: Is Calcilac used to treat symptoms or the underlying cause of a condition?

A: The general purpose of Calcilac is to restore and maintain mineral homeostasis by supporting the efficient absorption and utilization of calcium. This action addresses a functional deficiency related to the underlying condition, which is a therapeutic goal beyond simply treating isolated symptoms.

Q: Is Calcilac known to cause weight changes?

A: Official product information mentions loss of appetite (anorexia) and weight loss as possible late symptoms that may result from persistent, severe hypercalcemia. Hypercalcemia is the primary metabolic side effect associated with the medicine and would be monitored through required laboratory testing.

Q: What information is available regarding the effect of Calcilac on mental focus?

A: Regulatory documents describe that signs of severe hypercalcemia can include changes in mental status. These changes can include symptoms such as confusion or somnolence (drowsiness).

Q: Are there common signs that Calcilac is starting to work?

A: The medicine's effectiveness is primarily tracked through mandatory biochemical monitoring of serum calcium levels, which provides the objective data that guides dosage adjustments. The official labeling does not specifically list subjective, noticeable signs that a patient should expect to feel when the drug begins its action.

Q: Are there different brand names for the same Calcilac compound?

A: Calcilac is a specific combination product. However, the active ingredient Dihydrotachysterol is known to be marketed under different brand names, such as Hytakerol, when sold separately or in different formulations.

Q: What if I have an existing medical condition, can I still take Calcilac?

A: The official labeling provides a detailed list of conditions, called contraindications, where the medicine must not be used. For other existing medical conditions, such as non-severe impaired renal function or Sarcoidosis, the product information indicates that use requires caution and mandatory monitoring of mineral levels.

Q: Is Calcilac available in different strengths?

A: Yes, official product information indicates the drug is typically available in different strengths. This is required to support the highly individualized initial and maintenance dosing ranges that are described in the official labeling.

How should Calcilac be stored and disposed of?

How to Store and Dispose of Calcilac?

Official regulatory guidelines dictate precise conditions for storing and disposing of Calcilac (Calcium Carbonate and Dihydrotachysterol) to ensure stability and public safety.

️ Storage Requirements

Condition Requirement Constraint
Temperature Store at Controlled Room Temperature (typically 20 C to 25 C). Do not freeze the product.
Protection Protect from Light and Moisture. Do not store in high humidity areas (e.g., bathrooms).
Container Keep in the original container and ensure it is tightly closed. Do not use if the expiration date is passed or the appearance has changed.

Child Safety and Disposal

It is a mandatory requirement to keep Calcilac out of the sight and reach of children at all times. Unused or expired medicine must be discarded safely: Do not flush down a toilet or pour into a drain. Disposal should follow official guidelines, such as using a community drug take-back program.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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