Usage
Calcium citrate is primarily prescribed to prevent or treat hypocalcemia (low blood calcium levels) in individuals with insufficient dietary calcium intake. It is also used to manage conditions resulting from hypocalcemia, including:
- Osteoporosis (bone loss)
- Osteomalacia/rickets (weak bones)
- Hypoparathyroidism (decreased parathyroid gland activity)
- Latent tetany (a specific muscle disease)
It’s also prescribed to ensure adequate calcium intake in specific populations like pregnant or breastfeeding women, postmenopausal women, and individuals taking certain medications (e.g., phenytoin, phenobarbital, or prednisone). Calcium citrate may help prevent renal calculi formation by binding oxalate in the gut.
Pharmacological Classification: Calcium supplement, mineral supplement
Mechanism of Action: Calcium is essential for various physiological processes, including nerve and muscle function, bone health, and blood clotting. Calcium citrate provides a readily absorbable source of calcium, increasing serum calcium levels and mitigating the effects of hypocalcemia.
Alternate Names
Calcium citrate is sometimes referred to as tricalcium dicitrate.
Brand Names: Citracal, Caltrate, Os-Cal, Oysco, Cal-Cee, Cal-C-Cap, Cooper Complete® Calcium Citrate.
How It Works
Pharmacodynamics: Calcium is a crucial component of bone structure and plays a vital role in nerve transmission, muscle contraction, and blood coagulation. It also acts as a cofactor for various enzymes. Calcium citrate supplementation replenishes calcium stores, improving bone mineral density and supporting normal physiological functions.
Pharmacokinetics:
- Absorption: Calcium citrate is absorbed in the small intestine, enhanced by the presence of food.
- Metabolism: It doesn’t undergo significant metabolism.
- Elimination: Calcium is primarily excreted renally (through the kidneys) with some fecal elimination.
Mode of Action: Calcium influences cellular processes by modulating ion channels, acting as a second messenger, and interacting with calcium-binding proteins like calmodulin. It doesn’t typically involve receptor binding, enzyme inhibition, or direct neurotransmitter modulation.
Elimination Pathways: Primarily renal excretion.
Dosage
Standard Dosage
Adults:
- RDA: 1000 mg/day (19-50 years); 1200 mg/day (women > 50 years and men > 70 years); 1000 mg/day (men 51-70 years).
- Hypocalcemia prevention: 1000 mg/day in divided doses.
- Osteoporosis prevention: 1000-1500 mg/day in divided doses.
Children:
- RDA: Varies by age (see sources).
- Hypocalcemia: Neonates: 50-150 mg/kg/day divided every 4-6 hours (max 1g/day); Children: 45-65 mg/kg/day divided every 6 hours.
Special Cases:
- Elderly Patients: May require higher doses due to reduced absorption.
- Patients with Renal Impairment: Dose adjustment based on creatinine clearance is essential. Close monitoring of calcium levels is needed.
- Patients with Hepatic Dysfunction: No specific adjustments are typically needed.
- Patients with Comorbid Conditions: Consult product information.
Clinical Use Cases
Calcium citrate is generally not indicated for acute medical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. Intravenous calcium gluconate or calcium chloride is preferred in these settings.
Dosage Adjustments
Dosage modifications might be required for renal impairment, certain malabsorption syndromes, or concomitant medications that affect calcium metabolism.
Side Effects
Common Side Effects:
Constipation, upset stomach, gas, belching
Rare but Serious Side Effects:
Hypercalcemia (high blood calcium), nausea/vomiting, loss of appetite, weight loss, mental/mood changes, bone/muscle pain, headache, increased thirst/urination, weakness, fatigue, allergic reactions (rash, itching, hives, swelling)
Long-Term Effects:
Kidney stones (with excessive intake), milk-alkali syndrome (with very high, chronic dosing)
Adverse Drug Reactions (ADR):
Severe hypercalcemia requiring medical intervention, allergic reactions.
Contraindications
- Hypercalcemia
- Hypercalciuria
- Severe renal impairment
- Kidney stones (history)
- Hypersensitivity to calcium citrate or any components
- Ventricular fibrillation
- Hypophosphatemia
Drug Interactions
Calcium citrate can decrease the absorption of several medications, including:
- Bisphosphonates (e.g., alendronate)
- Tetracycline antibiotics (e.g., doxycycline, minocycline)
- Quinolone antibiotics (e.g., ciprofloxacin, levofloxacin)
- Levothyroxine
- Digoxin
- Eltrombopag
Concurrent use with thiazide diuretics can increase the risk of hypercalcemia. Calcium citrate may also interact with certain phosphate binders and cellulose sodium phosphate. Consult a drug interaction checker for detailed information. Separate doses of interacting medications as far as possible from calcium citrate administration.
Pregnancy and Breastfeeding
Pregnancy Safety Category: Generally considered safe during pregnancy when used as directed; however, excessive intake should be avoided.
Calcium citrate appears in breast milk and is considered safe during breastfeeding.
Drug Profile Summary
- Mechanism of Action: Provides supplemental calcium for various physiological processes.
- Side Effects: Constipation, upset stomach, hypercalcemia (rarely).
- Contraindications: Hypercalcemia, severe renal impairment, kidney stones.
- Drug Interactions: Several drug interactions, including antibiotics, levothyroxine, and digoxin.
- Pregnancy & Breastfeeding: Generally safe when used as directed.
- Dosage: Varies based on age, condition, and individual needs (see Dosage section).
- Monitoring Parameters: Serum calcium levels, especially in patients with renal impairment.
Popular Combinations
Calcium citrate is often combined with vitamin D to enhance calcium absorption.
Precautions
- Pre-existing conditions: Assess renal function and history of kidney stones.
- Pregnant women: Monitor calcium levels to avoid excessive intake.
- Breastfeeding mothers: Generally safe but monitor infant for constipation.
- Children & elderly: Follow age-specific dosage recommendations.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Calcium citrate?
A: It depends on the individual’s age, condition, and specific needs. Refer to the Dosage section for details.
Q2: What are the common side effects of Calcium citrate?
A: Common side effects include constipation, gas, and stomach upset.
Q3: Can I take Calcium citrate with other medications?
A: Calcium citrate can interact with several medications. Consult a healthcare professional or pharmacist before taking it with other drugs.
Q4: Is Calcium citrate safe during pregnancy and breastfeeding?
A: It’s generally considered safe when taken as directed, but excessive intake should be avoided.
Q5: How should I take Calcium citrate?
A: Take it orally with or without food. Taking smaller doses more frequently may improve absorption and reduce gastrointestinal side effects. Do not exceed 500-600 mg of elemental calcium at one time.
Q6: What should I do if I experience side effects?
A: For mild side effects, try taking calcium citrate with food. If side effects persist or are severe, consult your doctor.
Q7: Can calcium citrate cause kidney stones?
A: Excessive intake of calcium citrate may increase the risk of kidney stones in susceptible individuals. Maintain adequate hydration and adhere to the prescribed dosage.
Q8: What is the difference between calcium citrate and calcium carbonate?
A: Calcium citrate is generally better absorbed, particularly by individuals with low stomach acid, and is less likely to cause constipation than calcium carbonate. Calcium citrate contains less elemental calcium per gram than calcium carbonate.
Q9: Are there any dietary sources of calcium?
A: Yes, calcium-rich foods include dairy products, leafy green vegetables, almonds, and fortified foods.
Q10: How is calcium citrate different from intravenous calcium?
A: Calcium citrate is an oral supplement used for chronic calcium deficiency, while intravenous calcium (e.g., calcium gluconate or calcium chloride) is utilized for acute hypocalcemia requiring immediate correction.
This information is current as of February 16, 2025. Medical knowledge constantly evolves, so it’s always recommended to consult with a healthcare professional for the most up-to-date information.
