Calcium

Calcium is a natural essential mineral belonging to the supplement category electrolyte class.

Calcium is also known as lime.

Calcium is an essential macromineral responsible for numerous structural components such as bones and teeth and physiological mechanisms in the body.

Dairy products, fortified soy products, fish with bones (especially salmon and sardines), tofu, broccoli, collard greens, and mustard are good dietary calcium sources.

Calcium is mainly absorbed in the small intestine with the help of vitamin D and then distributed in the bloodstream, regulated by hormones, and eliminated mainly through the kidneys via urine.

The common side effects of calcium include gastrointestinal effects like constipation, dyspepsia and nausea.

Calcium is available in the form of oral solid dosage forms.

Biochemical action of calcium

Calcium belonging to the supplement class acts as a signalling agent and helps regulate muscle contraction, neurotransmitter release, hormone secretion, and gene expression. Calcium acts via calcium homeostasis.

The two primary processes through which calcium is absorbed in the small intestine are paracellular passive transport across the whole small intestine and transcellular active transportation in the duodenum and jejunum. Signalling molecules such as parathyroid hormone (PTH), vitamin D, and calcitonin regulate calcium levels. Numerous physiological processes depend significantly on calcium. Several calcium channels are in blood artery constriction and relaxation, muscular contraction, neuronal action potentials, and cardiac electrophysiology. Calcium is an essential element of bone and teeth. Additionally, calcium ions are essential for blood clotting pathways. Overall, calcium is important for maintaining various cellular and physiological processes in the body as well as maintaining the structural integrity of bones and teeth.

Calcium is available in various forms like caplets, capsules, tablets and chewable tablets.

• Caplets, capsules and tablets are to be swallowed whole with water/liquid, as applicable.
• Chewable tablets are to be chewed completely before swallowing, as applicable.

Calcium can be used as a supplement support for bone mineralization.

Calcium supplement is used for the development and maintenance of strong bones and teeth.

As a supplement, calcium helps in maintaining proper nerve function and regulating heart muscle contractions, ensuring a steady heartbeat.

Adequate intake of calcium supplements is useful for overall health, and shortages can cause osteoporosis, muscle cramping, and problems with blood clotting.

Vitamins and natural supplements should not replace a balanced diet.

This product is not intended to diagnose, treat or prevent any disease(s).

Calcium may be useful as a supplement for the following health benefits:

• Calcium deficiency: Calcium supplementation is used in high-risk patients, such as pregnant and lactating mothers, to treat or prevent deficits. Acute severe hypocalcemia is treated with intravenous calcium, whereas chronic cases are treated with oral calcium and vitamin D supplements to improve absorption.
• Rickets and osteomalacia: Bone problems can be caused by a calcium or vitamin D shortage.
• Postmenopausal women: Menopause causes a decrease in estrogen, which causes calcium loss from bones and an increased risk of osteoporosis and fractures in postmenopausal women. Hence calcium supplements are recommended.
• Bone mineral density (BMD), osteoporosis prophylaxis and reducing fracture risk: Calcium supplements are commonly used in vulnerable populations to enhance bone health, prevent osteoporosis, and reduce fractures. Vitamin D, trace minerals, weight-bearing exercise, and anti-resorptive medications may also be advised.
• Cancer: The effect of calcium on cancer risk, especially in the colon and rectum, remains unknown. High intakes may reduce risk, although the evidence is inconsistent and varies with cancer type. Further investigation is required.
• Pre-eclampsia: Preeclampsia is a lethal condition of late pregnancy which include symptoms like excessive blood pressure and excessive quantities of protein in the urine. Calcium supplements can lower the risk of preeclampsia in some pregnant women who consume insufficient calcium.
• Hypertension: Intracellular calcium is essential for cardiovascular function regulation. Calcium influx increases tone in vascular smooth muscle cells, resulting in increased vascular resistance and blood pressure.

Calcium supplementation may be administered orally.

Calcium supplements are available in the form of tablets and capsules, which can be taken orally. Some formulations may need to be taken with food, while others can be taken without regard to meals. Chewable tablets should be chewed thoroughly before swallowing. These formulations are often more palatable and can be taken without water.

The dosage and duration of treatment should be as per the clinical judgment of the treating healthcare professional).

Vitamins and natural supplements should not replace a balanced diet

This product is not intended to diagnose, treat or prevent any disease(s).

• Caplet: 315mg/250IU, 500mg/200IU, 500mg/600IU
• Capsule: 600mg/100IU, 600mg/400IU, 600mg/500IU, 600mg/1000IU
• Tablet: 250mg/125IU, 200mg/250IU, 250mg/200IU, 315mg/215IU, 500mg/200IU, 600mg/200IU, 600mg/400IU, 600mg/800IU
• Tablet, chewable: 250mg/400IU, 500mg/100IU, 500mg/200IU, 500mg/600IU, 600mg/400IU, 600mg/800IU

Calcium is available in the form of caplets, capsules, tablets and chewable tablets.

Calcium should be used as supplement support for maintaining strong bones along with appropriate dietary restrictions.

• Limit the consumption of drinks that include caffeine, such as coffee, tea, chocolate, and alcoholic beverages, as this substance could hinder calcium absorption.
• Avoid consuming high-fibre and oxalate foods like legumes, potatoes or almonds as they may interfere with calcium absorption.
• Stay within your daily calorie needs.

The dietary restriction should be individualized as per patient requirements.

Recommended Daily Allowance (RDA)

The adult RDA set is 1000 mg/day and 1200 mg/day for men and women, respectively.

Upper Tolerable Intake (UTL):

No UTL is set for calcium, as data concerning adverse effects are not sufficient.

• Calcium supplementation may be contraindicated under the following conditions:-
• Patients with chronic renal disease and a history of calcium-containing kidney stones.
• Hyperparathyroidism.
• Sarcoidosis or other granulomatous disorders.
• Hypercalcaemia.
• Hypersensitivity to calcium supplements.
• History of calcium-containing nephrolithiasis should avoid excessive calcium intake.

• The treating healthcare must closely keep a watch and monitor for signs and symptoms such as follows nausea, diarrhoea or loss of appetite.It is recommended to discontinue calcium in case of GI disturbances.
• Calcium should be used cautiously in postmenopausal women as it has been shown to cause a higher risk of kidney stones.
• Calcium supplements should be used with meals with caution for those who have achlorhydria because it reduces calcium absorption.
• Smokers absorb less calcium from the stomach and may need calcium supplements.

Caution is advised when consuming alcohol with calcium.

Safe to use during breastfeeding.

Limit the consumption of foods and beverages that include caffeine, such as coffee, tea, chocolate, and alcoholic beverages, as this substance could hinder the absorption of calcium.

Calcium is generally well-tolerated.

The adverse reactions related to calcium can be categorized as-

• Common: Constipation, upset stomach or gas, nausea or vomiting and loss of appetite
• Less Common: Hypercalcemia and kidney stones.
• Rare: Allergic reactions, bone pain or joint pain and irregular heart rhythms.

The clinically relevant drug interactions of calcium are briefly summarized here:

• Antacids, including H2 antagonists and proton pump inhibitors: Both calcium carbonate and phosphate require acidity for solubilization, and drugs that elevate stomach pH can interfere with calcium absorption. Calcium excretion may be increased by antacids containing aluminium or magnesium.
• Bisphosphonates: Bisphosphonates treat osteoporosis but can cause hypocalcemia, reducing bone mineral density. Adequate consumption of both calcium and vitamin D is essential for those taking bisphosphonates. However, the drug is to be taken 30 minutes before calcium supplementation.
• Caffeine: coffee increases urine calcium excretion and may alter calcium absorption; ensure appropriate calcium intake and watch for signs and symptoms of inadequacy in persons with high caffeine intake.
• Calcium channel blockers: Calcium supplements can antagonistically affect the beneficial action of calcium channel blockers, potentially causing arrhythmias to reoccur; avoid high-dose supplements unless under medical supervision.
• Cardiac glycosides (e.g. digoxin): When used with digoxin, high-dose calcium may increase toxicity; use with caution unless under medical supervision.
• Corticosteroids: Long-term corticosteroid use has been linked to decreased calcium absorption and osteoporosis. Monitor for potential deficient signs and consider calcium supplementation while on therapy.
• Excess dietary fat: This increases urinary excretion of calcium — ensure adequate calcium intake and monitor for signs and symptoms of deficiency.
• Excess fibre, including guar gum: May delay or decrease absorption of calcium—separate doses by at least 2 hours.
• Iron: Concurrent administration of calcium with iron may reduce the absorption of both minerals—separate supplemental or dietary intake of minerals by at least 2 hours.
• Levothyroxine: Calcium administered concurrently may reduce drug absorption, while levothyroxine may block calcium absorption, e.g. calcium carbonate — separate doses by at least 4 hours.
• Lysine: Additive effects may occur as lysine enhances intestinal absorption and reduces renal excretion of calcium — potentially beneficial interaction.
• Magnesium: Magnesium decreases calcium absorption by competing for the same absorption pathway. However, it is unclear if this mineral interaction is clinically significant — it is advisable to separate doses by at least 2 hours.
• Oestrogen and progesterone: Calcium supplementation in combination with these hormones will have an additive effect on minimising bone resorption in postmenopausal women — potentially beneficial interaction, so consider increasing intake.
• Phosphorus: Excess intake (soft drinks, meat consumption) can increase urinary excretion of calcium — ensure adequate calcium intake and monitor for signs and symptoms of deficiency.
• Quinolone antibiotics: Drug bioavailability may be reduced by concurrent administration with calcium supplements, reducing drug efficacy and increasing the risk of developing bacterial resistance — quinolones should be taken either 2 hours before or 4–6 hours after calcium.
• Tetracyclines: Calcium supplements form complexes with these antibiotics and render 50% or more insoluble, reducing the drug's efficacy and calcium absorption—separate doses by at least 2 hours.

The common side of calcium includes the following:

• Constipation
• Upset stomach or gas
• Nausea or vomiting
• Loss of appetite
• Increased thirst and urination
• Headache
• Dizziness
• Kidney stones (with excessive intake)

The use of calcium should be prudent in the following group of special populations

• Pregnancy:

Pregnancy category: A

The use of calcium during pregnancy is generally acceptable, and clinical studies have shown no evidence of fetal risk.

The RDA for calcium in pregnant women between the ages of 14 and 18 is 1300 mg/day, and for the age of 18-50 years is 1000 mg/day. The safety of calcium supplementation during pregnancy doses can go up to 2000 mg/day.

• Paediatrics: Calcium is vital for maintaining bone health in the pediatric population.

Calcium supplements are the best way to help children get enough calcium daily.

The RDA for calcium in paediatrics ranges from 200-1300 mg/day.

Dosage Adjustment for Paediatric Patients

There are no specific dosage adjustments provided.

• Geriatrics: There is a severe calcium deficiency among the elderly population.

The RDA for calcium in geriatrics is 1200 mg/day.

• Lactating mothers: Using calcium during breastfeeding is generally acceptable, and clinical studies have shown no evidence of fetal risk.

The RDA for calcium in lactating mothers ages 14-18 is 1300 mg/day, and the age between 18 and 50 is 1000 mg/day.

Dosage Adjustment in Kidney Impairment

There are no specific dosage adjustments provided.

Dosage Adjustment in Hepatic Impairment

There are no specific dosage adjustments provided.

Dosage Adjustment for Adult Patients

Dietary supplement

1-2 tablets/caplets PO BID with or without food (food may increase absorption).

The physician should be vigilant about the knowledge pertaining to the identification and treatment of overdosage of calcium. Overdosing on calcium supplements can cause hypercalcemia, which can cause symptoms like constipation, nausea, vomiting, and kidney stones.

There is no specific antidote or treatment for excessive intake of supplemental calcium. When an overdose is suspected, calcium should be terminated immediately, increasing fluid intake. Supportive treatment should also be given, along with addressing any symptoms that persist or worsen. Physical therapy might be added if necessary.

Biochemistry profile of calcium

Calcium is an essential mineral for many physiological functions in the human body. Approximately 99% of the body's calcium is stored in the skeleton, so it is crucial for maintaining bone health. The remaining 1% is responsible for vital processes like muscular contraction, neuron signalling, blood coagulation, and enzyme activation.

PTH, calcitonin, and active vitamin D (calcitriol) are a few of the hormones that control calcium homeostasis. The parathyroid glands secrete PTH, which increases calcium release from bones and improves calcium reabsorption in the kidneys, raising blood calcium levels. By increasing calcium deposition in bones and lowering blood calcium levels, the thyroid gland's hormone calcitonin generates a contrary effect.

Kinetic profile:

• Absorption: The proximal part of the small intestine mainly absorbs calcium. Vitamin D is necessary for the active absorption of calcium as it improves the production of calcium-binding proteins and calcium channels in intestinal cells. Variables like pH, dietary calcium intake, and other minerals can also influence calcium absorption.
• Distribution: Once ingested, calcium travels to the bloodstream, either ionized or protein-bound. Ionized calcium is physiologically active and controls various processes in the body.
• Metabolism: Hormones such as parathyroid hormone (PTH), calcitonin, and calcitriol (active vitamin D) strictly regulate calcium metabolism. When blood calcium levels are reduced, PTH is released, encouraging bone calcium release and renal calcium reabsorption. In response to increased blood calcium levels, the hormone calcitonin is released, which promotes calcium deposition in bones and inhibits kidney reabsorption.
• Elimination: The excess calcium is primarily eliminated via the kidneys through urine. Dietary intake, hormonal control, and renal function are some of the variables that influence the rate of calcium excretion.

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2. https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/
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