Oyster Shell /d 500mg Tablets
It is used to help growth and good health.It is used to prevent or treat soft, brittle bones (osteoporosis).It is used to treat or prevent low calcium levels.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Mineral and Vitamin Supplement; Bone Health Agent
Pharmacologic Class
Calcium Supplement; Vitamin D Analog
Pregnancy Category
Category A (at recommended doses), Category C (at doses exceeding RDA)
FDA Approved
Jan 1970
DEA Schedule
Not Controlled
Overview
What is this medicine?
This medication is a combination of calcium and vitamin D. Calcium is a mineral essential for strong bones, healthy teeth, and proper functioning of muscles and nerves. Vitamin D helps your body absorb calcium from food and supplements, and is also important for bone health and immune function. This supplement helps ensure you get enough of these vital nutrients, especially if your diet is lacking or you have specific health needs.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take this medication with food to ensure proper absorption.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of the reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to explore local drug take-back programs.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take this medication with food to ensure proper absorption.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of the reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to explore local drug take-back programs.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take calcium carbonate with food to improve absorption.
- Separate calcium supplements from other medications (e.g., iron, thyroid hormones, certain antibiotics) by at least 2-4 hours to prevent interactions.
- Ensure adequate fluid intake to help prevent kidney stones, especially with higher calcium intake.
- Engage in weight-bearing exercise (e.g., walking, jogging) to support bone health.
- Maintain a balanced diet rich in calcium (dairy, leafy greens) and Vitamin D (fatty fish, fortified foods).
- Moderate sun exposure can help your body produce Vitamin D, but use sun protection to prevent skin damage.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Calcium: 500 mg elemental calcium (from oyster shell) 1-2 times daily. Vitamin D: Varies by product, typically 200-800 IU daily, often combined with calcium.
Dose Range:
500 - 1200 mg
Condition-Specific Dosing:
Osteoporosis prevention:
1000-1200 mg elemental calcium daily, 600-800 IU Vitamin D daily.
Dietary insufficiency:
As needed to meet recommended daily allowance.
Pediatric Dosing
Neonatal:
Not established (specific pediatric formulations/doses are used if needed)
Infant:
Not established (specific pediatric formulations/doses are used if needed)
Child:
Dosing varies by age and weight, typically based on RDA for calcium (e.g., 700-1000 mg/day) and Vitamin D (600 IU/day). Consult pediatrician.
Adolescent:
1300 mg elemental calcium daily, 600 IU Vitamin D daily (RDA).
Dose Adjustments
Renal Impairment:
Mild:
Use with caution; monitor serum calcium and phosphorus. Adjustment may be needed.
Moderate:
Use with caution; monitor serum calcium, phosphorus, and PTH closely. Doses may need adjustment or active vitamin D forms may be preferred. Avoid if hypercalcemia.
Severe:
Contraindicated or used with extreme caution and close monitoring due to risk of hypercalcemia and hyperphosphatemia. Active vitamin D forms (e.g., calcitriol) are typically used under specialist supervision.
Dialysis:
Contraindicated or used with extreme caution and close monitoring. Active vitamin D forms are typically used. Avoid calcium carbonate if hyperphosphatemia is present.
Hepatic Impairment:
Mild:
No specific dose adjustment typically required.
Moderate:
No specific dose adjustment typically required, but monitor Vitamin D levels as 25-hydroxylation may be impaired in severe liver disease.
Severe:
Monitor Vitamin D levels; 25-hydroxylation may be impaired. Consider 25-hydroxyvitamin D (calcifediol) if severe impairment.
Pharmacology
Mechanism of Action
Calcium is an essential mineral for bone formation, nerve impulse transmission, muscle contraction, and blood coagulation. Vitamin D (cholecalciferol) is a fat-soluble vitamin that, after hydroxylation in the liver (to 25-hydroxyvitamin D) and kidneys (to 1,25-dihydroxyvitamin D, calcitriol), acts as a hormone. Calcitriol promotes intestinal absorption of calcium and phosphorus, regulates bone mineralization, and influences parathyroid hormone (PTH) secretion.
Pharmacokinetics
Absorption:
Bioavailability:
Calcium carbonate: Approximately 20-25% (requires stomach acid for optimal absorption). Vitamin D: Readily absorbed from the small intestine (fat-soluble).
Tmax:
Calcium: Variable, typically 1-4 hours post-ingestion. Vitamin D (cholecalciferol): 4-5 hours.
FoodEffect:
Calcium carbonate absorption is enhanced when taken with food due to increased stomach acid production. Vitamin D absorption is enhanced by dietary fat.
Distribution:
Vd:
Calcium: Not typically reported as Vd; primarily stored in bone (99%). Vitamin D: Extensively distributed to adipose tissue, liver, and muscle.
ProteinBinding:
Calcium: Approximately 40-50% bound to plasma proteins (albumin). Vitamin D: Primarily bound to vitamin D-binding protein (DBP) and albumin.
CnssPenetration:
Limited for calcium; Vitamin D metabolites can cross the blood-brain barrier.
Elimination:
HalfLife:
Calcium: Not applicable (homeostatically regulated). Vitamin D (cholecalciferol): Approximately 24 hours. 25-hydroxyvitamin D: 2-3 weeks. 1,25-dihydroxyvitamin D: 4-6 hours.
Clearance:
Not typically reported for calcium. Vitamin D: Hepatic and renal clearance of metabolites.
ExcretionRoute:
Calcium: Primarily fecal (unabsorbed), renal (filtered and reabsorbed). Vitamin D: Primarily fecal (bile), minor renal excretion of metabolites.
Unchanged:
Not applicable for calcium. Vitamin D: Very little unchanged drug excreted.
Pharmacodynamics
OnsetOfAction:
Not acutely measurable for bone health benefits; long-term effects. Calcium absorption begins within minutes.
PeakEffect:
Not acutely measurable for bone health benefits; long-term effects.
DurationOfAction:
Not acutely measurable for bone health benefits; long-term effects. Calcium levels are homeostatically regulated.
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high calcium levels, including:
+ Weakness
+ Confusion
+ Feeling tired
+ Headache
+ Upset stomach and vomiting
+ Constipation
+ Bone pain
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only have mild ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or do not go away, contact your doctor:
Upset stomach or vomiting
Constipation
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high calcium levels, including:
+ Weakness
+ Confusion
+ Feeling tired
+ Headache
+ Upset stomach and vomiting
+ Constipation
+ Bone pain
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only have mild ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or do not go away, contact your doctor:
Upset stomach or vomiting
Constipation
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Symptoms of too much calcium (hypercalcemia): Nausea, vomiting, constipation, loss of appetite, increased thirst, increased urination, muscle weakness, fatigue, confusion, bone pain, kidney stones.
- Symptoms of too much Vitamin D (Vitamin D toxicity): Similar to hypercalcemia, plus weight loss, irregular heartbeat, and kidney damage.
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
Certain health conditions, including:
+ High calcium levels
+ High vitamin D levels
+ Kidney stones
+ Low phosphate levels
This list is not exhaustive, and it is crucial to discuss all your health problems with your doctor.
Additionally, provide your doctor and pharmacist with a comprehensive list of all the medications you are taking, including:
Prescription medications
Over-the-counter (OTC) medications
Natural products
Vitamins
It is vital to verify that it is safe to take this medication with all your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
Certain health conditions, including:
+ High calcium levels
+ High vitamin D levels
+ Kidney stones
+ Low phosphate levels
This list is not exhaustive, and it is crucial to discuss all your health problems with your doctor.
Additionally, provide your doctor and pharmacist with a comprehensive list of all the medications you are taking, including:
Prescription medications
Over-the-counter (OTC) medications
Natural products
Vitamins
It is vital to verify that it is safe to take this medication with all your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you have a known allergy to tartrazine (FD&C Yellow No. 5), consult with your doctor before proceeding, as some formulations of this drug may contain tartrazine.
When taking this medication, be aware that it may interfere with the absorption of other oral medications. To minimize potential interactions, discuss with your doctor the best schedule for taking your other medications, which may need to be administered at a different time than this drug.
Adhere strictly to the dietary plan recommended by your doctor to ensure safe and effective use of this medication. Additionally, if you are pregnant, planning to become pregnant, or are breastfeeding, it is crucial to discuss the potential benefits and risks of this medication with your doctor, as this will help determine the best course of action for both you and your baby.
When taking this medication, be aware that it may interfere with the absorption of other oral medications. To minimize potential interactions, discuss with your doctor the best schedule for taking your other medications, which may need to be administered at a different time than this drug.
Adhere strictly to the dietary plan recommended by your doctor to ensure safe and effective use of this medication. Additionally, if you are pregnant, planning to become pregnant, or are breastfeeding, it is crucial to discuss the potential benefits and risks of this medication with your doctor, as this will help determine the best course of action for both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe nausea and vomiting
- Profound constipation
- Extreme thirst and frequent urination
- Muscle weakness and fatigue
- Confusion or altered mental status
- Kidney stones or kidney damage
- Cardiac arrhythmias (rare but serious)
What to Do:
If you suspect an overdose, seek immediate medical attention. Call your local poison control center (e.g., 1-800-222-1222 in the US) or emergency services (911). Treatment may involve stopping the supplement, hydration, and medications to lower calcium levels.
Drug Interactions
Major Interactions
- Digitalis glycosides (e.g., Digoxin) + high dose calcium/Vitamin D (increased risk of arrhythmias due to hypercalcemia)
- Thiazide diuretics + high dose calcium/Vitamin D (increased risk of hypercalcemia)
Moderate Interactions
- Tetracycline antibiotics (e.g., Doxycycline, Minocycline): Calcium can chelate, reducing absorption. Separate by 2-4 hours.
- Fluoroquinolone antibiotics (e.g., Ciprofloxacin, Levofloxacin): Calcium can chelate, reducing absorption. Separate by 2-6 hours.
- Levothyroxine: Calcium can impair absorption. Separate by at least 4 hours.
- Bisphosphonates (e.g., Alendronate, Risedronate): Calcium can impair absorption. Separate by at least 30-60 minutes.
- Iron supplements: Calcium can reduce iron absorption. Separate by at least 2 hours.
- Phenytoin, Carbamazepine, Barbiturates (e.g., Phenobarbital): May increase Vitamin D metabolism, potentially leading to Vitamin D deficiency.
- Corticosteroids (e.g., Prednisone): May reduce calcium absorption and increase calcium excretion, potentially leading to Vitamin D deficiency.
- Bile acid sequestrants (e.g., Cholestyramine, Colestipol): May reduce absorption of fat-soluble Vitamin D.
- Orlistat: May reduce absorption of fat-soluble Vitamin D.
- Loop diuretics (e.g., Furosemide): May increase urinary calcium excretion, potentially leading to hypocalcemia with long-term use.
Minor Interactions
- Oxalic acid (in spinach, rhubarb), Phytic acid (in whole grains, legumes): Can reduce calcium absorption. Consume calcium-rich foods/supplements separately.
- Caffeine, Alcohol: May slightly increase calcium excretion.
Monitoring
Baseline Monitoring
Serum Calcium (total and ionized)
Rationale: To establish baseline levels and identify pre-existing hyper/hypocalcemia.
Timing: Prior to initiation, especially with higher doses or risk factors.
Serum 25-hydroxyvitamin D (25-OH D)
Rationale: To assess baseline Vitamin D status and guide dosing.
Timing: Prior to initiation, especially if deficiency is suspected.
Renal Function (Creatinine, eGFR)
Rationale: To assess kidney function, as renal impairment affects calcium and Vitamin D metabolism and excretion.
Timing: Prior to initiation, especially in elderly or those with kidney disease risk.
Routine Monitoring
Serum Calcium (total and ionized)
Frequency: Every 3-6 months initially, then annually or as clinically indicated.
Target: Total: 8.5-10.2 mg/dL; Ionized: 4.5-5.6 mg/dL
Action Threshold: If consistently >10.5 mg/dL (total) or >5.8 mg/dL (ionized), consider dose reduction or discontinuation, investigate cause.
Serum 25-hydroxyvitamin D (25-OH D)
Frequency: Every 6-12 months, or as needed to achieve target levels.
Target: >30 ng/mL (optimal 40-60 ng/mL)
Action Threshold: If <30 ng/mL, consider dose increase. If >100 ng/mL, consider dose reduction/discontinuation due to potential toxicity.
Renal Function (Creatinine, eGFR)
Frequency: Annually or as clinically indicated, especially in patients with risk factors for kidney disease.
Target: Normal eGFR >60 mL/min/1.73m²
Action Threshold: Significant decline in eGFR warrants re-evaluation of calcium/Vitamin D supplementation.
24-hour Urine Calcium
Frequency: If hypercalcemia or hypercalciuria is suspected, or with high doses.
Target: <250 mg/24 hours (women), <300 mg/24 hours (men)
Action Threshold: If >250-300 mg/24 hours, investigate cause, consider dose reduction, or alternative calcium source.
Symptom Monitoring
- Symptoms of hypercalcemia: Nausea, vomiting, constipation, polyuria, polydipsia, muscle weakness, fatigue, confusion, kidney stones.
- Symptoms of Vitamin D toxicity: Anorexia, weight loss, polyuria, constipation, cardiac arrhythmias, kidney damage.
Special Patient Groups
Pregnancy
Calcium and Vitamin D are essential nutrients during pregnancy for fetal bone development and maternal health. Recommended daily allowances should be met through diet and supplementation if necessary. Excessive doses should be avoided.
Trimester-Specific Risks:
First Trimester:
Essential for early fetal development; generally safe at recommended doses.
Second Trimester:
Continued importance for fetal skeletal growth; generally safe at recommended doses.
Third Trimester:
High demand for calcium for rapid fetal bone mineralization; generally safe at recommended doses. Avoid excessive doses.
Lactation
Calcium and Vitamin D are excreted into breast milk. Supplementation at recommended doses is generally considered safe and beneficial for both mother and infant. Excessive doses should be avoided.
Infant Risk:
Low risk at recommended maternal doses. High maternal doses could potentially lead to hypercalcemia in the infant, though rare.
Pediatric Use
Dosing must be carefully adjusted based on age, weight, and specific dietary needs or deficiencies. Excessive intake can lead to hypercalcemia and Vitamin D toxicity. Always consult a pediatrician for appropriate dosing.
Geriatric Use
Elderly individuals often have increased needs for calcium and Vitamin D due to decreased dietary intake, reduced skin synthesis of Vitamin D, and impaired renal 1-alpha-hydroxylation. They are at higher risk for osteoporosis and fractures, making supplementation common. However, monitor for hypercalcemia, especially if renal function is impaired.
Clinical Information
Clinical Pearls
- Calcium carbonate (from oyster shell) should be taken with food to maximize absorption, as it requires stomach acid.
- Separate calcium supplements from iron, thyroid hormones, and certain antibiotics (tetracyclines, fluoroquinolones) by several hours to avoid absorption interference.
- For individuals with low stomach acid (e.g., on PPIs or H2 blockers), calcium citrate may be a better absorbed alternative to calcium carbonate.
- Regular monitoring of serum calcium and 25-hydroxyvitamin D levels is important, especially with higher doses or in patients with renal impairment.
- Encourage lifestyle measures such as weight-bearing exercise and a balanced diet alongside supplementation for optimal bone health.
Alternative Therapies
- Dietary calcium (dairy products, fortified foods, leafy greens)
- Dietary Vitamin D (fatty fish, fortified foods, sun exposure)
- Prescription Vitamin D (e.g., ergocalciferol, cholecalciferol at higher doses)
- Bisphosphonates (for osteoporosis treatment)
- Selective Estrogen Receptor Modulators (SERMs) (for osteoporosis treatment)
- Parathyroid hormone analogs (for severe osteoporosis)
Cost & Coverage
Average Cost:
$5 - $30 per 30-100 tablets
Generic Available:
Yes
Insurance Coverage:
Often OTC; may be covered by FSA/HSA. Prescription forms may be covered by some insurance plans.
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist. If you have any questions or concerns about this medication, don't hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide detailed information about the overdose, including the medication taken, the amount, and the time it occurred.