Zemplar 4mcg Capsules
It is used to treat or prevent high parathyroid hormone levels in certain patients.
Drug Class
Agent for secondary hyperparathyroidism
Pharmacologic Class
Selective vitamin D receptor activator (VDRA)
Pregnancy Category
Category C
FDA Approved
Apr 2005
DEA Schedule
Not Controlled
Overview
What is this medicine?
Paricalcitol is a type of vitamin D that helps control a hormone called parathyroid hormone (PTH) in people with kidney disease. When kidneys don't work well, PTH levels can get too high, which can cause bone problems. This medicine helps lower PTH levels to keep your bones healthy.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. It's essential to continue taking this medication as directed by your doctor or healthcare provider, even if you're feeling well.
Storing and Disposing of Your Medication
Store this 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 medications, do not flush them down the toilet or pour them 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. Avoid taking two doses at the same time or taking extra doses. If you take this medication three times a week and miss a dose, contact your doctor for guidance on what to do next.
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. It's essential to continue taking this medication as directed by your doctor or healthcare provider, even if you're feeling well.
Storing and Disposing of Your Medication
Store this 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 medications, do not flush them down the toilet or pour them 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. Avoid taking two doses at the same time or taking extra doses. If you take this medication three times a week and miss a dose, contact your doctor for guidance on what to do next.
Lifestyle & Tips
- Take exactly as prescribed by your doctor.
- Do not take extra calcium or vitamin D supplements unless specifically instructed by your doctor.
- Follow any dietary restrictions, especially regarding calcium and phosphorus intake, as advised by your doctor or dietitian.
- Attend all scheduled blood tests to monitor calcium, phosphorus, and PTH levels.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial dose individualized based on baseline PTH levels. For CKD Stages 3/4: 1 mcg daily or 2 mcg three times weekly. For CKD Stage 5 (dialysis): Initial dose (mcg) = Baseline PTH (pg/mL) / 80, administered three times weekly, no more frequently than every other day.
Dose Range:
1 - 16 mg
Condition-Specific Dosing:
CKD Stages 3/4:
Initial: 1 mcg daily or 2 mcg three times weekly. Adjust by 1 mcg increments every 2-4 weeks to maintain PTH within target range (35-70 pg/mL for Stage 3/4). Max 4 mcg daily.
CKD Stage 5 (Dialysis):
Initial: Calculated based on baseline PTH. Adjust by 2-4 mcg increments every 2-4 weeks to maintain PTH within target range (150-300 pg/mL). Max 16 mcg three times weekly.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment needed for CKD Stages 3/4, follow standard dosing guidelines for these stages.
Moderate:
No specific adjustment needed for CKD Stages 3/4, follow standard dosing guidelines for these stages.
Severe:
No specific adjustment needed for CKD Stage 5 (dialysis), follow standard dosing guidelines for this stage.
Dialysis:
Follow standard dosing guidelines for CKD Stage 5 (dialysis patients). Paricalcitol is not significantly removed by hemodialysis.
Hepatic Impairment:
Mild:
No dose adjustment necessary.
Moderate:
No dose adjustment necessary.
Severe:
No dose adjustment necessary, but monitor serum calcium and phosphorus more frequently.
Pharmacology
Mechanism of Action
Paricalcitol is a synthetic analog of calcitriol, the active form of vitamin D. It selectively activates the vitamin D receptor (VDR) in target tissues, including the parathyroid glands. By activating VDRs in the parathyroid glands, paricalcitol directly suppresses parathyroid hormone (PTH) synthesis and secretion without significantly increasing intestinal absorption of calcium and phosphorus, thus minimizing the risk of hypercalcemia and hyperphosphatemia compared to non-selective vitamin D analogs.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 100% (oral solution), 80-90% (capsules)
Tmax:
2-4 hours
FoodEffect:
Food does not significantly affect the absorption of paricalcitol capsules.
Distribution:
Vd:
Approximately 3.1 L/kg
ProteinBinding:
>99%
CnssPenetration:
Limited
Elimination:
HalfLife:
Approximately 4-7 hours (terminal half-life)
Clearance:
Not available (primarily hepatic metabolism and biliary excretion)
ExcretionRoute:
Biliary/fecal (approximately 70%), urinary (approximately 30%)
Unchanged:
Less than 2% (urinary), less than 10% (fecal)
Pharmacodynamics
OnsetOfAction:
Within days to weeks (PTH suppression)
PeakEffect:
Within 2-4 weeks (PTH suppression)
DurationOfAction:
Dependent on dose and individual response, effects on PTH can last for several days after a single dose.
Safety & Warnings
Side Effects
Serious Side Effects: Seek Medical Attention Immediately
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 medical help right away:
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
+ Fatigue
+ Headache
+ Nausea and vomiting
+ Constipation
+ Bone pain
Signs of high or low blood pressure, such as:
+ Severe headache
+ Dizziness
+ Fainting
+ Changes in vision
Abnormal heartbeat
Seizures
Frequent urination
Weight loss
Decreased appetite
Excessive thirst
Swelling
Vomiting blood or coffee ground-like material
Black, tarry, or bloody stools
Fever or chills
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or persist, contact your doctor or seek medical help:
Diarrhea
Nausea or vomiting
Dizziness or headache
Nasal or throat irritation
Sleep disturbances
Joint pain
Eye redness
This is not an exhaustive list of possible 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 medical help right away:
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
+ Fatigue
+ Headache
+ Nausea and vomiting
+ Constipation
+ Bone pain
Signs of high or low blood pressure, such as:
+ Severe headache
+ Dizziness
+ Fainting
+ Changes in vision
Abnormal heartbeat
Seizures
Frequent urination
Weight loss
Decreased appetite
Excessive thirst
Swelling
Vomiting blood or coffee ground-like material
Black, tarry, or bloody stools
Fever or chills
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or persist, contact your doctor or seek medical help:
Diarrhea
Nausea or vomiting
Dizziness or headache
Nasal or throat irritation
Sleep disturbances
Joint pain
Eye redness
This is not an exhaustive list of possible 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:
- Signs of high calcium (hypercalcemia): feeling sick to your stomach, vomiting, constipation, loss of appetite, feeling tired or weak, confusion, increased thirst or urination.
- Signs of high phosphorus (hyperphosphatemia): itching, bone pain, red eyes.
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. Be sure to describe the allergic reaction and its symptoms.
Certain health conditions, such as high calcium levels or high vitamin D levels.
* If you are breastfeeding, as you should not breastfeed while taking this medication.
This list is not exhaustive, and it is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health problems with your doctor and pharmacist. They will help you determine if it is safe to take this medication with your other medications and health conditions.
Remember, do not 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. Be sure to describe the allergic reaction and its symptoms.
Certain health conditions, such as high calcium levels or high vitamin D levels.
* If you are breastfeeding, as you should not breastfeed while taking this medication.
This list is not exhaustive, and it is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health problems with your doctor and pharmacist. They will help you determine if it is safe to take this medication with your other medications and health conditions.
Remember, do not 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. Regular blood tests will be necessary, as directed by your doctor, to monitor your condition. Be sure to discuss any concerns or questions with your doctor.
If you are currently taking other supplements that contain vitamin D, consult with your doctor to avoid excessive intake. Additionally, if you are using antacids or other products that contain aluminum, inform your doctor, as this may interact with your medication.
Consuming grapefruit juice or eating grapefruit regularly may also interact with this medication, so it is crucial to discuss this with your doctor. To maximize the effectiveness of your treatment, adhere to the diet plan recommended by your doctor.
If you are pregnant or planning to become pregnant, notify your doctor immediately. You will need to have a discussion about the potential benefits and risks of using this medication during pregnancy.
When taking this medication, be mindful of potential interactions with other substances. If you are also taking cholestyramine or mineral oil, take this medication at least 1 hour before or 4 to 6 hours after taking cholestyramine or mineral oil to minimize interactions.
If you are currently taking other supplements that contain vitamin D, consult with your doctor to avoid excessive intake. Additionally, if you are using antacids or other products that contain aluminum, inform your doctor, as this may interact with your medication.
Consuming grapefruit juice or eating grapefruit regularly may also interact with this medication, so it is crucial to discuss this with your doctor. To maximize the effectiveness of your treatment, adhere to the diet plan recommended by your doctor.
If you are pregnant or planning to become pregnant, notify your doctor immediately. You will need to have a discussion about the potential benefits and risks of using this medication during pregnancy.
When taking this medication, be mindful of potential interactions with other substances. If you are also taking cholestyramine or mineral oil, take this medication at least 1 hour before or 4 to 6 hours after taking cholestyramine or mineral oil to minimize interactions.
Overdose Information
Overdose Symptoms:
- Hypercalcemia (severe nausea, vomiting, constipation, anorexia, weakness, fatigue, confusion, polyuria, polydipsia, dehydration, stupor, coma)
- Hyperphosphatemia
- Hypermagnesemia (if magnesium-containing antacids are co-administered)
What to Do:
Discontinue paricalcitol immediately. Initiate measures to lower serum calcium (e.g., low-calcium diet, hydration, loop diuretics, corticosteroids, calcitonin, bisphosphonates). Monitor serum calcium, phosphorus, and PTH levels. Dialysis may be considered in severe cases. Call 1-800-222-1222 (Poison Control) or seek immediate medical attention.
Drug Interactions
Major Interactions
- Ketoconazole (and other strong CYP3A4 inhibitors)
- Digitalis glycosides (e.g., Digoxin)
Moderate Interactions
- Phosphate binders (calcium-containing)
- Magnesium-containing antacids
- Thiazide diuretics
Monitoring
Baseline Monitoring
Serum Calcium (ionized or total)
Rationale: To establish baseline and identify pre-existing hypercalcemia, which is a contraindication.
Timing: Prior to initiation of therapy
Serum Phosphorus
Rationale: To establish baseline and identify pre-existing hyperphosphatemia.
Timing: Prior to initiation of therapy
Intact Parathyroid Hormone (iPTH)
Rationale: To establish baseline and guide initial dosing.
Timing: Prior to initiation of therapy
Serum Creatinine/eGFR
Rationale: To assess kidney function and determine appropriate dosing strategy (CKD stage).
Timing: Prior to initiation of therapy
Alkaline Phosphatase
Rationale: To assess bone turnover.
Timing: Prior to initiation of therapy
Routine Monitoring
Serum Calcium (ionized or total)
Frequency: At least twice weekly during dose initiation/adjustment, then monthly once stable.
Target: Within normal limits (e.g., 8.4-10.2 mg/dL total calcium)
Action Threshold: If corrected serum calcium > 10.5 mg/dL, reduce or interrupt paricalcitol dose.
Serum Phosphorus
Frequency: At least twice weekly during dose initiation/adjustment, then monthly once stable.
Target: Within normal limits (e.g., 2.5-4.5 mg/dL)
Action Threshold: If serum phosphorus > 5.5 mg/dL, reduce or interrupt paricalcitol dose and/or adjust phosphate binder therapy.
Intact Parathyroid Hormone (iPTH)
Frequency: Every 2-4 weeks during dose initiation/adjustment, then every 1-3 months once stable.
Target: CKD Stage 3/4: 35-70 pg/mL; CKD Stage 5: 150-300 pg/mL
Action Threshold: Adjust dose to maintain PTH within target range. If PTH decreases too rapidly or falls below target, reduce or interrupt dose.
Calcium x Phosphorus Product
Frequency: At least twice weekly during dose initiation/adjustment, then monthly once stable.
Target: < 55 mg²/dL²
Action Threshold: If product > 55 mg²/dL², reduce or interrupt paricalcitol dose and/or adjust phosphate binder therapy.
Symptom Monitoring
- Symptoms of hypercalcemia (e.g., nausea, vomiting, constipation, anorexia, weakness, fatigue, confusion, polyuria, polydipsia)
- Symptoms of hyperphosphatemia (e.g., pruritus, bone pain, vascular calcification symptoms)
Special Patient Groups
Pregnancy
Category C. There are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus. Animal studies have shown adverse effects on fetal development at doses higher than human therapeutic doses.
Trimester-Specific Risks:
First Trimester:
Potential for fetal harm based on animal data, but human data is lacking.
Second Trimester:
Potential for fetal harm based on animal data, but human data is lacking.
Third Trimester:
Potential for fetal harm based on animal data, but human data is lacking.
Lactation
L3 (Moderately Safe). It is not known whether paricalcitol is excreted in human milk. Caution should be exercised when paricalcitol is administered to a nursing woman. The decision to discontinue nursing or discontinue the drug should take into account the importance of the drug to the mother.
Infant Risk:
Potential for hypercalcemia in the infant. Monitor infant for signs of hypercalcemia (e.g., poor feeding, vomiting, constipation, lethargy).
Pediatric Use
Safety and efficacy have not been established in pediatric patients. Use is not recommended.
Geriatric Use
No overall differences in safety or effectiveness were observed between elderly and younger patients. Dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
Clinical Information
Clinical Pearls
- Paricalcitol is a selective VDR activator, meaning it aims to suppress PTH with less impact on calcium and phosphorus levels compared to older vitamin D analogs like calcitriol.
- Strict adherence to monitoring of serum calcium, phosphorus, and PTH is crucial to prevent hypercalcemia and hyperphosphatemia.
- Patients should be educated on the symptoms of hypercalcemia and instructed to report them immediately.
- Avoid concomitant use of calcium-containing phosphate binders and magnesium-containing antacids unless closely monitored.
- Dosing is highly individualized and requires frequent adjustments based on laboratory values.
Alternative Therapies
- Calcitriol (Rocaltrol, Calcijex)
- Doxercalciferol (Hectorol)
- Cinacalcet (Sensipar) - a calcimimetic, not a vitamin D analog, but also used for secondary hyperparathyroidism.
- Etelcalcetide (Parsabiv) - another calcimimetic.
Cost & Coverage
Average Cost:
Varies widely, typically several hundred to over a thousand USD per 30 capsules
Generic Available:
Yes
Insurance Coverage:
Tier 2 or 3 (Brand), Tier 1 (Generic)
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 for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.