Zemplar 5mcg/ml Inj 1ml
It is used to treat or prevent high parathyroid hormone levels in certain patients.
Drug Class
Vitamin D Analog
Pharmacologic Class
Selective Vitamin D Receptor Activator (VDRA)
Pregnancy Category
Category C
FDA Approved
Dec 1998
DEA Schedule
Not Controlled
Overview
What is this medicine?
Zemplar is a medicine given by injection to help 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 problems with bones and other parts of the body. Zemplar works like a special type of vitamin D to lower PTH levels and keep your calcium and phosphorus levels balanced.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. It is essential to follow the dosage instructions carefully. This medication is administered as an intravenous injection, which means it is given as a shot into a vein.
Storing and Disposing of Your Medication
If you need to store this medication at home, consult with your doctor, nurse, or pharmacist to determine the best storage method.
Missing a Dose
If you miss a dose, contact your doctor immediately to find out what steps to take next.
To use this medication correctly, follow your doctor's instructions and read all the information provided. It is essential to follow the dosage instructions carefully. This medication is administered as an intravenous injection, which means it is given as a shot into a vein.
Storing and Disposing of Your Medication
If you need to store this medication at home, consult with your doctor, nurse, or pharmacist to determine the best storage method.
Missing a Dose
If you miss a dose, contact your doctor immediately to find out what steps to take next.
Lifestyle & Tips
- Follow your doctor's instructions for diet, especially regarding calcium and phosphorus intake.
- Take any prescribed phosphate binders as directed, usually with meals.
- Attend all scheduled blood tests to monitor your PTH, calcium, and phosphorus levels.
- Do not take any over-the-counter calcium or vitamin D supplements without consulting your doctor.
- Avoid magnesium-containing antacids or laxatives unless approved by your doctor.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial dose based on baseline intact parathyroid hormone (iPTH) levels. Administer as a bolus injection 3 times per week, no more frequently than every other day.
Dose Range:
0.04 - 0.1 mg
Condition-Specific Dosing:
CKD Stage 5 (on dialysis):
Initial dose (mcg) = Baseline iPTH (pg/mL) / 80. Administer 3 times per week. Adjust dose based on iPTH, calcium, and phosphorus levels. Doses typically range from 0.04 mcg/kg to 0.1 mcg/kg.
CKD Stages 3 and 4 (oral formulation preferred, but IV can be used):
Not specifically detailed for IV in this context, as oral is standard. For IV, follow CKD Stage 5 guidelines if used off-label or in specific clinical scenarios.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Safety and efficacy not established in pediatric patients. Limited data suggest similar pharmacokinetics to adults, but dosing recommendations are not available.
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment needed for CKD Stages 3 and 4, as it's indicated for these stages. Dosing is based on iPTH levels.
Moderate:
No specific dose adjustment needed for CKD Stages 3 and 4, as it's indicated for these stages. Dosing is based on iPTH levels.
Severe:
Indicated for CKD Stage 5 (on dialysis). Dosing is based on iPTH levels.
Dialysis:
Indicated for patients on hemodialysis or peritoneal dialysis. Dosing is based on baseline iPTH and adjusted to maintain iPTH within target range (150-300 pg/mL) while monitoring calcium and phosphorus.
Hepatic Impairment:
Mild:
No dose adjustment required.
Moderate:
No dose adjustment required.
Severe:
No dose adjustment required, as hepatic impairment does not significantly alter paricalcitol pharmacokinetics.
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 the parathyroid glands, leading to a reduction in parathyroid hormone (PTH) synthesis and secretion. It also has effects on bone and mineral metabolism, but its selective action on the parathyroid VDR minimizes its calcemic and phosphatemic effects compared to calcitriol, making it suitable for managing secondary hyperparathyroidism in chronic kidney disease.
Pharmacokinetics
Absorption:
Bioavailability:
100% (IV administration)
Tmax:
Not applicable (IV bolus)
FoodEffect:
Not applicable (IV administration)
Distribution:
Vd:
Approximately 3.1 L/kg
ProteinBinding:
Greater than 99% (primarily to albumin)
CnssPenetration:
Limited
Elimination:
HalfLife:
Approximately 15 hours (range 13-20 hours) in CKD Stage 5 patients.
Clearance:
Not readily quantifiable due to complex elimination pathways.
ExcretionRoute:
Primarily biliary/fecal (approximately 70%), with a smaller portion (approximately 30%) excreted renally.
Unchanged:
Less than 2% of the administered dose is excreted unchanged in urine and feces.
Pharmacodynamics
OnsetOfAction:
Within hours (PTH suppression)
PeakEffect:
Within days to weeks (for stable PTH reduction)
DurationOfAction:
Several days (due to half-life and sustained PTH suppression)
Confidence:
Medium
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when 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
+ Fatigue
+ Headache
+ Upset stomach 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. Many people experience no side effects or only mild ones. If you notice any of the following side effects or any other unusual symptoms, contact your doctor for advice:
Diarrhea
Upset stomach or vomiting
Dizziness or headache
Nose or throat irritation
Sleep disturbances
Joint pain
Eye redness
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, 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.
While rare, some people may experience severe and potentially life-threatening side effects when 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
+ Fatigue
+ Headache
+ Upset stomach 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. Many people experience no side effects or only mild ones. If you notice any of the following side effects or any other unusual symptoms, contact your doctor for advice:
Diarrhea
Upset stomach or vomiting
Dizziness or headache
Nose or throat irritation
Sleep disturbances
Joint pain
Eye redness
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, 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 very tired, nausea, vomiting, constipation, muscle weakness, confusion, increased thirst or urination.
- Signs of high phosphorus (hyperphosphatemia): itching, bone pain, red eyes.
- Signs of high magnesium (hypermagnesemia): muscle weakness, dizziness, slow heartbeat.
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 symptoms you experienced.
Certain health conditions, including high calcium levels or high vitamin D levels.
* If you are breastfeeding. Note that you should not breastfeed while taking this medication.
This list is not exhaustive, and it is crucial to discuss all your medications (including prescription, over-the-counter, natural products, and vitamins) and health issues with your doctor and pharmacist. They will help determine if it is safe to take this medication with your other medications and health conditions. Always consult your doctor before starting, stopping, or changing the dose of any medication.
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 symptoms you experienced.
Certain health conditions, including high calcium levels or high vitamin D levels.
* If you are breastfeeding. Note that you should not breastfeed while taking this medication.
This list is not exhaustive, and it is crucial to discuss all your medications (including prescription, over-the-counter, natural products, and vitamins) and health issues with your doctor and pharmacist. They will help determine if it is safe to take this medication with your other medications and health conditions. Always consult your doctor before starting, stopping, or changing the dose of any medication.
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 products that contain aluminum, such as certain antacids, inform your doctor to minimize potential interactions.
If you consume grapefruit juice or eat grapefruit regularly, discuss this with your doctor, as it may affect the medication's efficacy.
Adhere to the dietary plan recommended by your doctor to ensure optimal treatment outcomes.
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 associated with using this medication during pregnancy.
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 products that contain aluminum, such as certain antacids, inform your doctor to minimize potential interactions.
If you consume grapefruit juice or eat grapefruit regularly, discuss this with your doctor, as it may affect the medication's efficacy.
Adhere to the dietary plan recommended by your doctor to ensure optimal treatment outcomes.
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 associated with using this medication during pregnancy.
Overdose Information
Overdose Symptoms:
- Hypercalcemia (severe nausea, vomiting, anorexia, constipation, dehydration, muscle weakness, fatigue, mental status changes, coma)
- Hyperphosphatemia
- Hypermagnesemia
What to Do:
Immediately discontinue paricalcitol. Institute measures to lower serum calcium (e.g., low-calcium diet, hydration, loop diuretics, corticosteroids). Hemodialysis may be considered in severe cases. Call 1-800-222-1222 (Poison Control) or seek emergency medical attention.
Drug Interactions
Contraindicated Interactions
- Hypercalcemia
- Vitamin D toxicity
Major Interactions
- Phosphate binders (calcium-containing): Increased risk of hypercalcemia.
- Magnesium-containing antacids/laxatives: Increased risk of hypermagnesemia (especially in CKD patients).
- Digitalis glycosides: Hypercalcemia can potentiate digitalis toxicity.
Moderate Interactions
- CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin, ritonavir): May increase paricalcitol exposure, requiring dose adjustment.
- Thiazide diuretics: May increase risk of hypercalcemia.
Minor Interactions
- Not specifically identified as minor, but general caution with other agents affecting calcium/phosphorus.
Monitoring
Baseline Monitoring
Serum intact parathyroid hormone (iPTH)
Rationale: To establish baseline and guide initial dosing.
Timing: Prior to initiation of therapy.
Serum calcium
Rationale: To ensure normocalcemia before initiation and to monitor for hypercalcemia.
Timing: Prior to initiation of therapy.
Serum phosphorus
Rationale: To ensure normophosphatemia before initiation and to monitor for hyperphosphatemia.
Timing: Prior to initiation of therapy.
Serum alkaline phosphatase
Rationale: To assess bone turnover and overall mineral metabolism.
Timing: Prior to initiation of therapy.
Routine Monitoring
Serum calcium
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), avoiding hypercalcemia.
Action Threshold: If corrected serum calcium exceeds 10.5 mg/dL, reduce or interrupt paricalcitol dose until calcium normalizes.
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), avoiding hyperphosphatemia.
Action Threshold: If serum phosphorus exceeds 5.5 mg/dL, consider dose reduction or interruption, and optimize phosphate binder therapy.
Serum intact parathyroid hormone (iPTH)
Frequency: Every 2-4 weeks during dose initiation/adjustment, then every 1-3 months once stable.
Target: 150-300 pg/mL (KDOQI guidelines for CKD Stage 5).
Action Threshold: Adjust dose to maintain iPTH within target range. If iPTH falls below 150 pg/mL, reduce or interrupt dose.
Serum alkaline phosphatase
Frequency: Periodically (e.g., every 3-6 months).
Target: Within normal limits or trending towards normal.
Action Threshold: Significant changes may indicate issues with bone turnover or mineral metabolism.
Symptom Monitoring
- Symptoms of hypercalcemia (e.g., nausea, vomiting, constipation, lethargy, muscle weakness, confusion, polyuria, polydipsia)
- Symptoms of hyperphosphatemia (e.g., pruritus, bone pain, vascular calcification)
- Symptoms of hypermagnesemia (e.g., muscle weakness, hypotension, bradycardia, respiratory depression)
Special Patient Groups
Pregnancy
Category C. There are no adequate and well-controlled studies in pregnant women. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Potential risk, but human data are limited.
Second Trimester:
Potential risk, but human data are limited.
Third Trimester:
Potential risk, but human data are limited.
Lactation
It is not known whether paricalcitol is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from paricalcitol, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Infant Risk:
Unknown, potential for adverse effects.
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 have been 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 VDRA, meaning it has a lower propensity to cause hypercalcemia and hyperphosphatemia compared to non-selective vitamin D analogs like calcitriol.
- Dosing is highly individualized and requires careful titration based on iPTH, calcium, and phosphorus levels.
- Frequent monitoring of serum calcium and phosphorus is crucial, especially during dose initiation and adjustments, to prevent hypercalcemia and hyperphosphatemia.
- Patients should be educated on the importance of dietary restrictions (calcium, phosphorus) and adherence to phosphate binder therapy.
- If hypercalcemia or hyperphosphatemia occurs, the dose of paricalcitol should be reduced or interrupted until levels normalize. Other medications affecting calcium/phosphorus should also be reviewed.
- Avoid concomitant use of magnesium-containing products due to the risk of hypermagnesemia in CKD patients.
Alternative Therapies
- Calcitriol (Rocaltrol, Calcijex)
- Doxercalciferol (Hectorol)
- Cinacalcet (Sensipar) - a calcimimetic, different mechanism but also used for secondary hyperparathyroidism.
- Etelcalcetide (Parsabiv) - another calcimimetic.
Cost & Coverage
Average Cost:
Check current pricing databases (e.g., Red Book, Micromedex) per 1ml vial (5mcg/ml)
Generic Available:
Yes
Insurance Coverage:
Tier 2 or 3 (Specialty drug, may require prior authorization)
General Drug Facts
If your symptoms or health problems persist or worsen, it is essential to contact your doctor for further guidance. To ensure safe use, never share your medication with others, and do not take medication prescribed for someone else. Store all medications in a secure location, out of reach of children and pets, to prevent accidental ingestion.
Proper disposal of unused or expired medications is crucial. Do not dispose of them by flushing down the toilet or pouring down the drain unless specifically instructed to do so. If you are unsure about the correct disposal method, consult your pharmacist for advice. Many communities offer drug take-back programs, which your pharmacist can help you locate.
Some medications may come with an additional patient information leaflet. Check with your pharmacist to see if this applies to your prescription. If you have any questions or concerns about your medication, do not hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider.
In the event of a suspected overdose, immediately contact your local poison control center or seek emergency medical attention. Be prepared to provide detailed information about the overdose, including the name of the medication, the amount taken, and the time it was taken, to ensure prompt and effective treatment.
Proper disposal of unused or expired medications is crucial. Do not dispose of them by flushing down the toilet or pouring down the drain unless specifically instructed to do so. If you are unsure about the correct disposal method, consult your pharmacist for advice. Many communities offer drug take-back programs, which your pharmacist can help you locate.
Some medications may come with an additional patient information leaflet. Check with your pharmacist to see if this applies to your prescription. If you have any questions or concerns about your medication, do not hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider.
In the event of a suspected overdose, immediately contact your local poison control center or seek emergency medical attention. Be prepared to provide detailed information about the overdose, including the name of the medication, the amount taken, and the time it was taken, to ensure prompt and effective treatment.