Zemplar 1mcg Capsules
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
Apr 2005
DEA Schedule
Not Controlled
Overview
What is this medicine?
Paricalcitol is a man-made form of vitamin D that helps control the levels of parathyroid hormone (PTH), calcium, and phosphorus in your body. It's used to treat a condition called secondary hyperparathyroidism, which often occurs in people with kidney disease. By lowering high PTH levels, it helps keep your bones healthy and prevents other problems related to kidney disease.
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, usually with or without food.
- Do not take other vitamin D supplements or calcium supplements unless directed by your doctor.
- Follow any dietary restrictions, especially regarding calcium and phosphorus intake, as advised by your doctor or dietitian.
- Attend all scheduled lab tests to monitor your calcium, phosphorus, and PTH levels.
Available Forms & Alternatives
Available Strengths:
Generic Alternatives:
Dosing & Administration
Adult Dosing
Standard Dose:
Initial dose based on baseline intact PTH (iPTH) levels. For CKD Stage 3/4: If iPTH is 30-600 pg/mL, initial dose is 1 mcg daily. For CKD Stage 5 (dialysis): Initial dose is calculated as (baseline iPTH in pg/mL / 80) mcg three times per week, not to exceed 10 mcg. Doses are adjusted every 2-4 weeks to maintain iPTH within target range (150-300 pg/mL for CKD Stage 5).
Dose Range:
1 - 10 mg
Condition-Specific Dosing:
CKD Stage 3/4:
1 mcg daily if iPTH 30-600 pg/mL. May increase to 2 mcg daily.
CKD Stage 5 (dialysis):
Initial dose = (baseline iPTH / 80) mcg three times per week. Max 10 mcg three times per week.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established. Safety and efficacy not established in pediatric patients.
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment needed beyond standard titration based on iPTH, calcium, and phosphorus levels.
Moderate:
No specific dose adjustment needed beyond standard titration based on iPTH, calcium, and phosphorus levels.
Severe:
Used in severe renal impairment (CKD Stage 5) with dose titration based on iPTH, calcium, and phosphorus levels.
Dialysis:
Used in dialysis patients (CKD Stage 5). Initial dose is calculated based on baseline iPTH and titrated to maintain target iPTH, calcium, and phosphorus levels.
Hepatic Impairment:
Mild:
No dose adjustment necessary.
Moderate:
No dose adjustment necessary.
Severe:
No dose adjustment necessary. Pharmacokinetics are similar in patients with mild-to-moderate hepatic impairment compared to healthy subjects.
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 intestinal calcium and phosphorus absorption and bone mineralization, but with less calcemic and phosphatemic activity compared to calcitriol at therapeutic doses.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 72% (oral capsule)
Tmax:
Approximately 2-4 hours
FoodEffect:
Food does not significantly affect the absorption of paricalcitol capsules.
Distribution:
Vd:
Approximately 3.2 L/kg
ProteinBinding:
Greater than 99% (primarily to albumin)
CnssPenetration:
Limited
Elimination:
HalfLife:
Approximately 15-30 hours (terminal half-life)
Clearance:
Approximately 0.04 L/hr/kg
ExcretionRoute:
Primarily biliary/fecal (approximately 70%), with a smaller portion (approximately 30%) excreted renally.
Unchanged:
Less than 2% (renal excretion)
Pharmacodynamics
OnsetOfAction:
PTH reduction typically observed within days to weeks of initiation.
PeakEffect:
Peak PTH reduction typically observed within 2-4 weeks of stable dosing.
DurationOfAction:
Effects on PTH persist as long as the drug is administered; half-life suggests effects last for several days after a single dose.
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
+ 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. Although 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:
Diarrhea
Nausea or vomiting
Dizziness or headache
Nasal or throat irritation
Sleep disturbances
Joint pain
Eye redness
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.
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
+ 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. Although 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:
Diarrhea
Nausea or vomiting
Dizziness or headache
Nasal or throat irritation
Sleep disturbances
Joint pain
Eye redness
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:
- Signs of too much calcium (hypercalcemia): Feeling very tired, nausea, vomiting, constipation, muscle weakness, confusion, increased thirst, increased urination.
- Signs of too much phosphorus (hyperphosphatemia): Itching, bone pain, red eyes (from calcium deposits).
- Report any new or worsening symptoms to your doctor immediately.
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, 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 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, 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, 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 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 you have 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 interactions may occur.
Consuming grapefruit juice or eating grapefruit regularly may also interact with this medication, so it is crucial to discuss this with your doctor.
Adhere to the dietary plan recommended by your doctor to ensure safe and effective use of this medication.
If you are pregnant or planning to become pregnant, notify your doctor immediately. You and your doctor will need to discuss the potential benefits and risks of using this medication during pregnancy.
When taking this medication, be aware 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.
Regular blood tests will be necessary, as directed by your doctor, to monitor your condition. Be sure to discuss any concerns or questions you have 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 interactions may occur.
Consuming grapefruit juice or eating grapefruit regularly may also interact with this medication, so it is crucial to discuss this with your doctor.
Adhere to the dietary plan recommended by your doctor to ensure safe and effective use of this medication.
If you are pregnant or planning to become pregnant, notify your doctor immediately. You and your doctor will need to discuss the potential benefits and risks of using this medication during pregnancy.
When taking this medication, be aware 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:
- Early symptoms: Weakness, headache, nausea, vomiting, constipation, dry mouth, metallic taste, muscle pain, bone pain, anorexia.
- Later symptoms: Polyuria, polydipsia, dehydration, weight loss, apathy, confusion, somnolence, fever, coma, arrhythmia, hypercalcemia, hyperphosphatemia, hypercalciuria, hyperphosphatemia, soft tissue calcification.
What to Do:
Immediately discontinue paricalcitol and any calcium supplements. Initiate a low-calcium diet. Hydration with intravenous fluids may be necessary. Loop diuretics may be used to increase calcium excretion. Dialysis may be considered in severe cases. Contact a poison control center or emergency services immediately (e.g., call 1-800-222-1222 in the US).
Drug Interactions
Major Interactions
- Ketoconazole (and other strong CYP3A4 inhibitors): May increase paricalcitol exposure and risk of hypercalcemia/hyperphosphatemia. Co-administration should be avoided or paricalcitol dose reduced.
Moderate Interactions
- Other CYP3A4 inhibitors (e.g., clarithromycin, ritonavir, itraconazole, voriconazole): May increase paricalcitol exposure. Monitor calcium and phosphorus levels closely.
- Phosphate binders (calcium-containing): Increased risk of hypercalcemia. Non-calcium containing binders preferred.
- Magnesium-containing products (e.g., antacids, laxatives): Increased risk of hypermagnesemia, especially in CKD patients. Avoid concomitant use.
- Digitalis glycosides: Hypercalcemia may potentiate digitalis toxicity. Monitor ECG and serum calcium.
Minor Interactions
- Thiazide diuretics: May increase risk of hypercalcemia.
Monitoring
Baseline Monitoring
Serum intact PTH (iPTH)
Rationale: To establish baseline and guide initial dosing.
Timing: Prior to initiation of therapy.
Serum Calcium
Rationale: To establish baseline and assess risk of hypercalcemia.
Timing: Prior to initiation of therapy.
Serum Phosphorus
Rationale: To establish baseline and assess risk of hyperphosphatemia.
Timing: Prior to initiation of therapy.
Alkaline Phosphatase
Rationale: To assess bone turnover markers.
Timing: Prior to initiation of therapy.
Routine Monitoring
Serum intact PTH (iPTH)
Frequency: Every 2-4 weeks initially, then every 1-3 months once stable.
Target: CKD Stage 5: 150-300 pg/mL (KDOQI guidelines). CKD Stage 3/4: Not well-defined, aim for reduction towards normal range.
Action Threshold: If iPTH is persistently above or below target range, adjust dose. If iPTH falls below 60 pg/mL, reduce or interrupt dose.
Serum Calcium
Frequency: Weekly initially, then monthly once stable.
Target: 8.4-10.2 mg/dL (or within normal limits for the lab).
Action Threshold: If corrected serum calcium > 10.5 mg/dL, reduce or interrupt dose. If persistently high, investigate other causes.
Serum Phosphorus
Frequency: Weekly initially, then monthly once stable.
Target: 2.5-4.5 mg/dL (or within normal limits for the lab).
Action Threshold: If serum phosphorus > 5.5 mg/dL, reduce or interrupt dose. Ensure adequate phosphate binder use and dietary phosphorus restriction.
Symptom Monitoring
- Symptoms of hypercalcemia: Nausea, vomiting, constipation, anorexia, muscle weakness, fatigue, confusion, polyuria, polydipsia.
- Symptoms of hyperphosphatemia: Pruritus, bone pain, soft tissue calcification (rarely acute symptoms).
Special Patient Groups
Pregnancy
Use during pregnancy should only be considered 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. There are no adequate and well-controlled studies in pregnant women.
Trimester-Specific Risks:
First Trimester:
Potential for fetal harm based on animal data; human data lacking.
Second Trimester:
Potential for fetal harm based on animal data; human data lacking.
Third Trimester:
Potential for fetal harm based on animal data; human data lacking.
Lactation
It is not known whether paricalcitol is excreted in human milk. Due to the potential for serious adverse reactions in breastfed infants from paricalcitol, including hypercalcemia, 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:
L3 (Moderate risk) - Potential for hypercalcemia in infant; monitor infant for signs of hypercalcemia.
Pediatric Use
Safety and efficacy have not been established in pediatric patients. Use is generally 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 reduce PTH with less impact on calcium and phosphorus levels compared to non-selective vitamin D analogs like calcitriol.
- Close monitoring of serum calcium, phosphorus, and iPTH is crucial, especially during dose titration, to prevent hypercalcemia and hyperphosphatemia.
- Dietary phosphorus restriction and appropriate use of phosphate binders are essential adjuncts to paricalcitol therapy.
- Avoid concomitant use of magnesium-containing antacids/laxatives due to risk of hypermagnesemia in CKD patients.
- Patients should be educated on symptoms of hypercalcemia and instructed to report them immediately.
Alternative Therapies
- Calcitriol (Rocaltrol, Calcijex)
- Doxercalciferol (Hectorol)
- Cinacalcet (Sensipar) - a calcimimetic, acts by a different mechanism but also reduces PTH.
- Etelcalcetide (Parsabiv) - another calcimimetic, injectable.
Cost & Coverage
Average Cost:
Varies, typically $100-$500+ per 30 capsules (1 mcg)
Generic Available:
Yes
Insurance Coverage:
Tier 2 or Tier 3 (for brand), Tier 1 or Tier 2 (for generic) depending on insurance plan formulary.
General Drug Facts
If your symptoms or health condition do not improve or worsen over time, it is essential to contact your doctor for further evaluation and guidance. To ensure your safety and the effectiveness of your treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it is a good idea to check with your pharmacist for more information. If you have any questions or concerns about your medication, do not hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider for clarification. 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 name of the medication taken, the amount, and the time it occurred.