PARSABIV
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PARSABIV (PARSABIV).
Calcium-sensing receptor (CaSR) agonist; increases the sensitivity of the CaSR to extracellular calcium, thereby decreasing parathyroid hormone (PTH) secretion.
| Metabolism | Primarily metabolized via amide hydrolysis and oxidation, with involvement of CYP3A4, CYP2D6, and CYP1A2 as minor pathways. |
| Excretion | Renal: negligible (<2% unchanged); fecal: primary route via biliary elimination of intact drug and metabolites; not dialyzable. |
| Half-life | Terminal elimination half-life of 3-5 days, supporting once-weekly subcutaneous dosing. |
| Protein binding | Approximately 90-95% bound to albumin. |
| Volume of Distribution | Approximately 0.29-0.46 L/kg, indicating distribution limited to extracellular fluid. |
| Bioavailability | Subcutaneous: approximately 50% (range 40-60%). |
| Onset of Action | Subcutaneous: reduction in serum parathyroid hormone (PTH) observed within 2-4 hours post-dose. |
| Duration of Action | Subcutaneous: PTH suppression sustained for at least 8 hours, with return to baseline by 24-36 hours; clinically, thrice-weekly dosing maintains PTH control. |
Initial dose 5 mg intravenously three times per week, titrated by 2.5 or 5 mg increments every 4 weeks to a maximum of 15 mg three times per week to achieve target parathyroid hormone levels.
| Dosage form | SOLUTION |
| Renal impairment | Contraindicated in patients with estimated glomerular filtration rate (eGFR) less than 15 mL/min/1.73 m². No dose adjustment required for eGFR ≥ 15 mL/min/1.73 m². |
| Liver impairment | No specific guidelines available; use with caution in severe hepatic impairment (Child-Pugh class C) due to lack of data. |
| Pediatric use | Safety and efficacy not established in pediatric patients; no approved dosing recommendations. |
| Geriatric use | No specific dose adjustments recommended; clinical studies included patients aged 65 years and older; no overall differences in safety or efficacy observed. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PARSABIV (PARSABIV).
| Breastfeeding | No data on etelcalcetide presence in human milk, effects on breastfed infants, or milk production. Animal studies show etelcalcetide is present in rat milk. M/P ratio unknown. Because of the potential for serious adverse reactions including hypocalcemia in nursing infants, advise patients not to breastfeed during treatment and for two weeks after the last dose. |
| Teratogenic Risk | In animal reproduction studies, intravenous etelcalcetide administered to pregnant rats during organogenesis at doses 2.5 times the maximum recommended human dose (MRHD) based on AUC caused increased incidences of fetal skeletal variations and reduced fetal body weight. In rabbits, no adverse fetal effects were observed at doses up to 0.7 times the MRHD. No adequate and well-controlled studies in pregnant women exist. In the first trimester, exposure poses unknown but potential teratogenic risk. During the second and third trimesters, the drug may cause fetal hypocalcemia due to PTH suppression. Use only if potential benefit justifies potential risk. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypocalcemia"]
| Precautions | ["Hypocalcemia","Seizures potentially due to severe hypocalcemia","QT interval prolongation","Gastrointestinal bleeding","Adynamic bone disease"] |
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| Fetal Monitoring | Monitor serum calcium levels frequently in pregnant women, as etelcalcetide reduces PTH and may cause hypocalcemia. Assess fetal growth and amniotic fluid volume via ultrasound due to potential for adverse fetal effects. Postnatally, monitor infant for symptoms of hypocalcemia such as jitteriness, seizures, or apnea. |
| Fertility Effects | In animal studies, etelcalcetide did not impair fertility or reproductive performance in male or female rats at exposures up to 23 times the MRHD based on AUC. No human data available. |