FENSOLVI KIT
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FENSOLVI KIT (FENSOLVI KIT).
Leuprolide acetate is a GnRH agonist that initially stimulates and then suppresses pituitary gonadotropin release by downregulating GnRH receptors, leading to decreased testosterone and estradiol levels.
| Metabolism | Primarily metabolized by hydrolysis to inactive peptide fragments and excreted in urine; no significant CYP450 involvement. |
| Excretion | Primarily renal (~80%) and biliary/fecal (~20%) as metabolites and unchanged drug. |
| Half-life | 3-4 hours (terminal); clinical suppression of LH/FSH persists 4 weeks post-injection. |
| Protein binding | ~80% bound to albumin and other plasma proteins. |
| Volume of Distribution | 0.3-0.5 L/kg; moderate distribution indicating limited extravascular penetration. |
| Bioavailability | SubQ: 85-95% relative to IV; oral: negligible (<5%). |
| Onset of Action | SubQ: initial LH surge within 2-4 hours; therapeutic suppression by 2-4 weeks. |
| Duration of Action | Single injection suppresses gonadotropins for 1 month (28-day dosing schedule). |
| Molecular Weight | 1209.3 |
45 mg subcutaneously every 6 months.
| Dosage form | POWDER |
| Renal impairment | No dose adjustment required for renal impairment. |
| Liver impairment | No dose adjustment required for hepatic impairment. |
| Pediatric use | Weight ≥20 kg: 45 mg subcutaneously every 6 months. |
| Geriatric use | No specific dose adjustment; use standard adult dosing. |
| 1st trimester | Risk cannot be ruled out. Based on animal data and its mechanism of action, FENSOLVI (leuprolide acetate) may cause fetal harm when administered to a pregnant woman. Contraindicated in pregnancy. |
| 2nd trimester | Contraindicated in pregnancy. Can cause fetal harm based on animal studies. |
| 3rd trimester | Contraindicated in pregnancy. Can cause fetal harm based on animal studies. |
Clinical note
Comprehensive clinical and safety monograph for FENSOLVI KIT (FENSOLVI KIT).
| Placental transfer | Leuprolide acetate and its metabolites are expected to cross the placenta. In animal studies, there was evidence of fetal resorption and decreased fetal weight. |
| Breastfeeding | No data available on excretion in human milk. The manufacturer recommends discontinuing nursing due to potential for serious adverse effects in the nursing infant. |
■ FDA Black Box Warning
WARNING: TRANSIENT INCREASE IN TESTOSTERONE LEVELS DURING INITIAL TREATMENT MAY CAUSE WORSENING OF PROSTATE CANCER SYMPTOMS AND SPINAL CORD COMPRESSION.
| Serious Effects |
PregnancyKnown hypersensitivity to GnRH agonists or any component of the formulation
| Precautions | Monitor for tumor flare and spinal cord compression in prostate cancer, Risk of QT prolongation, Bone density loss with prolonged use, Hyperglycemia and diabetes, Cardiovascular events (myocardial infarction, sudden cardiac death) with androgen deprivation therapy, Seizures reported, Hypersensitivity reactions including anaphylaxis, Embryo-fetal toxicity; verify pregnancy status before initiating |
| Food/Dietary | No clinically significant food interactions. Take with or without food. Grapefruit juice may alter hormone metabolism; avoid excessive consumption. |
Loading safety data…
| Lactation Rating | L5 - Contraindicated |
| Teratogenic Risk | Pregnancy Category X. FENSOLVI (leuprolide acetate) is contraindicated in pregnancy due to risk of fetal harm. First trimester exposure may cause spontaneous abortion or congenital anomalies. Second and third trimester exposure is not applicable as therapy is typically discontinued. No adequate studies in pregnant women; animal studies show embryotoxicity and teratogenicity. |
| Fetal Monitoring | Pregnancy test required before initiation to rule out pregnancy. Monitor for missed menses or suspected pregnancy. If pregnancy occurs during treatment, discontinue immediately and inform patient of fetal risk. |
| Fertility Effects | Leuprolide suppresses gonadotropin secretion, leading to reversible inhibition of spermatogenesis (male) and ovulation (female). After discontinuation, return of fertility is expected but may be delayed. Long-term use may cause prolonged anovulation; recovery time varies. |
| Clinical Pearls | FENSOLVI KIT (histrelin acetate) is a GnRH agonist implant used for central precocious puberty. Onset of effect: gonadal suppression may require 2-4 weeks; transient flare in first week possible. Implant provides sustained release for 12 months. Monitor bone age and Tanner staging. Discontinue after age 11 in females, 12 in males. |
| Patient Advice | Implant is inserted subdermally in the inner upper arm under local anesthesia and remains for 12 months. · A transient increase in pubertal signs may occur during the first week after insertion. · Report signs of infection (redness, swelling, pain) at implant site immediately. · Long-term effects on fertility are unknown; discuss with physician. · Regular follow-up is required to monitor growth and pubertal suppression. |