Dosing and uses of Firmagon (degarelix)
Adult dosage forms and strengths
powder for injection
- 80mg
- 120mg
Hormone-dependent Advanced Prostate Carcinoma (Stage D)
Initial: 120 mg SC for 2 doses (ie, 2 separate injections totaling 240 mg), THEN after 28 days, begin maintenance dose of 80 mg SC q28Days
Renal Impairment
≥50 mL/min: Dose adjustment not necessary
<50 mL/min: Use caution
Hepatic Impairment
Mild-to-moderate: Dose adjustment not necessary
Severe: Safety and efficacy not established; use caution
Administration
Initiation pack contains 2 vials each with 120 mg per vial & 6 mL sterile water for injection diluent
Withdraw 3 mL of sterile water for injection diluent (supplied) & add to 1 of the 2 vials, swirl to mix - keep vial vertical at all times, do not shake
Inject SC in abdomen within 1 hour of reconstitution
Repeat for 2nd injection and use different injection site
Maintenance pack contains 1 vial of 80 mg per vial & 4.2 mL sterile water for injection diluent
Use 4.2 mL to reconstitute, withdraw 4 mL for dose of 80 mg
Pediatric dosage forms and strengths
Not indicated
Firmagon (degarelix) adverse (side) effects
>10%
Hot flashes (26%)
Injection site erythema (17%)
Injection site pain (28%)
Weight gain (11%)
Elev liver enzymes (10%)
1-10% (selected)
Arthralgia
Back pain
Fatigue
HTn
Injection site induration/swelling
Warnings
Contraindications
Hypersensitivity
Pregnancy or in women who may become pregnant
Cautions
Severe hepatic impairment
Long-term androgen deprivation treatment prolongs QT interval, this is increased risk with congenital long QT syndrome, electrolyte abnormalities, CHF, coadministration with antiarrhythmic agents from Class IA [eg, quinidine, procainamide)]or Class III [eg, amiodarone, sotalol]); consider whether benefits of androgen deprivation therapy outweigh potential risks
Bone mineral density may decrease due to androgen deprivation therapy
Risk for diabetes may increase due to androgen deprivation, which may cause obesity and insulin resistance
Hypersensitivity reactions (eg, anaphylaxis, urticaria, angioedema) reported; if a serious hypersensitivity reaction occurs, discontinue drug immediately if the injection has not been completed, and manage as clinically indicated; do not rechallenged
Pregnancy and lactation
Pregnancy category: X
Lactation: excretion in milk unknown/not recommended
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Firmagon (degarelix)
Mechanism of action
GnRH receptor antagonist, suppresses testosterone production by decreasing LH and FSH
Pharmacokinetics
Protein Bound: 90%
Vd: >1000 L
Onset of action: Within 3 days
Metabolism: Liver by peptide hydrolysis
Excretion: Feces (70-80%), urine (20-30%)
Half-life elimination: Feces (75%); urine (25%)
