Goserelin

ZOLADEX

What it isGnRH receptor agonist implant; prostate and breast cancer, endometriosis.

Why this oneA subcutaneous depot gives one to three months of suppression from a single implant.

What limits itAn initial testosterone or estrogen flare requires cover. Bone loss and vasomotor symptoms with prolonged use.

FDA-approved for

FDA dosing	Population	Start	Target	Max
Stage B2-C (T2b-T4) prostate cancer, with radiotherapy + flutamide	Men	3.6 mg SC implant 8 weeks pre-radiotherapy	3.6 mg depot then 10.8 mg depot 28 days later; OR four 3.6 mg depots q28 days (2 before, 2 during radiotherapy)	Per regimen
Advanced prostate cancer	Men	3.6 mg SC implant q28 days	3.6 mg SC q28 days, long-term	3.6 mg q28 days
Endometriosis	Women >=18 yr	3.6 mg SC implant q28 days	3.6 mg SC q28 days x 6 months	6-month course (retreatment not recommended)
Endometrial thinning before ablation	Women	3.6 mg SC implant x 1-2 depots (4 weeks apart)	1 depot: surgery at 4 weeks; 2 depots: surgery 2-4 weeks after second	2 depots
Advanced breast cancer	Women	3.6 mg SC implant q28 days	3.6 mg SC q28 days, long-term	3.6 mg q28 days

Renal No adjustment needed

Hepatic No adjustment needed

Endometriosis limited to 6 months; retreatment not recommended (no safety data)

SC implant into anterior abdominal wall below navel, by physician, aseptic technique; every effort to keep 28-day schedule (few days' delay permissible)
Caution: inferior epigastric artery proximity; extra care with low BMI or full-dose anticoagulation; do not penetrate muscle/peritoneum
If a vessel is penetrated (blood in chamber), withdraw and inject new syringe elsewhere; monitor for abdominal hemorrhage
Endometriosis: consider HRT add-back to reduce bone mineral loss

Pregnancy, unless used for palliative treatment of advanced breast cancer (fetal harm; pregnancy-loss risk)
Known hypersensitivity to GnRH, GnRH agonist analogues, or any component (anaphylaxis reported)

Exclude pregnancy before use for benign gynecologic conditions; nonhormonal contraception during and 12 weeks after therapy
Tumor flare: transient testosterone/estrogen surge; ureteral obstruction and spinal cord compression reported
Hyperglycemia/new diabetes in men on GnRH agonists — monitor glucose/HbA1c
Increased MI, sudden cardiac death, stroke risk in men — monitor
Hypercalcemia in patients with bone metastases
Severe cutaneous adverse reactions (SJS/TEN, DRESS, AGEP) — interrupt if suspected; discontinue permanently if confirmed
QT/QTc prolongation with androgen deprivation therapy
Injection site/vascular injury incl. hemorrhage and hemorrhagic shock
Depression may occur or worsen in women
Increased cervical resistance — care when dilating cervix
Bone mineral density loss (endometriosis use)

Men (>10%): hot flashes, sexual dysfunction, decreased erections, lower urinary tract symptoms
Women (>20%): hot flushes, headache, sweating, acne, emotional lability, depression, decreased libido, vaginitis, breast atrophy, seborrhea, peripheral edema
Tumor flare at initiation (both sexes)

Pregnancy Contraindicated unless palliative advanced breast cancer; can cause fetal harm and pregnancy loss

Lactation Unknown if in human milk; discontinue nursing or drug, weighing importance to mother

NO BOXED WARNINGS

Principal riskInitial hormone flare; bone loss with prolonged use

Direct muscarinic antagonism0 / 4