goserelin

High Alert

Palliative treatment of advanced prostate cancer.
Locally confined stage T2b–T4 (stage B2–C) prostate cancer (in combination with flutamide).
Palliative treatment of advanced breast cancer in peri menopausal and postmenopausal women.
Endometriosis.
Produces thinning of the endometrium before endometrial ablation for dysfunctional uterine bleeding.

Action ⬆ ⬇

Acts as a synthetic form of luteinizing hormone–releasing hormone (LHRH, GnRH). Inhibits the production of gonadotropins by the pituitary gland. Initially, levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone increase. Continued administration leads to decreased production of testosterone and estradiol.

Therapeutic effects:

Decreased spread of cancer of the prostate or breast.
Regression of endometriosis with decreased pain.
Thinning of the endometrium.

Pharmacokinetics ⬆ ⬇

Absorption: Well absorbed from SUBQ implant. Absorption is slower in first 8 days, then is faster and continuous for remainder of 28-day dosing cycle.

Distribution: Unknown.

Metabolism/Excretion: Some metabolism by the liver (<10%), some excretion by kidneys (>90%, only 20% as unchanged drug).

Half-Life: 4.2 hr.

Time/Action Profile ⬆ ⬇

(↓ in serum testosterone levels)

ROUTE	ONSET	PEAK	DURATION
SUBQ	unknown	2–4 wk	length of therapy

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Undiagnosed vaginal bleeding;
OB: Pregnancy;
Lactation: Lactation.

Use Cautiously in:

Congenital long QT syndrome, HF, hypokalemia, or hypomagnesemia;
Concurrent use of other drugs known to prolong the QTc interval;
Low BMI (↑ risk of bleeding complications);
Concurrent use of anticoagulant therapy (↑ risk of bleeding complications);
Pedi: Safety and effectiveness not established in children.

Adv. Reactions/Side Effects ⬆ ⬇

CV: vasodilation, chest pain, hypertension, MI, palpitations, peripheral edema, QT interval prolongation

Derm: hot flushing, sweating, acne, rash

Endo: ↓libido, erectile dysfunction, breast swelling, breast tenderness, infertility, ovarian cysts, ovarian hyperstimulation syndrome (with gonadotropins)

GI: anorexia, constipation, diarrhea, nausea, ulcer, vomiting

GU: renal insufficiency, urinary obstruction

Hemat: anemia

Local: injection site/vascular injury

Metab: ↑weight, gout, hyperglycemia, hyperlipidemia

MS: ↑bone pain, ↓bone density, arthralgia

Neuro: headache, anxiety, depression (women), dizziness, fatigue, insomnia, mood swings, SEIZURES, STROKE, SUICIDAL IDEATION/BEHAVIOR (WOMEN), weakness

Resp: dyspnea

Misc: chills, fever

Interactions ⬆ ⬇

Drug-drug:

None reported.

Route/Dosage ⬆ ⬇

SC (Adults ): 3.6 mg every 4 wk or 10.8 mg every 12 wk. Endometrial thinning: 1 or 2 depots given 4 wk apart; if 1 depot used, surgery is performed at 4 wk; if 2 depots used, surgery is performed 2–4 wk after 2nd depot.

Availability ⬆ ⬇

Implant: 3.6 mg; 10.8 mg

Assessment ⬆ ⬇

Monitor for signs and symptoms of injection site injury/abdominal hemorrhage (abdominal pain, abdominal distension, dyspnea, dizziness, hypotension, and/or any altered levels of consciousness) following administration. Advise patient to report symptoms immediately to health care professional.
Cancer: Monitor patients with vertebral metastases for increased back pain and decreased sensory/motor function.
Monitor intake and output ratios and assess for bladder distention in patients with urinary tract obstruction during initiation of therapy.
Endometriosis: Assess patient for signs and symptoms of endometriosis before and periodically during therapy. Amenorrhea usually occurs within 8 wk of initial administration and menses usually resume 8 wk after completion.

Lab Test Considerations:

Initially ↑, then ↓ LH and FSH. This leads to castration levels of testosterone in men 2–4 wk after initial increase in concentrations.
- Monitor serum acid phosphatase and prostate-specific antigen concentrations periodically during therapy. May cause transient ↑ in serum acid phosphatase concentrations, which usually return to baseline by the 4th wk of therapy and may ↓ to below baseline or return to baseline if elevated before therapy.
- May cause hypercalcemia in patients with breast or prostate cancer with bony metastases.
- May cause an ↑ in serum HDL, LDL, and triglycerides.
- May cause hyperglycemia. Monitor blood glucose and HbA1c periodically during therapy.

Implementation ⬆ ⬇

SC: Implant is inserted in upper SUBQ tissue of anterior abdominal wall below the navel line every 28 days. Local anesthesia may be used before injection.
- If the implant needs to be removed for any reason, it can be located by ultrasound.

Patient/Family Teaching ⬆ ⬇

Explain purpose of goserelin to patient. Emphasize importance of adhering to the schedule of monthly or every-3-mo administration.
Advise patient that bone pain may increase at initiation of therapy. This will resolve with time. Patient should discuss use of analgesics to control pain with health care professional.
Advise female patients to notify health care professional if regular menstruation persists.
Inform diabetic patients of potential for hyperglycemia. Encourage close monitoring of serum glucose.
Advise patient that medication may cause hot flashes. Notify health care professional if these become bothersome. Hormone replacement therapy may be added to decrease vasomotor symptoms and vaginal dryness without compromising beneficial effect.
Instruct patient to notify health care professional promptly if difficulty urinating or if symptoms of myocardial infarction or stroke (chest pain, difficulty breathing, weakness, loss of consciousness) occur.
Rep: May cause fetal harm. Advise premenopausal women to notify health care professional if pregnancy is planned or suspected and to avoid breastfeeding. Effective nonhormonal contraception should be used during and for 12 wk after treatment ends.

Evaluation/Desired Outcomes ⬆ ⬇

Decrease in the spread of prostate cancer.
Reduction of symptoms of advanced breast cancer in peri- and postmenopausal women.
Decrease in the signs and symptoms of endometriosis. Symptoms are usually reduced within 4 wk of implantation.
Thinning of the endometrium before endometrial ablation for dysfunctional uterine bleeding.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇