histrelin

Absorption: Highly absorbed (92%) from implant. Peak absorption occurs at 12 hours, and continues over 1–year period.

Distribution: Unknown.

Protein Binding: 29%.

Metabolism/Excretion: Unknown.

Half-Life: 3.92 hours.

Time/Action Profile ⬆ ⬇

(↓ in LH, FSH, and sex-steroid levels)

ROUTE	ONSET	PEAK	DURATION
SUBQ	unknown	12 hr	52 wk

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity to any component of the product, GnRH, or GnRH agonist analogs;
OB: Pregnancy ( risk of pregnancy loss);

Use Cautiously in:

Seizures, cerebrovascular disorders, CNS tumor, or concurrent use of bupropion or SSRIs.
Lactation: Safety not established in breastfeeding;
Pedi: Children 2 yr (safety and effectiveness not established).

Adv. Reactions/Side Effects ⬆ ⬇

Derm: ↑sweating, acne, pruritus, rash

EENT: visual disturbances

Endo: ↑breast size, breast discharge, breast pain

Local: itching, erythema, and swelling at implantation site

Neuro: aggression, anger, anxiety, depression, dizziness, impatience, insomnia, intracranial hypertension, irritability, lethargy, malaise, SEIZURES

Interactions ⬆ ⬇

Drug-drug:

Concurrent use withbupropion or SSRIs may ↑ risk of seizures.

Route/Dosage ⬆ ⬇

SC (Children ≥2 yr): 50 mg implant inserted every 12 mo.

Availability ⬆ ⬇

SUBQ implant: 50 mg/implant

Assessment ⬆ ⬇

Monitor patient for signs of hypersensitivity (angioedema, urticaria, hypotension, tachycardia, loss of consciousness, bronchospasm, dyspnea, flushing, pruritus). Discontinue therapy if any of these symptoms occur.
Monitor for emotional lability (crying, irritability, impatience, anger, aggression) and worsening of psychiatric symptoms periodically during therapy.
Central Precocious Puberty: Obtain a complete physical and endocrinologic examination, including height, weight, before starting, after 1 mo and every 6–12 mo during therapy.

Lab Test Considerations:

Monitor LH, FSH, estradiol, or testosterone at 1 mo after implantation and every 6 mo thereafter.
- May cause ↑ AST and LDH; usually reversible with removal of implant.

Implementation ⬆ ⬇

SC: Histrelin is given as a single yearly SUBQ implant. The implant must be removed after 12 mo of therapy. Subsequent implantation may be used to continue therapy.

Patient/Family Teaching ⬆ ⬇

Explain purpose of histrelin to patient.
Instruct patient to not to get arm wet for 24 hrs and to avoid strenuous lifting for 7 days after insertion.
Inform patient and family that if implants are not given yearly, disease may progress.
Advise patient and family that during initial agonistic phase (1–3 wk) patient may have transient symptoms, worsening or onset of new symptoms, including bone pain, neuropathy, hematuria, or urinary tract obstruction.
Inform patient and family that redness or swelling may occur at the implantation site, especially after initial implantation or implant removal. Notify health care professional if this reaction is severe or does not go away.
Inform patient and family that emotional lability and worsening of psychiatric symptoms may occur.
Instruct patient and family to contact health care professional at the first sign of skin rash, urticaria, rapid heartbeat, seizures, difficulty swallowing or breathing, or any swelling that may suggest angioedema.
Rep: May cause fetal harm and increase risk of fetal loss. Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding. May impair fertility in males.

section name header

Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇