Supprelin LA Patient Tips

Medically reviewed by Carmen Pope, BPharm. Last updated on May 7, 2025.

1. How it works

• Supprelin LA is a brand name for histrelin acetate which is a gonadotropin-releasing hormone (GnRH) agonist and a type of reversible hormone deprivation treatment that may be used to treat central precocious puberty (CPP) in children aged 2 years and older.
• Supprelin LA is an agonist of GnRH. GnRH is produced by the hypothalamus and acts on the surface of gonadotropin cells in the pituitary gland stimulating the release of luteinizing hormone (LH) and follicular stimulating hormone (FSH). This stimulates the production and release of gonadal steroids - testosterone and dihydrotestosterone in males, and estrone and estradiol in premenopausal females. Following an initial stimulatory phase, Supprelin LA desensitizes the responsiveness of the pituitary gonadotropin cells which causes a decrease in hormone production by the testicles and ovaries.
• Supprelin LA belongs to the class of medications known as gonadotropin-releasing hormone agonists (GnRH agonists).

2. Upsides

• Approved to treat central precocious puberty (CPP) in children aged 2 years and older.
• Available as a small, flexible, implant, 1.3 inches (3.5cm) long that is implanted by a healthcare provider just under the skin of the upper arm.
• One full year of medication is contained in one Supprelin LA implant. This compares favorably to Lupron Depot-Ped which must be given 12 times a year (once every month) by intramuscular (IM) injection.
• Keeps the testicles and ovaries from making sex hormones by blocking other hormones that are needed to make them.
• Effective at delaying puberty until the child reaches a healthy age for puberty to begin. Children with CPP go through puberty earlier than 8 years (females) or 9 years (males). Their bone age is also advanced which can result in a lower height attainment in adulthood.
• Delivers approximately 65 mcg of histrelin acetate per day.
• Although one implant lasts 12 months, there is some flexibility around this because the implant has been designed to allow for a few additional weeks of histrelin release. When the implant is removed, another one should be inserted unless the child has reached the appropriate age for puberty (11 years for females and 12 years for males).

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

• Reactions at the implant or injection site, which may cause redness, pain, swelling, bruising, and scarring are common side effects reported. Flushing, or a feeling of warmth, a headache, and a decrease in testicle size are also commonly reported.
• May also cause an initial worsening of CPP symptoms, such as light vaginal bleeding, or breast enlargement or tenderness in girls, but this resolves within the first 4 weeks.
• Mood and psychiatric effects have been noted in people prescribed GnRH agonists, including Supprelin LA. Symptoms include emotional lability, such as anger, aggression, crying, impatience, and irritability.
• Rarely, convulsions have occurred, including in children with a history of seizures or epilepsy, on other medications that lower the seizure threshold (such as bupropion and SSRIs), and in those with no history of seizures or interacting medications. Other rare side effects include intracranial hypertension or
• Before implantation, total sex steroids, LH and FSH following stimulation with a GnRH analog, and bone age need to be assessed. Other investigations should include height and weight, brain imaging (to rule out intracranial tumor), pelvic/testicular/adrenal ultrasound (to rule out steroid-secreting tumors), human chorionic gonadotropin levels (to rule out chorionic gonadotropin secreting tumor), and adrenal steroids to exclude congenital adrenal hyperplasia.
• Insertion of the implant is a surgical procedure and should only be done by a suitably trained healthcare provider. Proper surgical techniques reduce the risk of side effects happening. On occasion locating and removing the implant has been difficult, and in some cases, it has broken on removal. Spontaneous extrusion of the implant is rare. Note that the implant is not radiopaque.
• Perform laboratory tests (LH, FSH, estradiol, or testosterone at 1-month post-implantation and then every 6 months thereafter. Assess height and weight every 6 to 12 months.
• Not to be inserted into children who are hypersensitive to GnRH or GnRH agonist analogs. Do not use during pregnancy. There is no data on use during breastfeeding.
• The safety of using Supprelin LA in children less than 2 years old has not been established.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Supprelin LA is approved to treat central precocious puberty in children aged 2 years and older. It is a small, flexible, implant, 1.3 inches (3.5cm) long that is implanted just under the skin of the upper arm by a healthcare provider. One implant lasts 12 months. Common side effects include reactions at the implant site, which may cause redness, pain, swelling, bruising, and scarring are common side effects reported. Flushing, or a feeling of warmth, a headache, and a decrease in testicle size are also commonly reported.

5. Tips

• Your healthcare provider will talk you through the procedure of placing the Supprelin LA implant just under the skin of your child's inner upper arm. The implant is small and flexible (1.3 inches [3.5cm]), barely noticeable, and will continuously release the active ingredient, histrelin acetate, for one year. The entire procedure can be done in a doctor’s office using a local anesthetic.
• Before implantation, your doctor will measure your child's total sex steroids, LH and FSH following stimulation with a GnRH analog, and assess their bone age in addition to other diagnostic investigations.
• After 12 months of therapy, the implant should be removed and a new one inserted if your child has not yet reached an acceptable age for puberty (11 years for girls or 12 for boys).
• Supprelin LA starts to work within 4 weeks of implantation and by that time you should see signs that your child’s puberty is stopping. Do not be alarmed if during the first week of Supprelin LA treatment you an increase in signs of puberty in your child, such as light vaginal bleeding or breast enlargement in girls. This is to be expected because initially, Supprelin LA causes an increase in some hormones, but after 1 week, hormone levels decrease and puberty starts to abate.
• Common side effects include reactions at the implant or injection site, which may cause redness, pain, swelling, bruising, and scarring. Monitor the incision site and report anything of concern to your healthcare provider. Flushing, or a feeling of warmth, a headache, and a decrease in testicle size are also commonly reported.
• Mood and psychiatric effects have been noted in children prescribed Supprelin LA. Symptoms include emotional lability, such as anger, aggression, crying, impatience, and irritability. Talk to your doctor if this happens.
• Rare side effects include seizures and intracranial hypertension. Monitor your child for signs and symptoms of intracranial hypertension such as headache, blurred or double vision, loss of vision, pain behind the eye or pain with eye movement, ringing in the ears, dizziness, or nausea, and tell your doctor immediately if these symptoms or seizures occur.
• Your child should refrain from getting the inserted arm wet for 24 hours and from strenuous exertion of the inserted arm for 7 days after implant insertion to allow the incision to fully close. Allow the surgical strips to fall off on their own after several days.

6. Response and effectiveness

• Administration of Supprelin LA results in an initial increase in circulating levels of LH and FSH, leading to a transient increase in concentration of gonadal steroids (testosterone and dihydrotestosterone in males, and estrone and estradiol in premenopausal females).
• Research has shown that suppression of luteinizing hormone (LH) was induced in all children with central precocious puberty (CPP) 4 weeks after implantation and continued through to month 12. Other outcomes, such as levels of estrogen and testosterone, bone age advancement, linear growth, and clinical progression of puberty all decreased, indicating stabilization of disease. By month 9, 100% of females showed estradiol suppression which decreased slightly to 97% by month 12. Testosterone suppression was reported in 100% of males at month 12.

7. Interactions

Medicines that interact with Supprelin LA may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with Supprelin LA. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

No formal drug-drug, drug-food, or drug-herb interaction studies have been performed with Supprelin LA. But interactions reported with other GnRH agonists include:

• albuterol
• antibiotics, such as erythromycin, levofloxacin, or metronidazole
• anticancer treatments such as doxorubicin
• antidepressants, such as amitriptyline, citalopram, escitalopram, or venlafaxine
• antidiarrheal medications, such as loperamide
• antifungals, such as azithromycin
• antihistamines, such as hydroxyzine
• antipsychotics, such as aripiprazole, clozapine, haloperidol, thioridazine, or ziprasidone
• bisacodyl
• bupropion
• chloroquine or hydroxychloroquine
• cisapride
• heart medications, such as amiodarone or flecainide
• HIV medications, such as efavirenz or saquinavir
• insulin and other antidiabetic medications such as glyburide, or metformin
• lactulose
• lithium
• magnesium salts
• methadone
• mineral oil
• moxifloxacin
• multiple sclerosis agents such as fingolimod or ozanimod
• ondansetron
• papaverine
• pimozide
• quinidine
• salmeterol
• senna
• tamoxifen
• tolbutamide
• tramadol.

Supprelin LA suppresses the pituitary-gonadal system which will affect diagnostic tests of pituitary gonadotropic and gonadal functions conducted during treatment and for three months after discontinuation.

Note that this list is not all-inclusive and includes only some common medications that may interact with Supprelin LA. You should refer to the prescribing information for Supprelin LA for a complete list of interactions.

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Frequently asked questions

• Is Supprelin LA the same as Lupron?
• How quickly does Supprelin LA work?

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Supprelin LA only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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