Histrelin (Subcutaneous)

Overview

Histrelin is a synthetic hormone sold under the brand name Supprelin LA. It mimics the hormone released in the brain by the hypothalamus gland. Histrelin works by stimulating the brain to lower the levels of sex hormones such as estrogen and testosterone in the blood. The implant containing hormone is placed under the skin to release small doses of histrelin in the body over a period of 12 months.

Available only with the doctor's prescription, this GnRH agonist is sold under the brand name Supprelin LA used to treat Precocious Puberty (CPP) in children. CPP is a condition in which puberty begins at an abnormally early age (before eight years in girls and nine years in boys). The drug reduces the amounts of sex hormones (testosterone and estrogen) in the blood.

Conditions Treated By Histrelin

  • Precocious puberty (CPP)

Type Of Medicine

  • Gonadotropin Releasing Hormone Agonist

Side Effects

Alongside the intended effects, histrelin, like other drugs may cause some undesired side effects. Some of these side effects are mild and tend to go away as the body gets used to the medication. However, some histrelin side effects are severe and may require medical attention.

During the first few weeks of histrelin therapy, the patient may experience an increase in the levels of some hormones. During this period, the patient may exhibit more signs of puberty, such as breast enlargement and light vaginal bleeding. However, these signs should stop within four weeks of treatment.

On rare occasions, patients may develop serious complications with the pituitary gland (pituitary apoplexy). This usually occurs during the first two weeks of treatment. It is important that you seek immediate medical attention if you experience any of the side effects associated with pituitary apoplexy. These include sudden and sharp headache, sudden mood swings (i.e loss of concentration or severe confusion), loss of vision, fainting and severe vomiting.

Serious allergic reactions to histrelin are rare. However, be sure to seek immediate medical attention if notice symptoms of severe allergic reactions such as rashes, swelling of the face, tongue and throat, breathing problems and severe dizziness.

That said, check with your healthcare provider immediately if any of the following histrelin side effects occur:

Rare histrelin side effects

  • Blood in urine or dark urine
  • Loss of appetite
  • Reduced amount or frequency of urine
  • Nausea
  • Increased thirst
  • Lower back or side pain
  • Swelling of the face and limbs
  • Breathing difficulty
  • Unusual fatigue and weakness
  • Weight gain
  • Vomiting
  • Abdominal or stomach pain
  • Seizures
  • Frequent stomach bloating
  • Yellow skin or eyes

As already mentioned, some histrelin side effects do not need medical attention. These side effects tend to go away as the body adjusts to treatment. Additionally, your healthcare provider should be able to advise you how to manage or prevent these side effects. Check with your healthcare provider if you are troubled by these histrelin side effects:

  • Reduced testicle size
  • Feeling of warmth
  • An irritation, infection, or redness on the skin where the implant was placed
  • Sudden sweating
  • Redness on the face, arms and upper chest
  • Reduced libido
  • Difficulty having a bowel movement
  • Mild headache
  • Inability to sustain an erection and loss of sexual ability/performance
  • Trouble sleeping
  • Unusually warm skin

Check with your healthcare provider for advice on these side effects. You may also report the side effects to the FDA at 1-800-FDA-1088

Histrelin dosage

The recommended dosage for histrelin is one implant placed every 12 months. Each implant comes with 50 mg of histrelin acetate. The implant is subcutaneously inserted in the upper part of the arm from where it continuously releases small doses of histrelin acetate into the body for a period of 12 months. At the end of the 12 months, the implant should be removed from the patient's arm upon which a decision can be made to insert a fresh one or discontinue the therapy altogether. Discontinuation of histrelin treatment should be considered at the discretion of the healthcare provider at the appropriate time for the onset of puberty (about 11 years for girls and 12 years for boys).

Proper use of this medication

A histrelin implant should only be placed by a trained healthcare professional. The implant should be placed under the skin in the upper arm.

Your healthcare provider will treat the area of the implant with a numbing medicine before cutting a small incision to insert the implant. The incision will then be closed using surgical strips or stitches. A pressure bandage will then placed over the spot and left in place for about 24 hours.

Keep the arm clean and dry after the implant is inserted. Keep of water (swimming or bathing) for 24 hours. Additionally, avoid lifting heavy objects or engaging in strenuous activities for up to seven days after receiving the implant.

You may experience some pain, bruising or redness on the spot where the implant is placed. Contact your healthcare provider if the wound does not heal within two weeks after receiving the implant.

Histrelin interactions

Histrelin therapy may trigger a suppression of the pituitary-gonadal system. Thus, the results of diagnostic tests of the gonadal and pituitary gonadotrophic functions conducted during and immediately after histrelin treatment may be inaccurate.

Interaction with other medications

Although certain medications should never be used together, in other cases two different medicines may be combined even if this might cause an interaction. Under such circumstances, your healthcare provider will recommend a change of dosage for one or both medications, or recommend appropriate precautions. Inform your healthcare provider about the medications you are currently on before getting an implant. These include over-the-counter medications, supplements, multivitamins as well as herbal medicines.

Additionally, do not take the following medications without the approval of your healthcare provider:

  • Amisulpride
  • Amufampridine
  • Bepridil
  • Dronedarone
  • Cisapride
  • Mesoridazine
  • Piperaquine
  • Pimozide
  • Saquinavir
  • Ziprasidone
  • Sparfloxacin
  • Thioridazine
  • Terfenadine

Other medical conditions affecting the effectiveness of histrelin

Certain preexisting medical conditions may affect the use, and efficiency, of histrelin. Be sure to inform your healthcare provider if you have any of the following preexisting medical conditions:

  • Blocked bladder
  • Diabetes
  • Heart attack or a history of cardiovascular condition
  • High blood sugar levels(hyperglycemia)
  • Kidney problems including reduced urine flow
  • CNS problems especially in the spine from cancer lesions
  • A history of stroke
  • Electronic imbalance
  • Congestive heart failure
  • Heart rhythm problems

Finally, inform your healthcare provider of any allergies you might be having, including drug, food, and animal allergies.

Histrelin warnings

Patients on GnRH agonist therapy are at a higher risk of developing hyperglycemia.

Spinal cord compression has been reported in patients on histrelin treatment. Continued use of this medication may result in weakness and paralysis with fatal complications.

Some patients have experienced convulsions after treatment with GnRH agonist like histrelin. This is specifically common in patients with epilepsy, a history of cerebrovascular disorders and tumors and anomalies of the central nervous system.

There have been reports of myocardial infarction (MI), sudden death as a result of cardiac arrest, as well as stroke in men treated with GnRH agonists.

Histrelin may cause a miscarriage or defects to the unborn baby. As such, it should never be used during pregnancy. Effective birth control should be used while on this medication.

The location where the implant has been placed should be kept clean and dry for at least 24 hours. The patient should not bathe or swim during this period. The bandage may be removed after 24 hours. However, the surgical strips should never be removed as they tend to fall off on their own after a couple of weeks.

The patient should avoid lifting heavy objects or engage in exercises that strain the implanted arm for a minimum of seven days. After the cut area has healed, the patient may resume their normal activities. The healthcare provider should give comprehensive instructions.

Like other GnRH agonists, histrelin affects estradiol concentrations in females as well as testosterone levels in both males and females during the first week of therapy. Patients may experience the onset of new symptoms or worsening of existing ones during the first week of treatment. However, these symptoms tend to go away as the body adjusts to the therapy.

Histrelin implant insertion and removal is a surgical procedure, one that requires attention to prevent potential complications. The implant should be aseptically inserted and removed. Additionally, the proper surgical technique is required to minimize adverse effects related to the insertion and removal of the implant.

During histrelin therapy, patients should be routinely monitored for evidence of clinical as well as biochemical suppression of CPP manifestations.

Luteinizing hormone, follicle stimulating hormone and testosterone, or estradiol levels should be monitored for one month after the implant then six months thereafter. In addition, the patient's height and bone age should be assessed every six months.

To be sure that histrelin is safe for you, tell your healthcare provider if you have ever had:

  • Psychosis or mental illness
  • Epilepsy or other seizure related disorders
  • Tumor or blood vessel disorder especially in the brain
  • If you are presently on a medication that can cause a seizure such as an antidepressant

It is important that you schedule regular hospital visit so your healthcare provider can monitor your progress. This is essential for establishing if the implant is in the right place and is working as intended. Your healthcare provider may also recommend certain medical tests to look out for any unwanted side effects.

For children on histrelin, this medication can trigger a rise in the levels of some hormones in the blood. This is specifically common during the onset of the therapy and is characterized by more signs of puberty such as enlargement of breast and light vaginal bleeding in girls. These symptoms should improve within four weeks of treatment. However, if this does not happen, be sure to contact your healthcare provider for help.

For male patients on histrelin:

  • While on histrelin therapy, some of the symptoms might worsen especially during the onset of treatment. The patient might also experience new symptoms like bone pain, a feeling of numbness throughout the body, back pain, pain while passing urine or blood spots in the urine. These symptoms should go away after a few weeks. Call your healthcare provider if you experience any new symptoms, or if these symptoms worsen.
  • This medication may trigger a rise in the patient's blood sugar levels. If you are diabetic and notice a change in your sugar levels or urine tests, call your healthcare provider immediately.
  • Histrelin may increase the patient's risk of suffering from stroke or a heart attack. Check with your healthcare provider immediately if you experience discomfort or chest pain, speaking difficulty, sudden headache, strong pain and discomfort in the upper arms, back or neck, jaw, breathing difficulty and shortness of breath, profuse sweating, and frequent vomiting while on this medication.
  • Contact your healthcare provider immediately if you notice a change in your heart rhythm. This is often characterized by fast, pounding, and at times uneven heartbeats as well as dizziness. Be sure to inform your doctor if you or a close family member has a history of heart rhythm problem such as QT prolongation.
  • Be sure to inform every doctor and dentist who treats you that you are on histrelin therapy.

Histrelin storage

Histrelin should be packaged in a corrugated shipping carton that comes with two inner cartons:

  • A large carton that contains the implantation kit, and
  • A smaller carton that contains the vial containing the implant

Histrelin is stabled when stored under refrigeration. The medication should be sealed and stored at 2 to 8 degrees C. The medication should be stored in the hospital environment away from moisture and direct sunlight.

Summary

Histrelin is a subcutaneous (under-the-skin) that contains a gonadotrophin releasing hormone (GnRH). It is administered to treat children who suffer from central precocious puberty (CPP). This is a condition that triggers early puberty (before 8 years in girls, and 9 years in boys). Signs of early puberty may include appearance of pubic hair, early periods as well as breast enlargement. Histrelin works by lowering the levels of sex hormones, estrogen and testosterone, in the blood in order to cause a delay in puberty.

While histrelin is an important medication for countering the early onset of puberty, it is not to be used by everyone. For instance, this medicine should not be administered to children who are allergic to gonadotropin releasing hormone (GnRH), GnRH agonist medications, or ingredients in histrelin. In addition, this medication should not be administered to children under two years of age. Women who are or may become pregnant during the 12 months of therapy should not use this medication since it can cause birth defects or trigger a miscarriage.

It is important that the healthcare provider performs tests on the patient to be sure that the child has CPP before initiating the therapy. Histrelin implant lasts for 12 months. At the end of the 12 months, the implant should be removed, upon which the healthcare provider may decide to discontinue the therapy or introduce a fresh implant.

Being subcutaneous, this medication should be placed under the skin in the inner part of the upper arm. The healthcare provider will provide a local anesthesia in the area where the implant is to be placed before proceeding with the procedure.

Like with other medications, histrelin does come with its share of side effects. Some of these side effects are mild and tend to disappear as the body gets used to the medication. However, some histrelin side effects tend to be severe and may require doctor's attention.

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