Histrelin implant (Vantas) is used to treat the symptoms associated with advanced prostate cancer. Histrelin implant (Supprelin LA) is used to treat central precocious puberty (CPP; a condition causing children to enter puberty too soon, resulting in faster than normal bone growth and development of sexual characteristics) in girls usually between 2 and 8 years of age and in boys usually between 2 and 9 years of age. Histrelin implant is in a class of medications called gonadotropin-releasing hormone (GnRH) agonists. It works by decreasing the amount of certain hormones in the body.

Histrelin comes as an implant (a small, thin, flexible tube containing medication) that is inserted by a doctor on the inside of the upper arm. The doctor will use a medication to numb the arm, make a small cut in the skin, then insert the implant subcutaneously (just under the skin). The cut will be closed with stitches or surgical strips and covered with a bandage. The implant may be inserted every 12 months. After 12 months, the current implant should be removed and can be replaced with another implant to continue treatment. Histrelin implant (Supprelin LA) when used in children with precocious puberty, will likely be stopped by your child's doctor before 11 years of age in girls and 12 years of age in boys.

Keep the area around the implant clean and dry for 24 hours after insertion. Do not swim or bathe during this time. Leave the bandage in place for at least 24 hours. If surgical strips are used, leave them on until they fall off on their own. Avoid heavy lifting and physical activity (including heavy play or exercise for children) with the treated arm for 7 days after receiving the implant. Avoid bumping the area around the implant for a few days after insertion.

Histrelin may cause an increase in certain hormones in the first few weeks after insertion of the implant. Your doctor will monitor you carefully for any new or worsening symptoms during this time.

Sometimes histrelin implant is hard to feel under the skin so the doctor may have to use certain tests, such as ultrasound or MRI scans (radiology techniques designed to show the images of body structures) to find the implant when it is time to remove it. Occasionally, histrelin implant may come out through the original insertion site on its own. You may or may not notice this happening. Call your doctor right away if you think this may have happened to you.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

Before receiving histrelin implant,

• tell your doctor and pharmacist if you are allergic to histrelin, goserelin (Zoladex), leuprolide (Eligard, Lupaneta Pack, Lupron), nafarelin (Synarel), triptorelin (Trelstar, Triptodur Kit), anesthetics such as lidocaine (Xylocaine), any other medications, or any of the ingredients in histrelin implant. Ask your pharmacist for a list of the ingredients.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: amiodarone (Nexterone, Pacerone), anagrelide (Agrylin), bupropion (Aplenzin, Forfivo,Wellbutrin, Zyban, in Contrave), chloroquine, chlorpromazine, cilostazol, ciprofloxacin (Cipro), citalopram (Celexa), clarithromycin, disopyramide (Norpace), dofetilide (Tikosyn), donepezil (Aricept), dronedarone (Multaq), escitalopram (Lexapro), flecainide (Tambocor), fluconazole (Diflucan), fluoxetine (Prozac, Sarafem, Selfemra, in Symbyax), fluvoxamine (Luvox), haloperidol (Haldol), ibutilide (Corvert), levofloxacin, methadone (Dolophine, Methadose), moxifloxacin (Avelox), ondansetron (Zuplenz, Zofran), paroxetine (Brisdelle, Paxil, Pexeva), pentamidine (Pentam), pimozide (Orap), procainamide, quinidine (in Nuedexta), sertraline (Zoloft), sotalol (Betapace, Sorine, Sotylize), thioridazine, vilazodone (Viibryd), and vortioxetine (Trintellix). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with histrelin, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
• tell your doctor if you have a low level of potassium or magnesium in your blood. or if you have or have ever had diabetes, high blood pressure, high cholesterol, a prolonged QT interval (a rare heart problem that may cause irregular heartbeat, fainting, or sudden death), cancer that has spread to the spine (backbone), urinary obstruction (blockage that causes difficulty urinating), seizures, brain or blood vessel problems or tumors, mental illness, or heart disease.
• you should know that histrelin is not to be used in women who are pregnant or can become pregnant. Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you think you have become pregnant while receiving histrelin implant, call your doctor immediately. Histrelin implant can harm the fetus.

If you miss an appointment to receive an implant of histrelin or to have histrelin implant removed, you should call your healthcare provider right away to reschedule your appointment. If continuing treatment, the new histrelin implant should be inserted within a few weeks.

Unless your doctor tells you otherwise, continue your normal diet.

Histrelin implant may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• bruising, soreness, tingling, or itching at the place where implant was inserted
• scarring at the place where implant was inserted
• hot flashes (a sudden wave of mild or intense body heat)
• tiredness
• light vaginal bleeding in girls
• enlarged breasts
• decrease in size of testicles
• decreased sexual ability or interest
• constipation
• weight gain
• difficulty falling asleep or staying asleep
• headache
• crying, irritability, impatience, anger, aggressive behavior

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• pain, bleeding, swelling, or redness at the place where implant was inserted
• hives
• rash
• itching
• difficulty breathing or swallowing
• bone pain
• weakness or numbness in the legs
• pain, burning, or tingling in an arm or leg
• slow or difficult speech
• dizziness or fainting
• chest pain
• pain in the arms, back, neck, or jaw
• loss of ability to move
• difficult urination or can not urinate
• blood in urine
• decreased urination
• unusual bleeding or bruising
• extreme tiredness
• loss of appetite
• pain in the upper right part of the stomach
• yellowing of the skin or eyes
• flu-like symptoms
• depression, thinking about killing yourself or planning or trying to do so
• seizures

Histrelin implant may cause changes in your bones which can increase the chance of broken bones when used for long periods of time. Talk to your doctor about the risks of receiving this medication.

In children receiving histrelin implant (Supprelin LA) for precocious puberty, new or worsening symptoms of sexual development may occur during the first few weeks after the insertion of the implant. In girls receiving histrelin implant (Supprelin LA) for precocious puberty, light vaginal bleeding or breast enlargement may occur during the first month of treatment.

Histrelin implant may cause other side effects. Call your doctor if you have any unusual problems while receiving this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests and take certain measurements to check your body's response to histrelin implant. Your blood sugar and glycosylated hemoglobin (HbA1c) should be checked regularly.

Before having any laboratory test, tell your doctor and the laboratory personnel that you have a histrelin implant.

Ask your pharmacist any questions you have about histrelin implant.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.