Health Guide
Drug Guide

Abarelix (Intramuscular route, injection route)


a-ba-REL-ix, SOE-dee-um KLOR-ide

Brand Names:

Dosage Forms:


Intramuscular routeKit

Immediate-onset systemic allergic reactions, some resulting in hypotension and syncope, have occurred after administration of abarelix. These immediate-onset reactions have been reported to occur following any administration of abarelix , including after the initial dose. The cumulative risk of such a reaction increases with the duration of treatment. Following each injection of abarelix, patients should be observed for at least 30 minutes in the office and in the event of an allergic reaction, managed appropriately.

Abarelix is indicated for the palliative treatment of men with advanced symptomatic prostate cancer, in whom LHRH agonist therapy is not appropriate and who refuse surgical castration, and have one or more of the following: (1) risk of neurological compromise due to metastases, (2) ureteral or bladder outlet obstruction due to local encroachment or metastatic disease, or (3) severe bone pain from skeletal metastases persisting on narcotic analgesia.

The effectiveness of abarelix in suppressing serum testosterone to castrate levels decreases with continued dosing in some patients. Effectiveness beyond 12 months has not been established. Treatment failure can be detected by measuring serum total testosterone concentrations just prior to administration on Day 29 and every 8 weeks thereafter .

Immediate-onset systemic allergic reactions, some resulting in hypotension and syncope, have occurred after administration of abarelix. These reactions can occur after any dose, and patients should be observed for at least 30 minutes following each injection and managed appropriately if an allergic reaction occurs. Measure serum total testosterone concentrations to assess effectiveness and detect treatment failure. Only physicians who have enrolled in the PLENAXIS(TM) PLUS Program may prescribe PLENAXIS(TM) .

Uses of This Medicine:

Abarelix is a type of medicine called a gonadotropin-releasing hormone (GnRH) antagonist that lowers the male hormone testosterone in your blood. Testosterone makes most prostate cancers grow. Other ways to treat your prostate cancer are taking other hormone medicines to lower testosterone or surgery to remove your testicles. Abarelix is used when these other ways to treat prostate cancer cannot be used or are refused.

Abarelix is to be given only under the supervision of your doctor. It is to be injected into your buttocks.

This medicine was available only with your doctor's prescription.

This medicine was withdrawn from the U.S. market in May 2005, and is available only to patients who are currently receiving the medicine.

Before Using This Medicine:

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

It is very important that you read the Patient Information for abarelix before you start getting injections. You will need to sign the last page if you agree with treatment with abarelix. If you have any questions about this ask your doctor.


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Studies on this medicine have only been done in adult patients, and there is no specific information comparing the use of abarelix in children with other age groups. Abarelix is not for use in children.

Older adults

This medicine has been tested and has not been shown to cause different side effects or problems in older people than it does in younger adults.


Pregnancy CategoryExplanation
All TrimestersXStudies in animals or pregnant women have demonstrated positive evidence of fetal abnormalities. This drug should not be used in women who are or may become pregnant because the risk clearly outweighs any possible benefit.



There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Sodium Chloride

Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.

Other medicines

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Other interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other medical problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

Proper Use of This Medicine:

Abarelix is only prescribed by doctors who are part of Plenaxis PLUS Program (Plenaxis User Safety Program) that is run by the pharmaceutical (drug) company that makes the medicine.

Abarelix is given as an injection (shot) in your buttocks. Your doctor or nurse will give you the injection. It is important that you keep your appointment with your doctor's office when your injection is due. If you are unable to keep your appointment, contact your doctor's office to be rescheduled as soon as possible. It is very important that you follow the schedule that your doctor planned for your treatment.

You must always wait in your doctor's office for at least 30 minutes after getting each abarelix injection (shot). If a serious or life-threatening allergic reaction happens it is usually soon after getting an abarelix injection. Tell your doctor right away if you feel warm, faint or lightheaded or if you have chest tightness, shortness of breath, redness of your skin, or swelling of your face, eyelids, tongue, or throat. These could be signs of an allergic reaction.

Abarelix is only used for treating advanced symptomatic prostate cancer when a patient cannot have or refuses other treatments for prostate cancer


The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Precautions While Using This Medicine:

It is very important that your doctor check you at regular visits. Your doctor will also want to do regular blood tests about every 8 weeks to check your testosterone level to see if abarelix is working for you. If you weigh more than 225 pounds there may be a greater chance that abarelix may stop working. Your doctor may also want to do blood tests to check your liver function before and during treatment with abarelix.

This medicine may cause loss in bone mineral density with extended treatment. Loss in bone mineral density can lead to the thinning of bones (osteoporosis). If you have any questions about this ask your doctor.

This medicine can cause a change in heart rhythm called prolongation of the QTc interval. This condition may change the way your heart beats and can cause fainting and serious side effects in some patients. Contact your doctor right away if you have any of these symptoms or any questions about this.

Side Effects of This Medicine:

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Less common
Fainting or loss of consciousness
fast or irregular breathing
skin rash
swelling of the eyes or eyelids
tightness in the chest and/or wheezing
trouble with breathing

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
Back pain
bladder pain
breast enlargement
breast pain
bloating or swelling of the face, arms, hands, lower legs, or feet
bloody or cloudy urine
body aches or pain
burning while urinating
decrease in frequency of urination
decrease in urine volume
difficult, burning, or painful urination
difficulty having a bowel movement (stool)
difficulty in passing urine (dribbling)
ear congestion
feeling of warmth
frequent urge to urinate
loss of voice
lower back or side pain
nasal congestion
nipple enlargement
rapid weight gain
redness of the face, neck, arms, and occasionally, upper chest
runny nose
sore throat
tingling of the hands or feet
trouble in holding or releasing urine
trouble with sleeping
unusual tiredness or weakness
unusual weight gain or loss

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Last Updated: 6/12/2013

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