Skip to main content

Plenaxis Side Effects

Generic name: abarelix

Note: This document provides detailed information about Plenaxis Side Effects associated with abarelix. Some dosage forms listed on this page may not apply specifically to the brand name Plenaxis.

Applies to abarelix: powder for suspension, solution.

Important warnings This medicine can cause some serious health issues

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.

  • PLENAXIS™
    • Only physicians who have enrolled in the Plenaxis™ PLUS Program (Plenaxis™ User Safety Program), based on their attestation of qualifications and acceptance of prescribing responsibilities, may prescribe Plenaxis™.
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).

Common side effects of Plenaxis

Some side effects of abarelix 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
  • chills
  • cough
  • decrease in frequency of urination
  • decrease in urine volume
  • diarrhea
  • difficult, burning, or painful urination
  • difficulty having a bowel movement (stool)
  • difficulty in passing urine (dribbling)
  • dizziness
  • ear congestion
  • feeling of warmth
  • fever
  • frequent urge to urinate
  • headache
  • loss of voice
  • lower back or side pain
  • nasal congestion
  • nausea
  • nipple enlargement
  • pain
  • rapid weight gain
  • redness of the face, neck, arms, and occasionally, upper chest
  • runny nose
  • sneezing
  • sore throat
  • sweating
  • tingling of the hands or feet
  • trouble in holding or releasing urine
  • trouble with sleeping
  • unusual tiredness or weakness
  • unusual weight gain or loss

Serious side effects of Plenaxis

Along with its needed effects, abarelix (the active ingredient contained in Plenaxis) 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 while taking abarelix:

Less common

  • fainting or loss of consciousness
  • fast or irregular breathing
  • itching
  • skin rash
  • swelling of the eyes or eyelids
  • tightness in the chest and/or wheezing
  • trouble with breathing
Managing side effects (general information)

For healthcare professionals

Applies to abarelix: intramuscular powder for injection.

General

General side effects including pain (31%) and fatigue (10%) have been reported.[Ref]

Endocrine

Endocrine side effects have included hot flushes (79%), sleep disturbance (44%), breast enlargement (30%), and breast pain/nipple tenderness (20%) as pharmacological consequences of androgen deprivation.[Ref]

Musculoskeletal

Musculoskeletal side effects including back pain (17%) have been reported.[Ref]

Cardiovascular

Cardiovascular side effects including peripheral edema (15%) and prolongation of the QT interval have been reported.[Ref]

Physicians should carefully consider whether the risks of abarelix outweigh the benefits in patients with baseline QTc values >450 msec and in patients taking class IA or class III antiarrhythmic medications.[Ref]

Gastrointestinal

Gastrointestinal side effects including constipation (15%), diarrhea (11%), and nausea (10%) have been reported.[Ref]

Nervous system

Nervous system side effects including dizziness (12%) and headache (12%) have been reported.[Ref]

Respiratory

Respiratory side effects including upper respiratory tract infection (12%) have been reported.[Ref]

Genitourinary

Genitourinary side effects including dysuria (10%), micturition frequency (10%), urinary retention (10%), and urinary tract infection (10%) have been reported.[Ref]

Hypersensitivity

Hypersensitivity side effects including immediate-onset allergic reactions (3.7%), sometimes resulting in hypotension and syncope, have been reported to have occurred after administration of abarelix (the active ingredient contained in Plenaxis) [Ref]

The allergic reaction included urticaria, pruritus, hypotension, and syncope.

Immediate-onset reactions have been reported to have occurred following any administration of abarelix, including the initial dose. The cumulative risk for 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. If an allergic reaction associated with hypotension and/or syncope does occur, supportive measures such as leg elevation, oxygen, IV fluids, antihistamines, corticosteroids, and epinephrine should be administered as needed.[Ref]

Hepatic

Hepatic side effects including clinically meaningful increases in serum transaminases have been reported in a small percentage of patients.[Ref]

Hematologic

Hematologic side effects including slight decreases in hemoglobin and mean increases in serum triglycerides of approximately 10% have been reported.[Ref]

References

1. (2003) "Product Information. Plenaxis (abarelix)." Praecis Pharmaceuticals Inc

Further information

Plenaxis side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

Medical Disclaimer