Plenaxis Side Effects

Generic name: abarelix

Note: This document contains side effect information about abarelix. Some dosage forms listed on this page may not apply to the brand name Plenaxis.

Applies to abarelix: powder for suspension, solution.

Warning

Intramuscular routeKitImmediate-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).

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

Other 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

For Healthcare Professionals

Applies to abarelix: intramuscular powder for injection.

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]

General

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

Musculoskeletal

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

Cardiovascular

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

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

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

Immediate-onset reactions have been reported to have occurred following any administration of abarelix (the active ingredient contained in Plenaxis) 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]

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.^[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]