Overdose

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When treating severe spasticity with Lioresal^® Intrathecal (baclofen injection), it is mandatory that all patients, caregivers, and treating physicians receive adequate information regarding the risks of the mode of treatment. Importantly, instruction should be given on signs and symptoms of overdose, procedures to be followed in the event of an overdose, and proper home care of the pump and insertion site.¹

What are the signs of Lioresal^® Intrathecal overdose?

Signs of overdose may appear suddenly or insidiously, and a massive overdose may present as coma. In most cases reported, coma was reversible without sequelae after drug was discontinued.
Less sudden and/or less severe forms of overdose may present with signs of drowsiness, lightheadedness, dizziness, somnolence, respiratory depression, seizures, rostral progression of hypotonia, and loss of consciousness progressing to coma.¹ Symptoms of Lioresal^® Intrathecal overdose were reported in a sensitive adult patient after receiving a 25 mcg intrathecal bolus.¹

Lioresal^® Intrathecal overdose can mimic symptoms associated with sepsis, intracranial hemorrhage, hypoglycemia, Cushing’s triad, electrolyte imbalance, and seizure disorder. Overdose symptoms may include nausea and vomiting, dizziness, respiratory depression, hypothermia, rostral progression of hypotonia, and somnolence that have advanced to seizures and coma requiring ventilator support.²

Should overdose appear likely, the patient should be taken immediately to an emergency room or an intensive care unit for assessment. While there is no specific antidote for treating overdoses of Lioresal^® Intrathecal, certain steps should ordinarily be undertaken¹:

Residual Lioresal^® Intrathecal solution should be removed from the pump as soon as possible
Patients with respiratory depression should be intubated if necessary until the drug is eliminated
If lumbar puncture is not contraindicated, consideration should be given to withdrawing 30 to 40 mL of CSF to reduce the CSF baclofen concentration

Management of overdose starts with supportive measures, including maintenance of the airway, respiration, and circulation. Subsequent measures may include reduction or temporary interruption of ITB therapy by pump reprogramming. Draining of CSF from the catheter access port and sequential lumbar puncture or lumbar drains are optional. Patients with overdose must then be monitored closely for rebound withdrawal. Most patients recover completely with supportive care, fluids, and ventilator support.²

Important Safety Information for Lioresal^® Intrathecal (baclofen injection)

Abrupt discontinuation of intrathecal baclofen, regardless of the cause, has resulted in sequelae that include high fever, altered mental status, exaggerated rebound spasticity, and muscle rigidity, that in rare cases has advanced to rhabdomyolysis, multiple organ-system failure and death.

Prevention of abrupt discontinuation of intrathecal baclofen requires careful attention to programming and monitoring of the infusion system, refill scheduling and procedures, and pump alarms. Patients and caregivers should be advised of the importance of keeping scheduled refill visits and should be educated on the early symptoms of baclofen withdrawal. Special attention should be given to patients at apparent risk (e.g. spinal cord injuries at T-6 or above, communication difficulties, history of withdrawal symptoms from oral or intrathecal baclofen). Consult the technical manual of the implantable infusion system for additional postimplant clinician and patient information (see WARNINGS).

Indications and Usage

Lioresal^® Intrathecal (baclofen injection) is a muscle relaxant and antispastic that is indicated for use in the management of severe spasticity of cerebral or spinal origin.

Lioresal^® Intrathecal is intended for use by the intrathecal route in single bolus test doses (via spinal catheter or lumbar puncture) and, for chronic use, only in implantable pumps approved by the FDA specifically for the administration of Lioresal^® Intrathecal into the intrathecal space.

Lioresal^® Intrathecal via an implantable pump should be reserved for patients unresponsive to oral baclofen therapy or those who experience intolerable CNS side effects at effective doses.

Patients with spasticity due to traumatic brain injury should wait at least one year after the injury before consideration of long term intrathecal baclofen therapy.

Prior to implantation of a device for chronic intrathecal infusion of Lioresal^® Intrathecal, patients must show a response to Lioresal^® Intrathecal in a screening trial.

Please review the dosing and administration section of the Lioresal^® Intrathecal prescribing information for further details.

Select Warnings and Precautions

It is mandatory that all patients, caregivers, and treating physicians receive adequate information regarding the risks of the mode of treatment. Instruction should be given on signs and symptoms of overdose, procedures to be followed in the event of an overdose, and proper home care of the pump and insertion site.

Due to the possibility of life-threatening CNS depression, cardiovascular collapse, and/or respiratory failure, physicians must be adequately trained and educated in chronic intrathecal infusion therapy.

Patients should be infection-free prior to both a screening trial and a pump implantation. The presence of infection may interfere with an assessment of the patient’s response to bolus Lioresal^® Intrathecal, increase the risk of surgical complications and complicate dosing.

Reservoir refilling must be performed by fully trained and qualified personnel following the directions provided by the pump manufacturer. Extreme caution must be used when filling an FDA approved implantable pump, following strict aseptic technique and ensuring refill directly into the reservoir and not the catheter access port.

An attempt should be made to discontinue concomitant oral antispasticity medication to avoid possible overdose or adverse drug interactions, either prior to screening or following implant and initiation of chronic Lioresal^® Intrathecal infusion.

Following pump implantation, and for each adjustment of the dosing rate of the pump and/or concentration of Lioresal^® Intrathecal, the patient should be monitored closely until it is certain the patient’s response to the infusion is acceptable and reasonably stable.

Early symptoms of baclofen withdrawal may include return of baseline spasticity, pruritus, hypotension and paresthesias.

Priapism may develop or recur if treatment with intrathecal baclofen is interrupted.

Signs of overdose may appear suddenly or insidiously, and a massive overdose may present as coma. Less sudden and/or less severe forms of overdose may present with signs of drowsiness, lightheadedness, dizziness, somnolence, respiratory depression, seizures, rostral progression of hypotonia and loss of consciousness progressing to coma.

Should overdose appear likely, the patient should be taken immediately to a hospital for assessment and emptying of pump reservoir.

Except in overdose related emergencies, the dose of Lioresal^® Intrathecal should ordinarily be reduced slowly if the drug is discontinued for any reason.

Adverse Reactions

Common Adverse Reactions

The most frequent drug adverse events vary by indication but include: hypotonia (34.7%), somnolence (20.9%), headache (10.7%), convulsion (10.0%), dizziness (8.0%), urinary retention (8.0%), nausea (7.3%), and paresthesia (6.7%). Dosing and programming errors may result in clinically significant overdose or withdrawal. Acute massive overdose may result in coma and may be life threatening.

Drowsiness has been reported in patients on Lioresal^® Intrathecal. Patients should be cautioned regarding the operation of automobiles or other dangerous machinery and activities made hazardous by decreased alertness. Patients should also be cautioned that the central nervous system depressant effects of Lioresal^® Intrathecal may be additive to those of alcohol and other CNS depressants.

Serious Adverse Reactions

Seizures have been reported during overdose and with withdrawal from Lioresal^® Intrathecal as well as in patients maintained on therapeutic doses of Lioresal^® Intrathecal.

Fatalities have been reported with Lioresal^® Intrathecal use.

Postmarketing Experience

The following adverse events have been reported during post-approval use of Lioresal^® Intrathecal.

Musculoskeletal – The onset of scoliosis or worsening of a pre-existing scoliosis has been reported.
Urogenital – Sexual dysfunction in men and women including decreased libido and orgasm dysfunction have been reported.

Use in Specific Populations

There are no adequate and well controlled studies in pregnant women. Lioresal^® Intrathecal should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Nursing mothers should exercise caution, as oral baclofen has been shown to pass into milk at therapeutic doses.

Safety and effectiveness in pediatric patients below the age of 4 have not been established.

Patients suffering from psychotic disorders, schizophrenia, or confusional states should be treated cautiously with Lioresal^® Intrathecal and kept under careful surveillance.

Lioresal^® Intrathecal should be given with caution in patients with impaired renal function. Dose reduction may be necessary.

Lioresal^® Intrathecal should be used with caution in patients with a history of autonomic dysreflexia.

For more information, including BOXED WARNING, refer to Lioresal^® Intrathecal (baclofen injection) prescribing information.

Lioresal Intrathecal (baclofen injection)

What are the signs of Lioresal^® Intrathecal overdose?

Emergent (Acute) Troubleshooting —Overdose²

Important Safety Information for Lioresal^® Intrathecal (baclofen injection)

Important Safety Information for Lioresal^® Intrathecal (baclofen injection)

Indications and Usage

Contraindications

Select Warnings and Precautions

Adverse Reactions

Use in Specific Populations

Overdose

What are the signs of Lioresal® Intrathecal overdose?

Emergent (Acute) Troubleshooting —Overdose2

Important Safety Information for Lioresal® Intrathecal (baclofen injection)

Indications and Usage

Contraindications

Select Warnings and Precautions

Adverse Reactions

Use in Specific Populations

What are the signs of Lioresal^® Intrathecal overdose?

Emergent (Acute) Troubleshooting —Overdose²

Important Safety Information for Lioresal^® Intrathecal (baclofen injection)