Baclofen

May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).

Cases (most from pharmacy compounded preparations) of intrathecal mass formation at the implanted catheter tip have been reported; patients may experience worsening or return of spasticity, pain, inadequate response to dose adjustments, and/or neurological deficit/dysfunction. Neurosurgical evaluation and/or an appropriate imaging study should be considered if a mass is suspected.

May cause acute urinary retention (may be related to underlying disease); use with caution in patients with urinary obstruction. Disease-related concerns:

Use intrathecal baclofen with caution in patients with a history of autonomic dysreflexia; presence of nociceptive stimuli or abrupt baclofen withdrawal may cause an autonomic dysreflexic episode.

Use with caution in patients with peptic ulcer disease, decreased GI motility, and/or gastrointestinal obstructive disorders.

Use with caution in patients with psychotic disorders, schizophrenia, or confusional states; may cause exacerbation of condition.

Use with caution in patients with renal impairment; baclofen is eliminated primarily unchanged via the kidneys. Multiple cases describing neurotoxicity due to oral baclofen accumulation in adult patients with varying levels of renal impairment have been reported in the literature. In patients with renal impairment, initiation of oral baclofen at lower doses and/or extended intervals has been suggested (Aisen 1994; Chen 1997; Chou 2006; El-Husseini 2011; Peces 1998; Su 2009; Vlavonu 2014).

Use with caution in patients with respiratory disease.

Use with caution in patients with a history of seizure disorder; monitor regularly for loss of seizure control. Seizures have been reported with withdrawal from intrathecal baclofen as well as in patients maintained on therapeutic doses of intrathecal baclofen. Special populations:

Use with caution in elderly patients; may be more sensitive to adverse CNS effects, especially at higher doses.

Intrathecal: Children should be of sufficient body mass to accommodate the implantable pump for chronic infusion. Concurrent drug therapy issues:

Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information. Other warnings/precautions:

Abrupt withdrawal of intrathecal baclofen, regardless of the cause, has resulted in sequelae (hyperpyrexia, altered mental status, exaggerated rebound spasticity, and muscle rigidity, which, in rare cases, has advanced to rhabdomyolysis), multiple organ-system failure, and death. Prevention of abrupt discontinuation requires careful attention to programming and monitoring of infusion system, refill scheduling and procedures, and pump alarms. Advise patients and caregivers of the importance of keeping scheduled refill visits and educate them on the early symptoms of baclofen withdrawal. Give special attention to patients at apparent risk (eg, 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. In most cases, symptoms of withdrawal (eg, return of baseline spasticity, hypotension, paresthesia, pruritus) appear within hours to a few days following interruption of therapy. Priapism may develop or recur if treatment with intrathecal baclofen is interrupted. Clinically, the advanced intrathecal baclofen withdrawal syndrome may resemble autonomic dysreflexia, infection (sepsis), malignant hyperthermia, neuroleptic-malignant syndrome, or other conditions associated with a hypermetabolic state or widespread rhabdomyolysis. Suggested treatment for intrathecal baclofen withdrawal is r

Intrathecal: For use only in an FDA-approved implantable pump for intrathecal baclofen administration; health care providers should be experienced with chronic intrathecal infusion therapy and resuscitative equipment should be readily available. Ensure patient is infection-free and then evaluate patient’s response to bolus intrathecal injection (screening phase) prior to implanting pump. Monitor closely during the initial phase of pump use and when adjusting the dosing rate and/or the concentration in the reservoir. Educate patients and caregivers on proper home care of the pump and insertion site. Use extreme caution when filling an implantable pump; pumps should only be refilled through the reservoir refill septum. Inadvertent injection into the subcutaneous tissue can occur if the reservoir refill septum is not properly accessed. Some pumps are equipped with a catheter access port that allows direct access to the intrathecal catheter; direct injection into this catheter access port or inadvertent injection into the subcutaneous tissue may cause a life-threatening overdose. Except in overdose related emergencies, intrathecal baclofen should be reduced slowly if discontinuation is necessary.

Oral: Efficacy of oral baclofen has not been established in patients with stroke, Parkinson disease, or cerebral palsy; therefore, use is not recommended. Not indicated for spasticity associated with rheumatic disorders. Use with caution when spasticity is utilized to sustain upright posture and balance in locomotion, or when spasticity is necessary to obtain increased function.

Intrathecal use: Monitor closely for signs and symptoms of overdose which may appear suddenly or insidiously, especially during the initial screening and dose-titration phase of treatment, and during reintroduction of therapy after a period of interruption. Signs/symptoms of overdose may include drowsiness, dizziness, somnolence, hypothermia, respiratory depression, seizures, rostral progression of hypotonia and loss of consciousness progressing to coma. If overdose is suspected, patient should be evaluated immediately in a hospital setting and the pump reservoir emptied.