Nursing care
Baclofen: what to check before you give it
Written and reviewed by Dana Whitfield, RN, MSN · 4 min read · Updated September 2026
Short answer
Baclofen is a skeletal muscle relaxant used for spasticity from spinal cord injury or multiple sclerosis, given orally or by intrathecal pump. Abrupt withdrawal, especially from an intrathecal pump alarm or malfunction, causes high fever, severe rigidity, and rhabdomyolysis, and is a medical emergency requiring immediate intervention.
Why this drug and not another
Baclofen acts on GABA-B receptors in the spinal cord to inhibit reflex arcs, reducing the muscle spasticity seen in spinal cord injury, multiple sclerosis, and cerebral palsy. Unlike drugs that act peripherally on muscle fibre, baclofen works centrally, which allows it to reduce spasm frequency and severity without directly weakening voluntary muscle contraction to the same degree.
The intrathecal route delivers baclofen directly into the cerebrospinal fluid via an implanted pump, achieving therapeutic spinal cord concentrations at a fraction of the oral dose. This matters clinically because oral doses high enough to control severe spasticity often cause disabling sedation; intrathecal delivery bypasses that trade-off for patients who have failed oral therapy.
Administration and timing
Oral baclofen is usually started at a low dose and titrated upward over days to weeks, divided into three doses daily, to minimise sedation and dizziness while spasticity control is established. Doses are typically given with food to reduce GI upset.
Intrathecal baclofen is delivered by a surgically implanted, programmable pump refilled at scheduled clinic visits, usually every one to six months depending on dose and reservoir size. Nurses caring for a patient with an intrathecal pump must know the refill schedule and confirm it has not been missed, since a missed refill is one of the leading causes of sudden interruption in delivery.
Monitoring parameters
Monitor sedation level, respiratory rate, and blood pressure, since baclofen causes CNS depression that compounds with opioids, benzodiazepines, and alcohol. Track muscle tone and functional mobility to confirm the dose is achieving therapeutic spasticity reduction without excessive weakness that impairs transfers or ambulation.
For patients with an intrathecal pump, monitor for any pump alarm, and know that alarms indicating low reservoir volume, motor stall, or catheter occlusion require urgent evaluation, not routine follow-up. Baseline and periodic liver function tests are reasonable with oral therapy, since hepatotoxicity has been reported, though it is uncommon.
Adverse effects to report
Report excessive sedation, confusion, or respiratory depression, particularly in an older adult or one on other CNS depressants. Report new muscle weakness severe enough to affect safety, since the therapeutic window between reduced spasticity and functional weakness can be narrow.
The adverse effect that carries the highest stakes is intrathecal baclofen withdrawal. High fever, severe rebound spasticity or rigidity, altered mental status, and rhabdomyolysis signal that delivery has stopped, whether from pump failure, catheter dislodgement, or an empty reservoir. This progresses rapidly to multi-organ failure and death if untreated, and any pump alarm must be treated as a potential emergency until ruled out.
Contraindications and cautions
Use baclofen cautiously in renal impairment, since it is primarily renally excreted and accumulation increases toxicity risk. Caution also applies in patients with a seizure disorder, as baclofen can lower the seizure threshold, and in psychiatric conditions, since it has been associated with mood changes and, rarely, hallucinations on abrupt discontinuation.
Never discontinue baclofen abruptly by any route. Oral withdrawal causes rebound spasticity, hallucinations, and seizures. Intrathecal withdrawal is more severe and faster in onset because the spinal cord has adapted to continuous direct delivery, so any interruption removes that adaptation suddenly.
Teaching points the exam tests
The NCLEX-testable fact here is specific: intrathecal baclofen withdrawal presents with high fever, rigidity, and rhabdomyolysis, and a pump alarm is treated as an emergency, not a maintenance issue. Expect a question asking what a nurse should do first when an intrathecal pump alarms, with immediate assessment and prescriber notification as the answer, not waiting for the next scheduled refill.
Teach patients with an oral prescription never to stop the drug suddenly and to taper only under medical supervision. Teach patients with an implanted pump to recognise early withdrawal signs, itching, increased spasticity, and to seek emergency care immediately if the pump alarms or symptoms appear, since early treatment prevents progression to rhabdomyolysis and organ failure.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our neurological practice questions are the closest set to what this page covers.
Common questions
What happens if an intrathecal baclofen pump fails?
Delivery stops abruptly, and the spinal cord loses the continuous GABA-B stimulation it had adapted to. This causes high fever, severe rigidity, altered mental status, and rhabdomyolysis, a withdrawal syndrome that can progress to multi-organ failure if not treated immediately.
Is a baclofen pump alarm an emergency?
Yes. Any alarm indicating low reservoir, motor stall, or catheter occlusion must be evaluated urgently, since it signals a possible interruption in drug delivery. Treat it the same way you would treat any sign of acute withdrawal until it is ruled out.
Can baclofen be stopped suddenly?
No, by either route. Oral baclofen causes rebound spasticity, hallucinations, and seizures if stopped abruptly. Intrathecal baclofen withdrawal is more severe and faster, producing high fever, rigidity, and rhabdomyolysis.
Why is baclofen given intrathecally instead of orally?
Intrathecal delivery places the drug directly into the cerebrospinal fluid, achieving spinal cord concentrations effective for severe spasticity at doses far lower than oral therapy would require. This avoids the disabling sedation that high oral doses cause.