Skip to Content

Lioresal Side Effects

Generic Name: baclofen

Note: This page contains information about the side effects of baclofen. Some of the dosage forms included on this document may not apply to the brand name Lioresal.

For the Consumer

Applies to baclofen: oral tablet

In addition to its needed effects, some unwanted effects may be caused by baclofen (the active ingredient contained in Lioresal). In the event that any of these side effects do occur, they may require medical attention.

If any of the following side effects occur while taking baclofen, check with your doctor or nurse as soon as possible:

Less common or rare
  • Bloody or dark urine
  • chest pain
  • fainting
  • hallucinations (seeing or hearing things that are not there)
  • mental depression or other mood changes
  • ringing or buzzing in the ears
  • skin rash or itching
Symptoms of overdose
  • Blurred or double vision
  • convulsions (seizures)
  • muscle weakness (severe)
  • shortness of breath or unusually slow or troubled breathing
  • vomiting

Some of the side effects that can occur with baclofen may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Confusion
  • dizziness or lightheadedness
  • drowsiness
  • nausea
  • unusual weakness, especially muscle weakness
Less common or rare
  • Abdominal or stomach pain or discomfort
  • clumsiness, unsteadiness, trembling, or other problems with muscle control
  • constipation
  • diarrhea
  • difficult or painful urination or decrease in amount of urine
  • false sense of well-being
  • frequent urge to urinate or uncontrolled urination
  • headache
  • loss of appetite
  • low blood pressure
  • muscle or joint pain
  • numbness or tingling in hands or feet
  • pounding heartbeat
  • sexual problems in males
  • slurred speech or other speech problems
  • stuffy nose
  • swelling of ankles
  • trouble in sleeping
  • unexplained muscle stiffness
  • unusual excitement
  • unusual tiredness
  • weight gain

After you stop taking this drug, it is possible that you may still experience side effects that need medical attention. If you notice any of the following side effects check with your doctor immediately:

  • Convulsions (seizures)
  • hallucinations (seeing or hearing things that are not there)
  • increase in muscle spasm, cramping, or tightness
  • mood or mental changes
  • unusual nervousness or restlessness

For Healthcare Professionals

Applies to baclofen: compounding powder, intrathecal solution, oral tablet

Nervous system

Nervous system side effects have been common. They have included transient drowsiness and sedation in as many as 63% of treated patients. Dizziness, weakness, and fatigue have been reported commonly. Akathisia, ataxia, opisthotonos, nystagmus, somnolence, dystonia, and decreased reflexes have also been reported. At high doses, coma and respiratory depression may occur. Dystonia, dyskinesia, chorea, encephalopathy, seizures (including generalized nonconvulsive status epilepticus), catatonia, and frontal lobe syndrome have been reported rarely. A case of recurrent transient global amnesia has also been reported.

Most of the side effects listed above were reported following intrathecal injection of baclofen (the active ingredient contained in Lioresal) In addition, patients receiving intrathecal baclofen may be at risk for baclofen toxicity or withdrawal due to pump/catheter malfunction, patient position (facilitating rostral spread) and other factors.[Ref]


In the first 9 years of postmarketing experience, 27 cases of withdrawal temporally related to the cessation of baclofen (the active ingredient contained in Lioresal) therapy were reported. Six of the patients died. In most cases, symptoms of withdrawal appeared within hours to a few days following interruption of baclofen therapy. Common reasons for abrupt interruption of intrathecal baclofen therapy included malfunction of the catheter (especially disconnection), low volume in the pump reservoir, and end of pump battery life. Human error may have also played a causal or contributing role in some cases.

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.

All patients receiving intrathecal baclofen therapy are potentially at risk for withdrawal. Early symptoms of baclofen withdrawal may include return of baseline spasticity, pruritus, hypotension, and paresthesias. Some clinical characteristics of 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.

Rapid, accurate diagnosis and treatment in an emergency room or intensive care setting are important in order to prevent the potentially life-threatening central nervous system and systemic effects of intrathecal baclofen withdrawal.

The suggested treatment for intrathecal baclofen withdrawal is the restoration of intrathecal baclofen at or near the same dosage as before therapy was interrupted. However, if restoration of intrathecal delivery is delayed, treatment with GABA-ergic agonist drugs such as oral or enteral baclofen, or oral, enteral, or intravenous benzodiazepines may prevent potentially fatal sequelae. Oral or enteral baclofen alone should not be relied upon to halt the progression of intrathecal baclofen withdrawal.

Seizures have been reported during overdose and with withdrawal from baclofen intrathecal as well as in patients maintained on therapeutic doses of baclofen intrathecal.[Ref]

Abrupt withdrawal of intrathecal baclofen (regardless of the cause) has resulted in sequelae that includes high fever, altered mental status, exaggerated rebound spasticity, and muscle rigidity that in rare cases progressed to rhabdomyolysis, multiple organ system failure, and death. Sudden discontinuation of baclofen may result in neuropsychiatric signs and symptoms of withdrawal including confusion, seizures, psychosis, hallucinations, disorientation, dyskinesia, and visual disturbances.

A case has been reported of a febrile reaction to subarachnoid baclofen administration.

Cases of intrathecal mass at the tip of the implanted catheter have been reported, most of them involving pharmacy compounded analgesic admixtures.[Ref]


One small study has reported, however, that the frequency of depression and anxiety in baclofen-treated patients is not different from patients not taking baclofen (the active ingredient contained in Lioresal) [Ref]

Psychiatric side effects have been reported including paranoia, mania, euphoria, depression, anxiety, psychosis, hallucinations, paresthesias, hysteria, and personality disorder.[Ref]


Cardiovascular side effects including hypertension, bradycardia, and orthostatic hypotension have been reported.[Ref]


Gastrointestinal side effects including nausea, vomiting, constipation, abdominal pain, diarrhea, dysphagia, fecal incontinence, gastrointestinal hemorrhage, and tongue disorder have been reported (especially with rapid dose increases).[Ref]


Genitourinary side effects including urinary frequency have been reported in 2% to 6% of treated patients. Enuresis, urinary retention, dysuria, abnormal ejaculation, kidney calculus, oliguria, vaginitis and impotence have also been reported.[Ref]


Endocrine side effects including ovarian cysts have been palpable in 4% of women treated with baclofen (the active ingredient contained in Lioresal) for up to one year.[Ref]


Respiratory side effects including apnea, dyspnea, and hyperventilation have been reported. Cases of acute bronchospasm (particularly in patients with asthma) have been reported rarely.[Ref]


Hepatic side effects including elevated liver function tests have been reported rarely.[Ref]


Dermatologic side effects including rash, sweating, alopecia, contact dermatitis, and skin ulcer have been reported.[Ref]


Hematologic side effects including leukocytosis and petechial rash have been reported.[Ref]


Other effects including fever, malaise, hypothermia, slurred speech, nightmares, confusion, headache, memory impairment, insomnia, and excitement have been reported.[Ref]


Oncologic side effects including carcinoma have been reported.[Ref]


Musculoskeletal side effects including ataxia and muscle pain have been reported.[Ref]


General side effects have included effects on sleep. One study has reported that a single, therapeutic dose of baclofen (the active ingredient contained in Lioresal) alters sleep architecture and produces a small reduction in mean sleep oxygen saturation, but does not significantly increase sleep disordered breathing.[Ref]


1. Grande LA, Loeser JD, Samii A "Recurrent transient global amnesia with intrathecal baclofen." Anesth Analg 106 (2008): 1284-7, table of contents

2. Silbert PL, Stewart-Wynne EG "Increased dystonia after intrathecal baclofen." Neurology 42 (1992): 1639-40

3. Wolf ME, Almy G, Toll M, Mosnaim AD "Mania associated with the use of baclofen." Biol Psychiatry 17 (1982): 757-9

4. Zak R, Solomon G, Petito F, Labar D "Baclofen-induced generalized nonconvulsive status epilepticus." Ann Neurol 36 (1994): 113-4

5. Rush JM, Gibberd FB "Baclofen-induced epilepsy." J R Soc Med 83 (1990): 115-6

6. Jamous A, Kennedy P, Psychol C, Grey N "Psychological and emotional effects of the use of oral baclofen - a preliminary study." Paraplegia 32 (1994): 349-53

7. Crystal HA "Baclofen therapy may be associated with chorea in Alzheimer's disease." Ann Neurol 28 (1990): 839

8. Hormes JT, Benarroch EE, Rodriguez M, Klass DW "Periodic sharp waves in baclofen-induced encephalopathy." Arch Neurol 45 (1988): 814-5

9. "Product Information. Lioresal Intrathecal (baclofen)." Medtronic Inc, Minneapolis, MN.

10. Sandyk R "Orofacial dyskinesia induced by baclofen in a patient with hypothyroidism." Clin Pharm 5 (1986): 109

11. Abarbanel J, Herishanu Y, Frisher S "Encephalopathy associated with baclofen." Ann Neurol 17 (1985): 617-8

12. Romijn JA, van Lieshout JJ, Velis DN "Reversible coma due to intrathecal baclofen." Lancet 2 (1986): 696

13. Ryan DM, Blumenthal FS "Baclofen-induced dyskinesia." Arch Phys Med Rehabil 74 (1993): 766-7

14. Pauker SL, Brown R "Baclofen-induced catatonia." J Clin Psychopharmacol 6 (1986): 387-8

15. "Product Information. Lioresal (baclofen)." Medtronic Inc, Minneapolis, MN.

16. Gomar C, Carrero EJ "Delayed arousal after general anesthesia associated with baclofen." Anesthesiology 81 (1994): 1306-7

17. Liu HC, Tsai SC, Liu TY, Chi CW "Baclofen-induced frontal lobe syndrome: case report." Paraplegia 29 (1991): 554-6

18. Delhaas EM, Brouwers JR "Intrathecal baclofen overdose: report of 7 events in 5 patients and review of the literature." Int J Clin Pharmacol Ther Toxicol 29 (1991): 274-80

19. Penn RD "Intrathecal baclofen for spasticity of spinal origin: seven years of experience." J Neurosurg 77 (1992): 236-40

20. Barker I, Grant IS "Convulsions after abrupt withdrawal of baclofen." Lancet 2 (1982): 556-7

21. Kirubakaran V, Mayfield D, Rengachary S "Dyskinesia and psychosis in a patient following baclofen withdrawal." Am J Psychiatry 141 (1984): 692-3

22. Terrence CF, Fromm GH "Complications of baclofen withdrawal." Arch Neurol 38 (1981): 588-9

23. Lees AJ, Clarke CR, Harrison MJ "Hallucinations after sudden withdrawal of baclofen." Lancet 2 (1977): 44-5

24. Kofler M, Arturo Leis A "Prolonged seizure activity after baclofen withdrawal." Neurology 42 (1992): 697-8

25. Yassa RY, Iskandar HL "Baclofen-induced psychosis: two cases and a review." J Clin Psychiatry 49 (1988): 318-20

26. Arnold ES, Rudd SM, Kirshner H "Manic psychosis following rapid withdrawal from baclofen." Am J Psychiatry 137 (1980): 1466-7

27. Garabedian-Ruffalo SM, Ruffalo RL "Adverse effects secondary to baclofen withdrawal." Drug Intell Clin Pharm 19 (1985): 304-6

28. Rivas DA, Chancellor MB, Hill K, Freedman MK "Neurological manifestations of baclofen withdrawal." J Urol 150 (1993): 1903-5

29. Siegfried RN, Jacobson L, Chabal C "Development of an acute withdrawal syndrome following the cessation of intrathecal baclofen in a patient with spasticity." Anesthesiology 77 (1992): 1048-50

30. Wu SS, Dolan KA, Michael Ferrante F "Febrile reaction to subarachnoid baclofen administration." Anesthesiology 96 (2002): 1270-2

31. Stewart JT "A case of mania associated with high-dose baclofen therapy." J Clin Psychopharmacol 12 (1992): 215-7

32. Sommer BR, Petrides G "A case of baclofen-induced psychotic depression." J Clin Psychiatry 53 (1992): 211-2

33. Sandyk R, Gillman MA "Baclofen-induced memory impairment." Clin Neuropharmacol 8 (1985): 294-5

34. Roberge RJ, Martin TG, Hodgman M, Benitez JG, Brunswick JE "Supraventricular tachyarrhythmia associated with baclofen overdose." J Toxicol Clin Toxicol 32 (1994): 291-7

35. "Multum Information Services, Inc. Expert Review Panel"

36. White WB "Aggravated CNS depression with urinary retention secondary to baclofen administration." Arch Intern Med 145 (1985): 1717-8

37. Dicpinigaitis PV, Nierman DM, Miller A "Baclofen-induced bronchoconstriction." Ann Pharmacother 27 (1993): 883-4

38. Chui LK, Pelot D "Hepatic enzyme elevations associated with baclofen." Clin Pharm 3 (1984): 196-7

39. Lynde CW, McLean DI, Bachand R, Paty D "Morbilliform rash secondary to baclofen ingestion." Ann Neurol 13 (1983): 216

40. Finnimore AJ, Roebuck M, Sajkov D, Mcevoy RD "The effects of the GABA agonist, baclofen, on sleep and breathing." Eur Respir J 8 (1995): 230-4

Not all side effects for Lioresal may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.