Medscape is available in 5 Language Editions – Choose your Edition here.


Radiation-Induced Lumbosacral Plexopathy Medication

  • Author: Rajesh R Yadav, MD; Chief Editor: Robert H Meier, III, MD  more...
Updated: Aug 02, 2015

Medication Summary

Tricyclic antidepressants (TCAs), such as amitriptyline, may be used in lower doses. The use of antiepileptics may be helpful.


Tricyclic antidepressants

Class Summary

TCAs have central and peripheral anticholinergic effects, as well as sedative effects, and block the active reuptake of norepinephrine and serotonin. The multifactorial mechanism of analgesia may include improved sleep, an altered perception of pain, and an increase in pain threshold. The efficacy of these drugs can be potentiated with the concomitant use of opiates and nonsteroidal anti-inflammatory drugs (NSAIDs). Rarely should these drugs be used in the treatment of acute pain, since a few weeks may be required for them to become effective.

Amitriptyline (Elavil)


Analgesic for certain chronic and neuropathic pain. Amitriptyline has the most anticholinergic side effects of all drugs in this category.


Antiepileptic drugs

Class Summary

These drugs stabilize neuronal membranes and reduce neuronal hyperexcitability. The analgesic effect may be due to such stabilization and control of hyperexcitability, because aberrant electrical activity has been recorded with neuropathic pain.

Gabapentin (Neurontin)


Has anticonvulsant properties and antineuralgic effects; however, the exact mechanism of action is unknown. Gabapentin is structurally related to GABA but does not interact with GABA receptors.

Carbamazepine (Tegretol)


Used typically for generalized tonic-clonic seizures and partial seizures, as well as for trigeminal neuralgia. Plasma levels are between 4-12 mcg/mL for analgesic and antiseizure response.

Valproic acid (Depakene)


Generally indicated for absence seizures and generalized tonic-clonic seizures. Some relief may be noted with neuropathic pain, especially the lancinating type.



Class Summary

Glucocorticoids have anti-inflammatory, hormonal, and metabolic effects. Inflammation is suppressed with the blockage of phospholipase A2, which inhibits the formation of arachidonic acid and, thus, the prostaglandins. The analgesic effect may be due to the anti-inflammatory activity, with a decrease in edema.

Dexamethasone (Decadron, AK-Dex)


For various allergic and inflammatory diseases. Dexamethasone decreases inflammation by suppressing the migration of polymorphonuclear leukocytes and by reducing capillary permeability.



Class Summary

These drugs are generally used for short-term, acute pain that is moderate to severe in nature, as well as for chronic pain (eg, cancer). They provide analgesia without antipyretic or anti-inflammatory action. The mechanism of action is the inhibition of nociceptive impulses at the dorsal horn of the spinal cord and at supraspinal sites due to interaction with opiate receptors. Structural derivatives of GABA are also used in the management of neuropathic pain.

Pregabalin (Lyrica)


Structural derivative of GABA. Pregabalin's mechanism of action is unknown. This agent binds with high affinity to the alpha2 -delta site (a calcium channel subunit). In vitro, pregabalin reduces the calcium-dependent release of several neurotransmitters, possibly by modulating calcium channel function. It is FDA approved for neuropathic pain associated with diabetic peripheral neuropathy or postherpetic neuralgia and as an adjunctive therapy in partial-onset seizures.

Methadone (Dolophine)


Used in the management of severe pain. Methadone inhibits ascending pain pathways, diminishing the perception of and response to pain.

Morphine sulfate (Duramorph, MS Contin, Astramorph)


Available in immediate (3-4 h duration) and extended release preparation (12 h). Switch over to long-acting preparations (MS Contin) once pain is controlled with short-acting preparation (MS IR). Morphine can produce drug dependence and has the potential for being abused. Tolerance may develop with repeated exposure. Abrupt cessation or sudden reduction in dose with prolonged use may result in withdrawal symptoms. Physical dependence is not of paramount importance in terminally ill patients.

Contributor Information and Disclosures

Rajesh R Yadav, MD Associate Professor, Section of Physical Medicine and Rehabilitation, MD Anderson Cancer Center, University of Texas Medical School at Houston

Rajesh R Yadav, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Michael T Andary, MD, MS Professor, Residency Program Director, Department of Physical Medicine and Rehabilitation, Michigan State University College of Osteopathic Medicine

Michael T Andary, MD, MS is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, American Medical Association, Association of Academic Physiatrists

Disclosure: Received honoraria from Allergan for speaking and teaching.

Chief Editor

Robert H Meier, III, MD Director, Amputee Services of America; Active Medical Staff, Presbyterian/St Luke’s Hospital, Spalding Rehabilitation Hospital, Select Specialty Hospital; Consulting Staff, Kindred Hospital

Robert H Meier, III, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, Association of Academic Physiatrists

Disclosure: Nothing to disclose.

  1. Pettigrew LC, Glass JP, Maor M, et al. Diagnosis and treatment of lumbosacral plexopathies in patients with cancer. Arch Neurol. 1984 Dec. 41(12):1282-5. [Medline].

  2. Klimek M, Kosobucki R, Luczynska E, Bieda T, Urbanski K. Radiotherapy-induced lumbosacral plexopathy in a patient with cervical cancer: a case report and literature review. Contemp Oncol (Pozn). 2012. 16(2):194-6. [Medline]. [Full Text].

  3. Yi SK, Mak W, Yang CC, Liu T, Cui J, Chen AM, et al. Development of a standardized method for contouring the lumbosacral plexus: a preliminary dosimetric analysis of this organ at risk among 15 patients treated with intensity-modulated radiotherapy for lower gastrointestinal cancers and the incidence of radiation-induced lumbosacral plexopathy. Int J Radiat Oncol Biol Phys. 2012 Oct 1. 84(2):376-82. [Medline].

  4. Ashenhurst EM, Quartey GR, Starreveld A. Lumbo-sacral radiculopathy induced by radiation. Can J Neurol Sci. 1977 Nov. 4(4):259-63. [Medline].

  5. Jaeckle KA, Young DF, Foley KM. The natural history of lumbosacral plexopathy in cancer. Neurology. 1985 Jan. 35(1):8-15. [Medline].

  6. Abu-Rustum NR, Rajbhandari D, Glusman S, et al. Acute lower extremity paralysis following radiation therapy for cervical cancer. Gynecol Oncol. 1999 Oct. 75(1):152-4. [Medline].

  7. Iglicki F, Coffin B, Ille O, et al. Fecal incontinence after pelvic radiotherapy: evidences for a lumbosacral plexopathy. Report of a case. Dis Colon Rectum. 1996 Apr. 39(4):465-7. [Medline].

  8. Jaeckle KA. Neurological manifestations of neoplastic and radiation-induced plexopathies. Semin Neurol. 2004 Dec. 24(4):385-93. [Medline].

  9. Jaeckle KA. Neurologic manifestations of neoplastic and radiation-induced plexopathies. Semin Neurol. 2010 Jul. 30(3):254-62. [Medline].

  10. Ozkavukcu E, Cayli E, Yagci C, et al. Ruptured iliac aneurysm presenting as lumbosacral plexopathy. Diagn Interv Radiol. 2008 Mar. 14(1):26-8. [Medline]. [Full Text].

  11. Abdellaoui A, West NJ, Tomlinson MA, et al. Lower limb paralysis from ischaemic neuropathy of the lumbosacral plexus following aorto-iliac procedures. Interact Cardiovasc Thorac Surg. 2007 Aug. 6(4):501-2. [Medline]. [Full Text].

  12. Moskovic E, Curtis S, A'Hern RP, et al. The role of diagnostic CT scanning of the brachial plexus and axilla in the follow-up of patients with breast cancer. Clin Oncol (R Coll Radiol). 1992 Mar. 4(2):74-7. [Medline].

  13. Taylor BV, Kimmel DW, Krecke KN. Magnetic resonance imaging in cancer-related lumbosacral plexopathy. Mayo Clin Proc. 1997 Sep. 72(9):823-9. [Medline].

  14. Wilbourn AJ. Electrodiagnosis of plexopathies. Neurol Clin. 1985 Aug. 3(3):511-29. [Medline].

  15. Masakado Y, Kawakami M, Suzuki K, et al. Clinical neurophysiology in the diagnosis of peroneal nerve palsy. Keio J Med. 2008 Jun. 57(2):84-9. [Medline].

  16. Pritchard J, Anand P, Broome J, et al. Double-blind randomized phase II study of hyperbaric oxygen in patients with radiation-induced brachial plexopathy. Radiother Oncol. 2001 Mar. 58(3):279-86. [Medline].

  17. Tunio M, Al Asiri M, Bayoumi Y, et al. Lumbosacral plexus delineation, dose distribution, and its correlation with radiation-induced lumbosacral plexopathy in cervical cancer patients. Onco Targets Ther. 2015. 8:21-7. [Medline].

  18. Enevoldson TP, Scadding JW, Rustin GJ, et al. Spontaneous resolution of a postirradiation lumbosacral plexopathy. Neurology. 1992 Nov. 42(11):2224-5. [Medline].

  19. Bradley WG, Fewings JD, Cumming WJ, et al. Delayed myeloradiculopathy produced by spinal X-irradiation in the rat. J Neurol Sci. 1977 Jan-Feb. 31(1):63-82. [Medline].

  20. Cavanagh JB. Prior x-irradiation and the cellular response to nerve crush: duration of effect. Exp Neurol. 1968 Oct. 22(2):253-8. [Medline].

  21. Dahele M, Davey P, Reingold S, et al. Radiation-induced lumbo-sacral plexopathy (RILSP): an important enigma. Clin Oncol (R Coll Radiol). 2006 Jun. 18(5):427-8. [Medline].

  22. Glantz MJ, Burger PC, Friedman AH. Treatment of radiation-induced nervous system injury with heparin and warfarin. Neurology. 1994 Nov. 44(11):2020-7. [Medline].

  23. Stryker JA, Sommerville K, Perez R, et al. Sacral plexus injury after radiotherapy for carcinoma of cervix. Cancer. 1990 Oct 1. 66(7):1488-92. [Medline].

  24. Stubgen JP. Neuromuscular disorders in systemic malignancy and its treatment. Muscle Nerve. 1995 Jun. 18(6):636-48. [Medline].

  25. Thomas JE, Cascino TL, Earle JD. Differential diagnosis between radiation and tumor plexopathy of the pelvis. Neurology. 1985 Jan. 35(1):1-7. [Medline].

All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.