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chlorzoxazone (klor-zox-a-zone)

EZE-DS, Paraflex, Parafon Forte DSC, Relaxazone, Remular, Remular-S, Strifon Forte DSC


Therapeutic: skeletal muscle relaxants (centrally acting)


Adjunct to rest and physical therapy in the treatment of muscle spasm associated with acute painful musculoskeletal conditions.


Skeletal muscle relaxation, most likely due to CNS depression. Therapeutic Effects: Skeletal muscle relaxation with decreased discomfort.

Adverse Reactions/Side Effects

CNS: dizziness, drowsiness. GI: GI BLEEDING, constipation, diarrhea, heartburn, nausea, vomiting. Derm: allergic dermatitis. Hemat: AGRANULOCYTOSIS, anemia. Misc: ALLERGIC REACTIONS, INCLUDING ANGIOEDEMA.



Examination and Evaluation

  • Monitor signs of allergic reactions and angioedema, including skin reactions, such as rash, itching, burning, welts, and swelling in the face, and pulmonary symptoms, such as tightness in the throat and chest, wheezing, cough, and dyspnea. Seek immediate medical assistance if these reactions occur.

  • Monitor signs of GI bleeding, including abdominal pain, vomiting blood, blood in stools, or black, tarry stools. Notify physician immediately if of these signs occur.

  • Be alert for signs of agranulocytosis (fever, sore throat, mucosal lesions, signs of infection, bruising) or unusual weakness and fatigue that might be due to anemia. Report these signs to the physician.

  • Assess patient's pain, stiffness, and ROM to help document antispasm effects.

  • Assess dizziness that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician, and caution the patient and family/caregivers to guard against falls and trauma.


  • Implement appropriate manual therapy techniques, physical agents, and therapeutic exercises to reduce pain and wean patient off muscle relaxants as soon as possible.

  • Help patient explore other nonpharmacologic methods to reduce chronic pain, such as relaxation techniques, exercise, counseling, and so forth.

  • Implement fall-prevention strategies, especially if balance is impaired (See Appendix E).

Patient/Client-Related Instruction

  • Advise patient and family or caregiver about the signs of allergic reactions, GI bleeding, and blood dyscrasias (see above under Examination and Evaluation), and to seek immediate medical assistance if these signs develop.

  • Inform patient that long-term use can cause tolerance and physical/psychologic dependence; encourage adherence to physical therapy so that drug therapy can be discontinued as soon as possible.

  • Inform patient that this drug may cause severe drowsiness, dizziness, and reduced psychomotor skills. Patients should avoid driving or other activities that require concentration and fast reactions.

  • Advise patient to avoid alcohol and other CNS depressants because of the increased risk of sedation and adverse effects.

  • Warn patient about anticholinergic effects such as dry mouth, constipation, urinary retention, sedation, and weakness; anticholinergic effects are often more severe in older adults.

  • Instruct patient and family/caregivers to report other troublesome side effects such as severe or prolonged ...

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