Parenteral Manual


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Alternate Name(s): 
Muscle relaxant, antispastic
Original Date: 
August 2005
  • Severe spasticity unresponsive to oral baclofen or unacceptable side effects
  • Alternative to ablative neurosurgical procedures
  • Restricted to Neurosurgery
Reconstitution and Stability: 
  • Each ampoule intended for single use as 1 mL ampoule (0.05 mg/mL) for screening, 20 mL ampoule (0.5 mg/mL) for infusion, and 5 mL ampoule (2 mg/mL) for reservoir
  • Use intrathecal immediately
  • May dilute in normal saline without preservative
  • Stable for chronic use in SynchroMed Infusion System for 11 weeks and Infusaid pump for 28 days

- Solutions Compatible: NS

- Additives/Above Cassette Compatible: morphine

- Y-site Compatible: no information

Incompatible: dextrose, do not mix with other drugs


(For approved routes of administration by nursing personnel, refer to Policy for the Administration of Intravenous Medications.)

IV Direct NO
IV Intermittent Infusion NO
IV Continuous Infusion NO

YES, only adminstered by physician by direct injection or infusion
TEST DOSE     Usual dilution: 50 mcg/mL
                      Infusion Time: > 1 minute

MAINTENANCE infusion     Usual dilution: 500-2000 mcg/mL
                             Infusion time: titrate to patient's needs


(For neonatal dosages, refer to Neonatal IV Drug Manual.)


  • Screening dose: 50 mcg for 1 dose and observe for 4-8 hours; very small children may receive 25 mcg; if ineffective, a repeat dosage increased by 50% (eg. 75 mcg) may be repeated in 24 hours; if suboptimal, a third dose of 100 mcg may be repeated in 24 hours
  • Maintenance dose:   
    - Continuous Infusion: Initial
        if screening dose duration >8 hours: Daily dose = effective screening dose
        if screening dose duration <8 hours: Daily dose = twice effective screening dose
  • Continuous infusion dose mcg/hour = daily dose divided by 24 hours
  • Average daily dose:   
    - Children < 12 years: 100-300 mcg/day (4.2-12.5 mcg/hour);
      doses as high as 1000 mcg/day have been used
    -Children > 12 years and Adults: 300-800 mcg/day (12.5-33 mcg/hour);
      doses as high as 2000 mcg/day have been used.
Potential hazards of parenteral administration: 
  • Cardiovascular collapse
  • CNS depression (life-threatening)
  • Respiratory failure
  • Other adverse effects include: hypotension, chest pain, palpitations, drowsiness, fatigue, vertigo, dizziness, psychiatric disturbances, insomnia, slurred speech, headache, hypotonia, ataxia, rash, pruritis, nausea, constipation, anorexia, dysgeusia, diarrhea, abdominal pain, xerostomia, impotence, urinary frequency, nocturia, hematuria, dyspnea, diaphoresis
  • Resuscitative equipment should be available during screening trial
  • Increased CNS depression when administered with other CNS depressants
  • May decrease lithium's effect
  • Use with caution in patients with seizure disorder, impaired renal function, peptic ulcer disease, stroke, ovarian cysts, psychotic disorders, autonomic dysreflexia
  • Monitor muscle rigidity, spasticity (decrease in number and severity of spasms)

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