Therapeutic: antispasticity agents (centrally acting)
Increased muscle tone associated with spasticity due to multiple sclerosis or spinal cord injury.
Acts as an agonist at central alpha-adrenergic receptor sites. Reduces spasticity by ↑ presynaptic inhibition of motor neurons. Therapeutic Effects: ↓ spasticity, allowing better function.
Adverse Reactions/Side Effects
CNS: anxiety, depression, dizziness, sedation, weakness, dyskinesia, hallucinations, nervousness. EENT: blurred vision, pharyngitis, rhinitis. CV: hypotension, bradycardia. GI: abdominal pain, diarrhea, dry mouth, dyspepsia, constipation, hepatocellular injury, increased liver enzymes, vomiting. GU: urinary frequency. Derm: rash, skin ulcers, sweating. MS: back pain, myasthenia, paresthesia. Misc: fever, speech disorder.
PHYSICAL THERAPY IMPLICATIONS
Examination and Evaluation
Assess patient's spasticity, ROM, functional ability, and posture (e.g., head control and trunk stability), especially when beginning tizanidine treatment or during dose adjustments. Communicate with physician, family/caregivers, and other health professionals to determine if dosage is helping achieve desired functional outcomes.
Be alert for symptoms such as back pain, muscle weakness, paresthesia, or dyskinesia. Differentiate whether these symptoms are caused by neuromuscular pathology versus drug induced.
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.
Monitor CNS symptoms such as anxiety, nervousness, depression, sedation, speech problems, and hallucinations. Report these problems; excessive or prolonged CNS symptoms may require a reduction in dose.
Assess blood pressure periodically and compare to normal values (See Appendix F). Report low blood pressure (hypotension), especially if patient experiences dizziness, fatigue, or other symptoms.
Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report slow heart rate (bradycardia) or symptoms of other arrhythmias, including palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.
Implement aggressive therapeutic exercises (neuromuscular reeducation, postural stabilization, gait training, other task-specific training) to help patient adjust to reduced spasticity and tone.
Because of the risk of hypotension and bradycardia, use caution during aerobic exercise and other forms of therapeutic exercise. Assess exercise tolerance frequently (blood pressure, heart rate, fatigue levels), and terminate exercise immediately if any untoward responses occur (See Appendix L).
Guard against falls and trauma due to sedation, dizziness, or abnormally low tone in the trunk and lower extremities. Implement fall prevention strategies, especially if patient exhibits excessive sedation, dizziness, or other impairments that affect gait and balance (See Appendix E).
To minimize orthostatic hypotension, patient should move slowly when assuming a more upright position.