Tizanidine

What is Tizanidine

Tizanidine is an oral agent used to reduce muscle tone associated with spasticity related to cerebral or spinal cord injury, multiple sclerosis, or other spastic disorders.

The imidazoline chemical structure of tizanidine is related to that of clonidine and other central-acting alpha₂-adrenergic agonists.

Tizanidine significantly reduces muscle tone and frequency of spasms in patients with spasticity due to spinal cord injury; but does not reduce muscle strength.

Both tizanidine and baclofen (see separate monograph) inhibit spinal interneuron firing, however, tizanidine’s effects are mediated by alpha₂-receptors whereas baclofen acts directly on neuronal membrane polarization.

The efficacy of tizanidine in the treatment of spasticity is comparable to baclofen.

Tizanidine produces more drowsiness and sedation than baclofen, but tizanidine is not associated with the muscle weakness which may occur with baclofen therapy.

Tizanidine was approved by the FDA on December 3, 1996.

Brand Name

Zanaflex

Indications

1. multiple sclerosis
2. spasticity
3. spinal cord injury

For the acute and intermittent management of increased muscle tone associated with spasticity (including spasticity related to multiple sclerosis or spinal cord injury)

Side Effects

1. anaphylactoid reactions
2. anemia
3. angioedema
4. arthralgia
5. asthenia
6. blurred vision
7. bradycardia
8. constipation
9. cystitis
10. depression
11. dizziness
12. drowsiness
13. dyskinesia
14. elevated hepatic enzymes
15. excitability
16. exfoliative dermatitis
17. fatigue
18. hallucinations
19. hepatic failure
20. hepatic necrosis
21. hepatitis
22. hypercholesterolemia
23. hyperlipidemia
24. hypotension
25. increased urinary frequency
26. infection
27. influenza
28. jaundice
29. leukocytosis
30. leukopenia
31. paresthesias
32. pharyngitis
33. QT prolongation
34. rash
35. rhinitis
36. Stevens-Johnson syndrome
37. syncope
38. thrombocytopenia
39. tremor
40. vomiting
41. weakness
42. withdrawal
43. xerostomia

Monitoring Parameters

• LFTs

Contraindications

• abrupt discontinuation
• breast-feeding
• driving or operating machinery
• geriatric
• hepatic disease
• hypotension
• labor
• obstetric delivery
• pregnancy
• psychosis
• renal failure
• renal impairment

Interactions

• Acebutolol
• Acetaminophen
• Acetaminophen; Aspirin, ASA; Caffeine
• Acetaminophen; Butalbital
• Acetaminophen; Butalbital; Caffeine
• Acetaminophen; Butalbital; Caffeine; Codeine
• Acetaminophen; Caffeine
• Acetaminophen; Caffeine; Dihydrocodeine
• Acetaminophen; Caffeine; Magnesium Salicylate; Phenyltoloxamine
• Acetaminophen; Caffeine; Phenyltoloxamine; Salicylamide
• Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine
• Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine
• Acetaminophen; Chlorpheniramine; Phenylephrine; Phenyltoloxamine
• Acetaminophen; Codeine
• Acetaminophen; Dextromethorphan
• Acetaminophen; Dextromethorphan; Doxylamine
• Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine
• Acetaminophen; Dextromethorphan; Phenylephrine
• Acetaminophen; Dextromethorphan; Pseudoephedrine
• Acetaminophen; Dichloralphenazone; Isometheptene
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