Drugs Used to Treat Chronic Pain (Muscle Relaxants)

Question 1

Zanaflex (Tizanidine)

Answer 1

Class: Muscle Relaxant

Mechanism of action:
-α2 receptor agonist that inhibits the release of norepinephrine (inverse agonist); blocks sympathetic mediated pain

Indication:
-Relief of acute painful muscle conditions of local origin

Pharmacological effects:
-Metabolized in the liver; baseline liver enzyme levels needed before beginning and during treatment

How this drug might effect dental treatment of patient
oAdverse effects you have to consider:
-Dry mouth
-Somnolence (drowsiness)
-Dizziness
-Orthostatic hypotension
-Can lower HR and BP (vital signs monitored during therapy)

oContraindicated drugs:
-CNS depressants

oContraindications:

oWhich analgesic can the patient take:

Question 2

Flexeril (Cyclobenzaprine)

Answer 2

Class: Muscle Relaxant

Mechanism of action:
-Unknown; may be related to tricyclic antidepressant-like structure

Indication:
-Muscle relaxation related to antidepressant effects or to normalization of quality of sleep

Pharmacological effects:

How this drug might effect dental treatment of patient
oAdverse effects you have to consider:
-Tachycardia

oContraindicated drugs:
-CNS depressants

oContraindications:

• Heart disease
• Elderly patients

oWhich analgesic can the patient take:

Question 3

Skelaxin (Metaxalone)

Answer 3

Class: Muscle Relaxant

Mechanism of action:

• Not sure how it works
• Works in medulla

Indication:

Pharmacological effects:
-Anticholinergic and analgesic effects; may not have direct muscle relaxing effects

How this drug might effect dental treatment of patient
oAdverse effects you have to consider:
-Drowsiness
-Sedation

oContraindicated drugs:
-CNS depressants

oContraindications:

• Glaucoma
• Myasthenia gravis
• Ulcer
• Angina

oWhich analgesic can the patient take:

Question 4

Summary of Muscle Relaxants

Answer 4

• Anti-depressant and sedative properties related to pain relief
• Mechanisms are not clearly related to muscle relaxation
• All are CNS depressants and can interact with other CNS depressants