Muscle Relaxants/Muscle Pain

Question 1

What are side effects of muscle relaxants?

Answer 1

Sedation, dizziness, CNS depression

Question 2

Antispasmodics?

Answer 2

MOA: blocks nerves from signaling brain
Condition: spasms secondary to peripheral musculoskeletal conditions (Ex. injury, fatigue, and trauma)

Question 3

Antispastics?

Answer 3

MOA: blocks nerve signaling from the spinal cord - directly acts on skeletal muscle
Conditions: spasticity secondary to upper motor neuron lesions (Ex. MS, spinal cord injury, stroke, cerebral palsy, infection)

Question 4

Examples of antispasmodics?

Answer 4

Cyclobenzaprine and methocarbamol

Question 5

Examples of both antispasmodic and antispastic?

Answer 5

Diazepan and tizanidine

Question 6

Examples of antispastics

Answer 6

Baclofen

Question 7

What to know about carisoprodol (Soma)

Answer 7

Probably should not prescribe; Beer’s list, schedule IV; Causes euphoria and withdrawal/dependence

Question 8

Cyclobenzaprine

Answer 8

Acute musculoskeletal conditions only; AE - anticholinergic effects and arrythmias; on Beer’s list and structurally similar to TCAs (so do not use together)

Question 9

Methocarbamol

Answer 9

Acute painful musculoskeletal conditions; can discolor urine to brown/black/green; on Beer’s list

Question 10

Tizanidine

Answer 10

Manages spasticity; off label for acute pain; renal dosing; AE - hypotension; Structurally similar to clonidine, needs tapered off, CI with CYP1A2 inhibitors

Question 11

Diazepam

Answer 11

Spasticity; potential for dependence/abuse, withdrawal syndrome; On beer’s list, schedule IV

Question 12

Baclofen

Answer 12

Spasticity; renal dosing; withdrawal can occur; on Beer’s list if GFR<60; intrathecal pump available to treat spasticity

Question 13

What are the benefits of baclofen intrathecal pump

Answer 13

continuous delivery, fewer adverse effects, different rates throughout the day, can be removed if needed

Question 14

What are the cons of intrathecal baclofen pump

Answer 14

surgery, infection risk, potential leakage of spinal fluid, pump complications (withdrawal/overdose)

Question 15

Dantrolene

Answer 15

Spasticity; peripherally acting so lower side effects; discontinue in 45 days if not effective; BBW: hepatotoxicity

Question 16

When should glucocorticoids be used?

Answer 16

Reserved for severe flare-ups after muscle injury; short courses advised

Question 17

What are some limitations of muscle relaxants?

Answer 17

Overuse, potential for abuse and dependency, inappropriate long-term use

Question 18

Signs/symptoms of addiction and abuse?

Answer 18

1. Continuing to take after no longer needed
2. Dependent behaviors (feel unable to stop)
3. Mixing muscle relaxant with other drugs and/or alcohol

Question 19

What are the best muscle relaxant options for elderly?

Answer 19

Tizanidine, dantrolene, Baclofen if CrCl>60

Question 20

Which are the most sedating?

Answer 20

Tizanidine and Cyclobenzaprine

Question 21

Which are least sedating?

Answer 21

Methocarbamol and metaxalone