T3 Komiskey - Centrally Acting Antispasmotics

Front 1

define muscle spasm and relate it to pain.

Back 1

an involuntary tension that occurs where the person is unable to completely relax the muscle; this spasm creates pain impulses from the muscle to the CNS (it is a cycle where increases in pain=increases in spasm)

Front 2

what are some causes of spasm?

Back 2

excessive usage and local injury, over medication (anti-psychotics), epilepsy, hypocalcemia, and neurologic disorders (MS, PD)

Front 3

spasms may present with inflammaiton, edema, pain, loss of coordination and reduced mobility. what types of drugs/therapies are used to treat spasms?

Back 3

antispasmotics; combinations of analgesics, anti-inflammatory agents and centrally acting skeletal muscle relaxants and rehab (immobilization, hydrotherapy, ultrasound, exercise, massages, and maniupulation)

Front 4

Name specific skeletal muscle relaxants (and their MOAs) used to treat spasticity.

Back 4

Baclofen (GABAb agonist) inhibits transmission at spinal level and depresses the CNS; diazepam (GABAa agonist; sedation is a problem); tizanidine (alpha 2 adrenoreceptor agonist indicated for spasticity associated with MS or spinal cord injury; centrally acting muscle relaxant); clonidine (centrally acting alpha-2 agent that activates inhibitory neurons that reduce sympathetic outflow which decreases vasomotor tone and heart rate; DANTROLENE: acts directly on skeletal muscle and produces few central A/es making it the drug of choice (increase dose slowly)

Front 5

how do centrally acting drugs work?

Back 5

not clear, but thought to create a sedative effect that allows person to relax, rest and allow muscle to repair itself; muscle relaxants are usually combined with an analgesic (aspirin or acetaminophen)

Front 6

what is the antispasmotic drug of choice?

Back 6

Dantrolene - acts directly on skeletal muscle and produces fewer side-effects

Front 7

how does intrathecal baclofen work?

Back 7

baclofen turns down the gain on the muscle stretch receptor feedback loop by enhancing presynaptic inhibition at the synapse between the muscle afferent and the motor neuron.

Front 8

what is a contra-indication for giving the drug of choice antispasmotic?

Back 8

Dantrolene is contraindicated in hepatic impairment; acute muscle spasm, pregnancy, and breast-feeding

Front 9

name the indications and contra-indications for tizanidine.

Back 9

indications: spasticity associated with MS or spinal cord injury (possibly: trigeminal neuralgia, chronic low back pain, cluster headache, spasmotic torticollis, neuropathic pain); C/I: hepatic impairment

Front 10

name muscle relaxers used for chronic low back pain.

Back 10

cyclobenzaprine (Flexeril), orphenadrine (Norflex), metaxolone, chlorzoxazone, methocarbamol, Carisoprodol (Soma)

Front 11

describe the cyclobenzaprine (Flexeril) and its S/e.

Back 11

centrally acting, structurally similar to TCAs, nocturnal muscle spasms; S/E: drowsiness, cardiac dysrhythmias, Anticholinergic (dry mouth, blurred vision, urine retention, constipation, increased IOP)

Front 12

Describe carisoprodol (Soma).

Back 12

precursor of meprobamate, centrally active, S/E: sedation, DROWSINESS, dependence (withdrawal)

Front 13

name the drug that is under investigation for uses in MS; daily doses 1000mg qid; s/e: DROWSINESS; its centrally active and inhibits polysynaptic reflexes.

Back 13

methocarbamol

Front 14

name the drug that reduces spasms, taken 400-800mg tid, s/e: nausea/DROWSINESS/Dizziness.

Back 14

metaxalone

Front 15

this drug is an analogue of diphenhydramine under investigation to be used in spinal cord injuries and has S/E: anticholinergic s/e and rare aplastic anemia.

Back 15

orphenadrine citrate