Question 1

Botulinum toxin is used to treat spasticity by injecting this drug&#10;A) intravenously&#10;B) intrathecally&#10;C) subcutaneously&#10;D) directly into the spastic muscle&#10;E) none of the above are true; botulinum toxin is not used to treat spasticity

Accepted Answer

Botulinum toxin is injected directly into the spastic muscle to treat spasticity. This medication works by blocking the release of acetylcholine at the neuromuscular junction, which reduces muscle activity and can improve range of motion and function.

Question 2

Tizanidine (Zanaflex)may help reduce spasticity in some patients by ______ receptors in the spinal cord.&#10;A) stimulating alpha-1&#10;B) inhibiting alpha-1&#10;C) stimulating alpha-2&#10;D) inhibiting alpha-2&#10;E) stimulating GABA

Accepted Answer

Tizanidine works by stimulating alpha-2 receptors in the spinal cord, which leads to decreased spasticity. It also has some activity at alpha-1 receptors, but this is not the primary mechanism of action. It does not directly affect GABA receptors.

Question 3

The muscle relaxant that directly inhibits acetylcholine release from presynaptic terminals at the skeletal neuromuscular junction is&#10;A) baclofen&#10;B) botulinum toxin&#10;C) dantrolene sodium&#10;D) tizanidine&#10;E) none of the above are true

Accepted Answer

Botulinum toxin directly inhibits acetylcholine release from presynaptic terminals at the skeletal neuromuscular junction, causing muscle paralysis. Baclofen acts on GABA receptors in the central nervous system, dantrolene sodium works by blocking calcium release from the sarcoplasmic reticulum in skeletal muscle, and tizanidine acts as an alpha-2 agonist in the central nervous system.

Question 4

Diazepam (Valium)appears to work as a muscle relaxant by increasing the inhibitory effect of ____ on alpha motor neuron activity in the spinal cord.&#10;A) norepinephrine&#10;B) epinephrine&#10;C) acetylcholine&#10;D) 5-hydroxytryptamine (serotonin)&#10;E) gamma amino-butyric acid (GABA)

Accepted Answer

Diazepam (Valium) works by enhancing the inhibitory effects of gamma amino-butyric acid (GABA) on alpha motor neuron activity in the spinal cord, leading to muscle relaxation.

Question 5

If botulinum toxin reaches the systemic circulation,it can cause toxic effects as indicated by&#10;A) generalized muscle weakness&#10;B) difficulty speaking&#10;C) difficulty swallowing&#10;D) respiratory distress&#10;E) all the above

Accepted Answer

Botulinum toxin is a potent neurotoxin that blocks the release of acetylcholine at the neuromuscular junction. If it reaches the systemic circulation, it can cause generalized muscle weakness, difficulty speaking and swallowing, and respiratory distress, which can be life-threatening. Therefore, all the above options are correct.

Question 6

The drug that inhibits spasticity by selectively inhibiting calcium release from skeletal muscle sarcoplasmic reticulum is&#10;A) diazepam&#10;B) baclofen&#10;C) dantrolene sodium&#10;D) tizanidine&#10;E) botulinum toxin

Accepted Answer

The drug that selectively inhibits calcium release from skeletal muscle sarcoplasmic reticulum is dantrolene sodium. This drug is particularly useful in treating spasticity caused by conditions such as multiple sclerosis, spinal cord injury, and cerebral palsy. The other options listed (diazepam, baclofen, tizanidine, and botulinum toxin) work by different mechanisms to treat spasticity.

Question 7

Centrally-acting antispasm drugs such as cyclobenzaprine (Flexeril)and carisoprodol (Soma)were originally thought to inhibit polysynaptic reflexes in the spinal cord (polysynaptic inhibitors)but these drugs most likely work by producing

A) decreased acetylcholine release at the neuromuscular junction
B) decreased calcium release from the sarcoplasmic reticulum
C) generalized sedation in the CNS
D) inhibition of myosin ATPase activity
E) increased vasodilation of skeletal muscle vasculature

Accepted Answer

Centrally-acting antispasm drugs, such as cyclobenzaprine and carisoprodol, are thought to work by producing generalized sedation in the CNS. They bind to receptors in the brainstem and spinal cord and can reduce muscle spasms or pain by depressing nerve impulse transmission. They are not believed to inhibit acetylcholine release or myosin ATPase activity, nor do they increase vasodilation of skeletal muscle vasculature.

Question 8

Muscle relaxant effects of botulinum toxin appear to diminish or wear off after several months because&#10;A) the immune system destroys the toxin&#10;B) the muscle hypertrophies and generates more muscle fibers&#10;C) a new presynaptic terminal &#34;sprouts&#34; from the axon was originally affected by the toxin&#10;D) the liver metabolizes the toxin&#10;E) the toxin is excreted intact in the urine

Accepted Answer

Botulinum toxin blocks the release of acetylcholine from the presynaptic terminal, which leads to muscle relaxation. However, over time, a new presynaptic terminal "sprouts" from the axon that was originally affected by the toxin, leading to the recovery of muscle function. This is why the muscle relaxant effects of botulinum toxin wear off after several months. The immune system does not destroy the toxin, the muscle does not hypertrophy and generate more muscle fibers, the liver does not metabolize the toxin, and the toxin is not excreted intact in the urine.

Question 9

Long term use of diazepam (Valium)as a muscle relaxant is often limited due to problems with&#10;A) sedation&#10;B) tolerance&#10;C) physical dependence&#10;D) all the above are true&#10;E) none of the above are true

Accepted Answer

Long term use of diazepam as a muscle relaxant can lead to sedation, tolerance, and physical dependence. Sedation can interfere with daily activities, tolerance can decrease the effectiveness of the drug over time, and physical dependence can lead to withdrawal symptoms if the drug is stopped abruptly. Therefore, these problems limit the long term use of diazepam as a muscle relaxant.

Question 10

Intrathecal administration of baclofen typically refers to drug delivery into&#10;A) the epidural space&#10;B) the subarachnoid space&#10;C) a sympathetic chain ganglion&#10;D) the third ventricle of the brain&#10;E) the gray matter of the spinal cord

Accepted Answer

Intrathecal administration refers to the delivery of a drug into the subarachnoid space, which is the space surrounding the spinal cord and filled with cerebrospinal fluid. Baclofen is commonly delivered intrathecally for the treatment of spasticity and other neurological disorders.

Deck 13: Skeletal Muscle Relaxants