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PHARMA > SKELETAL 1 > Flashcards

SKELETAL 1 Flashcards

1
Q

Neuromuscular paralysis that results from persistent depolarization of the end plate (eg, by succinylcholine).

A

Depolarizing blockade

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2
Q

A phase of blockade by a depolarizing blocker during which the end plate repolarizes but is less than normally responsive to agonists (acetylcholine or succinylcholine)

A

Desensitization

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3
Q

Hyperthermia that results from massive release of calcium from the sarcoplasmic reticulum, leading to uncontrolled contraction and stimulation of metabolism in skeletal muscle.

A

Malignant hyperthermia

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4
Q

Neuromuscular paralysis that results from pharmacologic antagonism at the acetylcholine receptor of the end plate (eg, by tubocurarine)

A

Nondepolarizing blockade

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5
Q

A drug that reduces abnormally elevated muscle tone (spasm) without paralysis (eg, baclofen, dantrolene)

A

Spasmolytic

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6
Q

Synonym for nonpolarizing blockade

A

Stabilizing blockade

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7
Q

The neuromuscular blocking drugs, which act at the skeletal myoneural junction, are used to produce ____ to facilitate surgery or assisted ventilation.

A

muscle paralysis

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8
Q

The ___ drugs, most of which act in the CNS, are used to reduce abnormally elevated tone caused by neurologic or muscle end plate disease.

A

spasmolytic

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9
Q

Skeletal muscle contraction is evoked by a ___ transmission process.

A

nicotinic cholinergic

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10
Q

One neuromuscular blocker used clinically is an agonist at the nicotinic end plate receptor (depolarizing type).

A

succinylcholine

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11
Q
  • All agents are given parenterally.
  • They are highly polar drugs and do not cross the blood-brain barrier.
  • Drugs that are metabolized (eg, mivacurium, by plasma cholinesterase) or eliminated in the bile (eg, vecuronium) have shorter durations of action (10–20 min) than those eliminated by the kidney (eg, metocurine, pancuronium, pipecuronium, and tubocurarine), which usually have durations of action of less than 35 min.
A

Nondepolarizing Neuromuscular Blocking Drug

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12
Q

Nondepolarizing Neuromuscular Blocking Drug that At high blood levels, it may cause seizures.

A

laudanosine

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13
Q

A stereoisomer of atracurium, is also inactivated spontaneously but forms less laudanosine and currently is one of the most commonly used muscle relaxants in clinical practice.

A

Cisatracurium

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14
Q

Prototype drug that are neuromuscular blockers that are quaternary amines and structurally related to acetylcholine.

A

tubocurarine

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15
Q
  • Nondepolarizing drugs prevent the action of ACh at the ____
  • They act as ___ blockers → the blockade can be overcome by increasing the amount of agonist [ACh] in the synaptic cleft
  • They behave as though they compete with ACh at the receptor, and their effect is reversed by ___ inhibitors.
A
  • skeletal muscle end plate
  • surmountable
  • cholinesterase
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16
Q

Has the most rapid onset of available nondepolarizing drugs.

A

rocuronium (60-120Ss)

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17
Q

Is composed of 2 Ach molecules linked end to end. It is metabolized by cholinesterase (butyrylcholinesterase or pseudocholinesterase) in the liver and plasma. Acts like a nicotinic agonist and depolarizes the neuromuscular end plate.

A

Succinylcholine

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18
Q

Because tension cannot be maintained in skeletal muscle without periodic repolarization and depolarization of the end plate, continuous depolarization results in

A

muscle relaxation and paralysis

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19
Q

When given by continuous infusion, the effect of succinylcholine changes from continuous depolarization ___ to gradual repolarization with resistance to depolarization ____

A
  • (phase I)

- (phase II)

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20
Q

The initial depolarization of succinylcholine is often accompanied by ___ (prevented by pretreatment with small doses of a nondepolarizing blocker).

A

twitching and fasciculations

21
Q

This is best accomplished by administration of __ such as neostigmine or pyridostigmine.

A

cholinesterase inhibitors

22
Q

The paralysis produced by the depolarizing blocker succinylcholine is __ by cholinesterase inhibitors during phase I. During phase II, the block produced by succinylcholine is usually ____ by cholinesterase inhibitors.

A
  • increased

- reversible

23
Q

The action of full doses of ___ leads directly to respiratory paralysis. If mechanical ventilation is not provided, the patient will asphyxiate.

A

neuromuscular blockers

24
Q

Autonomic ganglia are stimulated by ___ and weakly blocked by ___.

A
  • succinylcholine

- tubocurarine

25
Q

Succinylcholine ____ cardiac muscarinic receptors, whereas pancuronium is a moderate blocking agent and causes

A
  • activates

- tachycardia

26
Q

Specific effects of succinylcholine

A
  • Muscle pain
  • hyperkalemia
  • regurgitation with possible aspiration of gastric contents
27
Q

Inhaled anesthetics, especially isoflurane, strongly ___ and ___ neuromuscular blockade.

A
  • potentiate

- prolong

28
Q

A rare interaction of succinylcholine (and possibly tubocurarine) with inhaled anesthetics can result in

A

malignant hyperthermia

29
Q

A very early sign of this potentially life- threatening condition in succinylcholine is

A

contraction of the jaw muscles (trismus)

30
Q

Are more sensitive to the actions of the nondepolarizing blockers, and doses should be reduced in these patients.

A

Older patients (>75 years) and those with myasthenia gravis

31
Q

The goal of spasmolytic therapy in both chronic and acute conditions is reduction of excessive skeletal muscle tone without

A

reduction of strength

32
Q

They act in the CNS and in one case in the skeletal muscle cell rather than at the neuromuscular end plate.

A

spasmolytic drugs

33
Q

The spasmolytic drugs used in treatment of the chronic conditions mentioned previously include:
➢ a benzodiazepine
➢ a γ-aminobutyric acid (GABA) agonist
➢ a congener of clonidine
➢ an agent that acts on the sarcoplasmic reticulum of skeletal muscle

A

➢ diazepam, a benzodiazepine
➢ baclofen, a γ-aminobutyric acid (GABA) agonist
➢ tizanidine, a congener of clonidine
➢ dantrolene, an agent that acts on the sarcoplasmic reticulum of skeletal muscle.

34
Q

Injected into selected muscles can reduce pain caused by severe spasm and also has application for ophthalmic purposes and in more generalized spastic disorders (eg, cerebral palsy).

A

Botulinum toxin

35
Q

Gabapentin and pregabalin antiseizure drugs, have been shown to be effective spasmolytics in patients with

A

multiple sclerosis

36
Q

Three of the drugs act in the spinal cord. All 3 drugs reduce the tonic output of the primary spinal motoneurons.

A
  • baclofen,
  • diazepam,
  • tizanidine
37
Q

Acts as a GABAB agonist at both presynaptic and postsynaptic receptors, causing membrane hyperpolarization. Presynaptically, by reducing calcium influx, it decreases the release of the excitatory transmitter glutamic acid; at postsynaptic receptors, baclofen facilitates the inhibitory action of GABA.

A

Baclofen

38
Q

facilitates GABA-mediated inhibition via its interaction with GABAA receptors.

A

Diazepam

39
Q

an imidazoline related to clonidine with significant α2 agonist activity, reinforces presynaptic inhibition in the spinal cord.

A

Tizanidine

40
Q

acts in the skeletal muscle cell to reduce the release of activator calcium from the sarcoplasmic reticulum via interaction with the ryanodine receptor (RyR1) channel. Is also effective in the treatment of malignant hyperthermia.

A

Dantrolene

41
Q

Causes somewhat less sedation than diazepam, and tolerance occurs with chronic use—withdrawal should be accomplished slowly.

A

Baclofen

42
Q

may cause asthenia, drowsiness, dry mouth, and hypotension.

A

Tizanidine

43
Q

causes significant muscle weakness but less sedation than either diazepam or baclofen.

A

Dantrolene

44
Q

a typical member of this group, is believed to act in the brain stem, possibly by interfering with polysynaptic reflexes that maintain skeletal muscle tone. may cause confusion and visual hallucinations in some patients.

A

Cyclobenzaprine

45
Q

Patients with___ often have decreased levels of plasma cholinesterase, thus prolonging the duration of action of mivacurium or succinylcholine.

A

renal failure

46
Q

Which of the following drugs is the most effective in the emergency management of malignant hyperthermia?

A

Dantrolene

47
Q

The clinical use of succinylcholine, especially in patients with diabetes, is associated with
(A) Antagonism by pyridostigmine during the early phase of blockade
(B) Aspiration of gastric contents
(C) Decreased intragastric pressure
(D) Histamine release in a genetically determined population
(E) Metabolism at the neuromuscular junction by acetylcholinesterase

A

Aspiration of gastric contents

48
Q

Myalgias are a common postoperative complaint of patients who receive large doses of succinylcholine, possibly the result of muscle fasciculations caused by depolarization. Which drug administered in the operating room can be used to prevent postoperative pain caused by succinylcholine?

A

Cisatracurium

PHARMA (26 decks)

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