drug therapy for treatment of MG, Alzheimer's, and urinary retention Flashcards
describe what happens when the parasympathetic nervous system is activated
- constricts pupils
- stimulates salivation
- slows heart
- constricts bronchioles
- stimulate digestion
- stimulates gallbladder
- contracts bladder
- stimulates sex organs
describe what happens when the sympathetic nervous system is activated
- dilates pupils
- inhibits salivation
- accelerates heart
- dilates bronchioles
- inhibits digestion
- stimulates release of glucose
- secretes epinephrine and norepinephrine
- relaxes bladder
- inhibits sex organs
true or false?
direct-acting cholinergic medications readily enter the central nervous system
false
rationale: direct acting cholinergic medications do not readily enter the central nervous system; thus, their effects occur primarily in the periphery
define myasthenia gravis
chronic autoimmune neuromuscular disease, weakness and rapid fatigue of muscles under voluntary control
describe the etiology of myasthenia gravis
defect in the transmission of nerve impulses to muscles
describe the pathophysiology of myasthenia gravis
occurs when normal communication between the nerve and muscle is interrupted at the neuromuscular junction
describe the clinical manifestations of myasthenia gravis
- facial expression and swallowing, weakness of eye muscles
- diplopia (double/burred vision)
- dysphagia (difficulty swallowing)
- dysarthria (slurred speech)
- SOB
- -*hallmark sx: symptoms increase with exertion and improve with rest
describe drug therapy used to treat myasthenia gravis
- cholinergic drugs
- acetylcholinesterase inhibitor drugs
define neostigmine
used for long term treatment of myasthenia gravis and as an antidote for nondepolarizing skeletal muscle relaxants used in surgery
what is the use of neostigmine
diagnosis and treatment of myasthenia gravis. reverse the action of nondepolarizing neuromuscular agents
describe the pharmacokinetics of neostigmine
administered slowly intravenously, metabolized by liver, excreted in the kidneys
describe the action of neostigmine
- decreases the inactivation of acetylcholine in the synapses by the enzyme acetylcholinesterase
- by interfering with the breakdown of Ach, stimulates both nicotinic and muscarinic receptors which are involved in muscle contraction
describe the adverse effect of neostigmine
- cardiovascular and respiratory
- cardiac dysrhythmias, decreased cardiac output, hypotension, cardiac arrest, and respiratory depression which may indicate a cholinergic crisis
what are some contraindications of neostigmine
hypersensitivity, lung disease, heart disease, benign prostatic hypertrophy
what are some nursing implications regarding neostigmine
- preventing interactions: atropine/corticosteroids (will decrease effect)
- administerings the medication: with food/milk to decrease risk of gastric distress, ulceration
describe assessing for therapeutic effects with neostigmine
- increase in muscle strength
- decreased difficulty with chewing, swallowing, and speech
- absent ptosis
describe assessing for adverse effects with neostigmine
- increase in central nervous system effects such as convulsions, dizziness, drowsiness, secretions, broncho and laryngospasms, and respiratory failure
- pyridostigmine: indirectly increasing the concentration of acetylcholine at the NMJ and promoting increased cholinergic nicotinic receptor activation - has no unwanted CNS effect and does not cross blood brain barrier
describe pt teaching with neostigmine
- educate on wearing medical alert identification device
- rest between activities
- increase reporting and awareness to an increase in muscle weakness
- may have complaints of abdominal cramps, diarrhea, and difficulty breathing, these are all concerns
describe cholinergic crisis
- occurs from an overdose of acetylcholinesterase inhibitors
- this is an emergency, important to teach pts about the signs and symptoms
what are the signs and symptoms of cholinergic crisis
extreme weakness
- salivation
- lacrimation
- urinary incontinence
- diarrhea
- GI upset
- emesis
what is the treatment for cholinergic crisis
- atropine
- works on the muscarinic receptors (not nicotinic), so you will see changes in the heart, smooth muscles, and glands when this drug is administered to reverse or stop the cholinergic crisis
what are the characteristics of overstimulation of PNS
B: bronchoconstriction
A: apnea
G: gray vision
P: pupil constriction
U: urinary increase
D: diaphoresis
D: defecation
L: lacrimation
E: emesis
S: seizures