test 2 misc Flashcards
what pt populations are muscarinic agonists contraindicated
Asthma
urinary or GI obstruction
hyperthyroidism - muscarinic agonist causes bradycardia and hypotension, baroreceptor reflex attempts to return the BP back to normal so it causes the release of norepinephrine from sympathetic nerves that regulate heart rate. In hyperthyroidism, norepinephrine has a larger risk of induce cardiac dysrhythmias bc they are very sensitive to the effects of norepienephrine.
pt with hypotension
peptic ulcer disease - stimulates acid production in GI
Bethanechol
Cevimeline
pilocarpine
muscarinic agonists
muscarinic agonist used in xerostomia (dry mouth) and Sjorgren syndrome
Cevimeline
Muscarinic agonist used in glaucoma
Pilocarpine
resp bronchospasm excessive bronchial secretions bradycardia hypotension Profuse salivation n/v abd pain diarrhea fecal incontinence diaphoresis lacrimation miosis
can lead to cardiovascular collapse if not treated
muscarinic Poisoning (Tox)
treatment of muscarinic poisoning
Atropine
what is the drug of choice for Myasthenia Gravis
Pyridostigmine which is a reversible cholinesterase inhibitor
responses to cholinesterase inhibitor
bradycardia bronchial constriction urinary urgency increased glandular secretions increased tone and motility of gI miosis focusing on the lens for near vision
at therapeutic doses , cholinesterase inhibitors due what to skeletal muscle
increase force of contraction
at toxic doses, cholinesterase inhibitors due what to skeletal muscle
reduce force of contraction
if administered in toxic doses cholinesterase inhibitors can produce ________ _________.
Neuromuscular blockade which can cause paralysis of the resp muscles and can be fatal
what is the drug of choice for treating poisoning caused by atropine and other drugs that cause muscarinic blockade including antihistamines and phenothiazine antipsychotics but NOT tricyclic antidepressants because this can cause seizures and cardiotoxicity
Physostigmine (cholinesterase inhibitor)
what 3 cholinesterase inhibitors are approved for Alzheimers Disease
Donepezil (Aricept)
Galantamine (Razadyne)
Rivastigmine (Exelon)
what cholinesterase inhibitor is approved for dementia of Parkinson disease
Rivastigmine (Exelon)
what is the only indication for using a irreversible cholinesterase inhibitor (organophosphate cholinesterase inhibitors) and what drug is it?
glaucoma
echothiophate (Phospholine Iodide)
this class of drugs was used in WWII for nerve agents
Cholinesterase reactivator used to reverse the inhibition of cholinesterase specific to organophosphates
this will not work for reversal of poisonings from reversible cholinesterase inhibitors
Pralidoxime
toxic doses of irreversible cholinesterase inhibitors produce what time of effects (cholinergic crisis)
excessive muscarinic, nocotinic and CNS effects
profuse secretions from salivary and brochial glands involuntary urination involuntary deification laryngospasm bronchoconstriction
nicotinic effects
muscle weakness
cramps
twitching
what are common means of poisoning my a cholinesterase inhibitor
insectasides
treatment for cholinergic crisis from toxicity of cholinergic inhibitors
atropine ->reduce muscarinic stimulation
Pralidoxime ->reverse inhibition of cholinesterase
benzodiazepine (diazepam) to suppress convulsions
mechanical ventilation and oxygen for resp depression/failure
treatment for Myasthenia Gravis
Reversible cholinesterase inhibitors
Pyridostigmine
only symptom relief - will need to be on this long term
a neuromuscular disorder characterized by fluctuating muscle weakness and a predisposition to rapid fatigue
symptoms
ptosis (drooping eyelids)
difficulty swallowing
weakness of skeletal muscles
severe symptoms
difficulty breathing from weakness of resp muscles
Myasthenia Gravis
why does MG occur
autoimmune process pt immune system attacks nicotinic M receptors
dosing for MG
pt taught to adjust doses
signs of undermedication - ptosis, difficulty swallowing
signs of over med -excessive salivation and other muscarinic responses
may need more 30-60 min prior to exertion such as eating or shopping
balance to prevent myasthenic crisis to cholinergic crisis
what is myasthenic crisis
pt who are not adequately medicated
extreme muscle weakness caused by insufficient ACh at the NMJ - can result in death if not treated by paralysis of resp muscles
