Module 4 Pearls Deck 2 Flashcards
Cholinergic Antagonists/Blockers also known as
anticholinergics, parasympatholytics,
muscarinic antagonists
Cholinergic Antagonists/Blockers block
of acetylcholine (ACh) in the cholinergic synapses, and prevent ACh from binding at receptor sites
Cholinergic Antagonists/Blockers produce many
Produce many of the same effects in the body as
adrenergic agonists
two main types of Cholinergic Antagonists/Blockers
Muscarinic antagonists and Nicotinic antagonists
Muscarinic MOA
block Ach from binding to muscarinic receptors in the parasympatheitc nervous system and inhibit some transmission in the sympathetic nervous system as well
Nicotinic MOA
block Ach from binding to the nicotinic receptors in the ganglia of the para and sympatheitc nervous systems
Cholinergic antagonists have the opposite effect
of cholinergic agonists
Cholinergic Antagonists: General Effects on the Body
Cholinergic antagonists
Increase blood pressure and pulse rate
• Increase bronchial dilation
• Produce mydriasis (dilated pupils) and cycloplegia (paralysis of ciliary muscle)
• Decrease sweating
• Reduce secretions and dry out mucous membranes
• Decrease gastric motility
• Increase urinary retention
Muscarinic antagonists are NOT considered
first line due to side effects:
side effects of muscarinic antagonists
Tachycardia and arrhythmias
• Mydriasis and cycloplegia, resulting in photophobia and increased intraocular pressure
• Dry eyes
• Dry mouth (xerostomia)
• Urinary retention, which poses a threat to males with prostate problems
• Decreased sweating that can lead to hyperthermia if the body cannot regulate its temperature
muscarinic receptors are found in
many different organ systems
specific cholinergic Antagonists examples
(atropine, ipratropium bromide (Atrovent)
Central acting cholinergic antagonists examples and use
Parkinson’s
Uses of Cholinergic Blocking Drugs
Block vagal impulses to heart
• Suppress or decrease
– Respiratory secretions (preoperative medication)
– Bladder spasms
• Relax sphincter muscle of iris
• Treat tremors/rigidity of parkinsonism
• Treat side effects of psychotropic medications
Cholinergic crisis is a serious condition that can result from
overdosage of AChE
inhibitors. This condition is also caused by poisoning from chemical agents such as:
– Sarin, a toxic nerve agent used in chemical warfare
– Malathion, parathion, and other organophosphate insecticides
_____ an anticholinergic and muscarinic antagonist, is the primary drug
used to treat cholinergic crisis.
Atropine
Atropine is used with ___ as an antidoe for sarin or insecticide poisening
Pralidoxime chloride (2-PAM, Protopam Chloride)
Pralidoxime chloride is classified as a
cholinesterase receptor
agonist and a detoxification agent. It helps restore normal transmission at
neuromuscular junctions.
Cholinesterase Inhibitors
Indirect cholinergic agnonists
Prevents the destruction of ACh by inhibiting AChE thus increasing ACh activity
Seizure
Abnormal discharge of neurons
• Disruption of neuron stability may trigger abnormal activity
and seizures
factors that precipitate seizures
Sleep deprivation, high caffeine intake, hyperventilation, stress,
hormonal changes, sensory stimuli, drug/alcohol use,
infections, fever, metabolic disorders
Three terms used interchangeably for seizures
Anti-seizure drugs
– Antiepileptic drugs (AEDs)
– Anticonvulsants
Anti-seizure drugs act by
suppressing the brain’s neuronal
discharges.
Anti-seizure medications are
sometimes classified according to
their mechanism of action:
Slowing neuronal firing rates by increasing gamma-aminobutyric acid (GABA) levels • Blocking the channels responsible for neuronal firing • Blocking AMPA receptors, by medications such as Perampanel (Fycompa)
Examples of drugs that work on gaba
benzodiazapines, phenobarbitol
Muscle Relaxants and Antispasmodics
Centrally acting
baclofen (Lioresal) cyclobenzaprine (Flexeril),
carisoprodol (Soma),
chloroxazone (Paraflex, Parafon Forte), metaxalone (Skelaxin), methocarbamol
(Robaxin), orphenadrine (Banflex, Norflex), and tizanidine
(Zanaflex)
Muscle Relaxants and Antispasmodics direct acting examples
dantrolene (Dantrium) and botulinum toxin type A (Botox)
Centrally Acting Skeletal Muscle Relaxants MOA
Unknown
Centrally Acting Skeletal Muscle Relaxants Contraindication
specfic for each drug, all are contraindicated in pregnancy
Centrally Acting Skeletal Muscle Relaxants ADR
CNS sedation, respiratory
depression; chloroxazone may
be hepatotoxic
Centrally Acting Skeletal Muscle Relaxants Interactions and patient educaton
Drug interactions: additive
sedation with CNS depressants (respiratory depression) this is why there are drug interactions and why its important to discuss this with patients
• Patient education: appropriate
use, CNS sedation
Decrease in pain from centrally acting skeletal muscle relaxants is due to
decrease in spasm not anelgesic properties
Direct acting muscle relaxants: Dantrolene: used to treat
spasticity associated with upper neuron
disorders
dantroline contraindicated in
active liver diseases
dantroline ADR
CNS depression, confusion
dantroline patient education
titration schedule
Botulinum toxin type a
injected to provide localized reduction in muscle activity
botulinum toxin type a may
spread from the site of injection to mimic boulism may require mechanical ventilation
botox works by
blocking the release of AcH
dantroline works by blocking
dantroline release
danroline helps relax
sacromeres
botox can be used for
migraines
