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54 Cards in this Set
- Front
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cholinergic antagonists
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block the action of Ach at muscarinic receptors
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tertiary agents
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lipid soluble
penetrates CNS better |
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quarternary agents
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positive charge
water soluble have higher ganglionic blocking to antimuscarinic activity ratio |
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Atropine
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tertiary, but penetrates CNS poorly
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Scopolamine
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tertiary, penetrates CNS better than Atropine
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Ipratropium
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Quat, little CNS activity
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drug classes with anticholinergic effects
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H1-blockers
phenothiazines TCA's carbamazepine (Tegretol) |
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anticholinergic toxicity symptoms
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1) hot as a hare, hyperthermia
2) blind as a bat (mydriasis & cycloplegia) 3) mad as a hatter (CNS stimulation) 4) dry as a bone (xerostomia) |
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other anticholinergic Side effects
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tachycardia
constipation mental confusion urinary retention |
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cholinergic antagonists
tertiary agents |
1) Atropine
2) Scopolamine 3) Benztropine mesylate 4) Trihexyphenidyl 5) Dicyclomine 6) Darifenicin 7) Homatropine 8) Cyclopentolate 9) Tropicamide |
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Atropine
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from belladonna plant
prototype of its class |
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L-hyoscyamine
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active form
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d-hyocyamine
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non-active form
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use of Atropine
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1) treat bradycardia
2) pre-op to decrease secretions 3) mydriatic for eye exam 4) counteraction for AchE-I toxicity ** No longer used for Parkinson's** |
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action of Atropine
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competitive inhibitor at autonomic postgang. cholinergic receptors (muscarinic) even in sympathetic systems at sweat glands
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Atropine at low doses
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paradoxical decrease in HR
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Atropine at higher doses
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restlessness
hallucinations disorientation |
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Scopolamine
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Transderm Scop
L-hyoscine (tertiary cholinergic antagonist) |
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Scopolamine vs Atropine
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Scopolamine: more potent than Atropine on iris, ciliary body, secretions
less potent: at heart, bronchial & GI smooth muscles |
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Scopolamine at therapeutic doses
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high incidence of CNS depression
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use of Scopolamine
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to prevent motion sickness (most common)
treatment for Parkinsonism |
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Scopolamine in WW2
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twilight sleep and lowers inhibitions
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Benztropine mesylate
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Cogentin
synthetic muscarinic antagonists (structure similar to Atropine tertiary agent |
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use of Benztropine mesylate
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used to treat Parkinsonian syndromes
extrapyramidal symptoms antihistaminic local anesthetic effects |
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Benztropine mesylate blocks?
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blocks CNS muscarinic receptors (M1) and dopamine reuptake
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Trihexyphenidyl
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Artane
synthetic antimuscarinic tertiary agents |
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use of Trihexyphenidyl
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for Parkinsonism
blocks dopamine reuptake direct antispasmodic action on smooth muscles |
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Dicyclomine
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Bentyl
cholinergic antagonist tertiary agents (but little CNS activity) |
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use of Dicyclomine
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antispasmodic in Tx of IBS
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Darifenicin
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Enablex
cholinergic antagonists tertiary agents |
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use of Darifenicin
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used to tx overactive bladder and urgency
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Darifenicin
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competitive agent
more potent at M3 receptors |
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Darifenicin bind to?
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alpha-1-acid glycoprotein
98% plasma protein bound |
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major eliminate route of Darifenicin?
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P-450 metabolism (CYP2D6 & CYP 3A4)
**caution in hepatic insufficiency or with P-450 inhibitors** |
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mojor SE of Darifenicin
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dry mouth
dry eyes constipation UTI's |
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Homatropine
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Isopto Homatropine
cholinergic antagonist tertiary agent |
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use of Homatropine
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opthalmic to produce mydriasis and cycloplegia for Dx
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contraindication of Homatropine
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pt with glaucoma or sensitivity to anticholinergics
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Cyclopentolate
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Cyclogyl
cholinergic antagonist tertiary agent |
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use of Cyclopentolate
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ophthalmic to produce mydriasis and cycloplegia for dx
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Tropicamide
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Mydriacyl
cholinergic antagonist tertiary agent |
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use of Tropicamide
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opthalmic to produce mydriasis and cycloplegia for dx
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contraindication of Tropicamide
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pt with glaucoma or a sensitivity to anticholinergics
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Homatropine
Cyclopentolate Tropicamide |
may cause temporary stinging/burning on application, and increase IOP
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cholinergic antagonists
quaternary agents |
1) Glycopyrrolate
2) Ipratropium 3) Propantheline |
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Glycopyrrolate
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Robinal
quaternary agent cholinergic antagonist |
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use of Glycopyrrolate
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GI antispasmotic
tx of bronchospasm pre-op med to decrease salivary, GI, & pulmonary secretions to decrease risk of acid aspiration during sx |
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use of Glycopyrrolate during sx
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to block the effect of vagal stimulation
to block the muscarinic stimulation seen when anticholinesterase are used as reversal agents |
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Glycopyrrolate, any CNS effects?
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No CNS effects
should not be used to tx OP toxicity |
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Ipratropium
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Atrovent
structually similar to Atropine, but its quat |
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use of Ipratropium
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bronchodialator for COPD
for acute asthma attacks rinorrhea |
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Proantheline
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Pro-Banthine
quat older drug, used infrequently now |
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use of Proantheline
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duodenal ulcers and IBS
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absorption of Proantheline
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absorption incomplete (10-25%) and variable
food further decreases absorption |