Term
| What are other names for Parasympathomimetic drugs? |
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Definition
| cholinergic or cholinomimetic drugs |
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Term
| What do Parasympathomimetic drugs do? |
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Definition
| evoke responses similar to those produced by activation of the parasympathetic nervous system or stimulation of its muscarinic/nicotinic receptors |
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Term
| How are parasympathomimetic drugs classified? |
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Definition
- Direct-acting parasympathomimetic agents
- Indirect-acting parasympathomimetic agents:
"Reversible" anticholinesterases
"Irreversible" anticholinesterases |
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Term
| What is the action of Direct-acting parasympathomimetic agents? |
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Definition
| React with muscarinic receptors directly; mimic action of acetylcholine as agonists |
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Term
| What are the long-acting synthetic derivatives of acetylcholine? |
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Definition
| bethanechol +, (methacholine +, carbachol +). |
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Term
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Definition
| naturally occurring alkaloids that are direct-acting parasympathomimetic agents |
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Term
| What is the action of Indirect-acting parasympathomimetic agents? |
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Definition
| Inhibit acetylcholinesterase by binding to its anionic/esteratic site, thus preventing destruction of acetylcholine, increase synaptic levels of Ach, stimulate more receptors and prolong and intensify Ach effects on cholinergic receptors |
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Term
| How do indirect-acting parasympathomimetic agents act? |
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Definition
| Act through released Ach and need intact, functioning nerve terminals |
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Term
| Where do indirect-acting parasympathomimetic agents act? |
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Definition
| Stimulate mostly indirectly nicotinic and muscarinic receptors with slight preference for receptors at NMJ |
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Term
| What are indirect-acting parasympathomimetic agents also called? |
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Definition
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Term
| What are the two types of Reversible anticholinesterases? |
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Definition
Short-acting (minutes)
Long-acting (hours) |
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Term
| What affect does irreversible anticholinesterases have? |
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Definition
new acetylcholinesterase must be synthesized for activity to recover
Long acting (days) |
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Term
| What type of compond is irreversible anticholinesterases? |
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Definition
| organophosphorous compounds/organophosphates |
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Term
| What are the routes of parasympathomimetic agents? |
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Definition
| oral, SC, topical, other routes |
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Term
| How are substances with positive charge absorbed? |
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Definition
| Substance with a positive charge shows erratic absorption from GI-tract and does not cross BBB |
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Term
| Are Organophosphorous compounds well absorbed from skin? |
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Definition
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Term
| What is the pharmacological affect of parasympathomimetic drugs in lungs (M)? |
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Definition
Bronchoconstriction,
decrease in airflow |
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Term
What is the pharmacological affect of parasympathomimetic drugs in GI, GU (M)?
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Definition
Increased tone and peristaltic activity
Thus increase in gastric secretion |
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Term
What is the pharmacological affect of parasympathomimetic drugs in Heart (M)?
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Definition
Decreased rate, contractility, conductance
Thus slight decrease in BP |
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Term
What is the pharmacological affect of parasympathomimetic drugs in Heart (M)?
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Definition
Slight vasodilation, (nitric oxide), decrease in PR
Thus slight decr. in BP |
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Term
What is the pharmacological affect of parasympathomimetic drugs in Eyes (M)?
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Definition
Constriction of pupil (miosis), constriction of ciliary muscle
(near vision), decr. in IOP |
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Term
What is the pharmacological affect of parasympathomimetic drugs in Glands (M)?
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Definition
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Term
What is the pharmacological affect of parasympathomimetic drugs in CNS (M,N)?
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Definition
| Stimulation and/or inhibition, slight increase in cognition |
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Term
| What is the pharmacological affect of parasympathomimetic drugs in CNS (Nm)? |
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Definition
Low dose: Stimulation
Higher doses: Blocakade |
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Term
| What are the adverse reaction of Parasympathomimetic Drugs in Eye (M)? |
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Definition
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Term
What are the adverse reaction of Parasympathomimetic Drugs in GI, GU(M)?
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Definition
| Cramps, diarrhea, nausea, vomiting, involunt. micturition |
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Term
What are the adverse reaction of Parasympathomimetic Drugs in Heart(M)?
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Definition
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Term
What are the adverse reaction of Parasympathomimetic Drugs in Blood Vessels (M)?
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Definition
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Term
What are the adverse reaction of Parasympathomimetic Drugs in Eye (M)?
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Definition
| Blurred vision, decreased night vision |
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Term
| What are the adverse reaction of Parasympathomimetic Drugs in Gland (M)? |
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Definition
| Sweating, Increased secretion (saliva) |
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Term
What are the adverse reaction of Parasympathomimetic Drugs in CNS (N,M)?
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Definition
| Apathy, decreased respiration |
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Term
What are the adverse reaction of Parasympathomimetic Drugs in Skeletal Muscle (Nm)?
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Definition
| Twitching, weakness, paralysis |
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Term
| What are the contraindication of parasympathomimetic drugs in Lung (M)? |
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Definition
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Term
What are the contraindication of parasympathomimetic drugs in GI, GU (M)?
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Definition
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Term
What are the contraindication of parasympathomimetic drugs in Heart (M)?
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Definition
| Cardiac problems, dysrhythmias, hyperthyroidism |
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Term
| What are the contraindication of parasympathomimetic drugs in Blood Vessel (M)? |
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Definition
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Term
What are the contraindication of parasympathomimetic drugs in Eye (M)?
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Definition
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Term
What are the contraindication of parasympathomimetic drugs in Gland (M)?
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Definition
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Term
| What happens when there is an overdose of parasympathomimetic drugs? |
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Definition
| Bradycardia, Hypotension, Dyspnea, Skeletal muscle and Respiratory Paralysis |
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Term
| How is overdose of parasympathomimetic drugs treated? |
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Definition
| atropine, PAM, Pralidoxime |
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Term
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Definition
| removes covalently bound organophosphorous compound from enzyme |
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Term
| What is the disadvantage of PAM? |
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Definition
| enzyme complex “ages” and PAM becomes ineffective |
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Term
| What are some of the therapeutic uses of Parasympathomimetic Drugs? |
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Definition
a) Paroxysmal tachycardia
b) GI or GU atony
c) Open-angle glaucoma
d) Narrow angle glaucoma
e) Myasthenia gravis
f) Alzheimer’s disease
g) Erectile Dysfunction
h) Reversal of neuromuscular blockade by d-tubocurarine
i) Dry mouth syndrome |
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Term
| What happens in GI or GU atony? |
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Definition
| After surgery intestines or bladder may become atonic and stimulation of muscarinic receptors restores activity (bethanechol). |
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Term
| How is open angle glaucoma corrected? |
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Definition
| Stimulation of M receptors on ciliary body constricts ciliary body, pulls on longitudinal structures attached to trabecular meshwork, opens trabecular meshwork and increases outflow with reduction in IOP (pilocarpine) |
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Term
| What causes narrow angle glaucoma? |
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Definition
| Cause is narrow angle being blocked by mydriasis |
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Term
| How is narrow angle glaucoma corrected? |
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Definition
| Miosis removes block and increases outflow in narrow-angle glaucoma (pilocarpine) |
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Term
| What causes Myasthenia gravis? |
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Definition
| Autoimmune disease, destruction of Nm receptors |
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Term
| How can Myasthenia gravis be corrected? |
|
Definition
increase synaptic Ach to stimulate “spare” receptors
(watch out for overdosing!) |
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Term
| What causes open angle glaucoma? |
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Definition
| Cause is defective trabecular outflow |
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Term
| What is a cause of Alzheimer's Disease? |
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Definition
Loss of nicotinic receptors in brains of patients
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Term
| How can Alzheimer's Diseae can be treated? |
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Definition
need to increase Ach to stimulate spare receptors
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Term
| What action takes place during erection? |
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Definition
During sexual excitement, muscarinic receptors are stimulated causing cGMP formation and vessel dilation in the penis
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Term
| What causes erectile dysfunction? |
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Definition
cGMP is broken down by phosphodiesterase or PD soon
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Term
What do some drugs like sildenafil, tadalafil, verdenafil do to treat erectile dysfunction?
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Definition
Block PD, prolong action of cGMP and cause more and longer vasodilation with improved and longer erection
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Term
How does d-tubocurarine block neuromuscular junction?
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Definition
d-Tubocurarine blocks Nm receptors causing relaxation and paralysis
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Term
| How can neuromuscular blockade by d-tubocurarine be reversed? |
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Definition
Increased ACH can move drug away and restore activity
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Term
| How is dry mouth syndrome treated? |
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Definition
Stimulation of salivary glands via M receptor
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Term
Which receptor is mostly of pharmacological interest?
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Definition
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Term
| How can adrenal medulla stimulate neuromuscular junction with Ganglionic agonists? |
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Definition
They bind to Nn receptor at the adrenal medulla (Nn) and stimulate EPI secretion, which bind to the Nm receptor at neuromuscular junction and increase muscle activity
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Term
| What type of nervous system has autonomic dominance in organs? |
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Definition
parasympathetic, except sympathetic at blood vessels |
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Term
| How are autonomic ganglia stimulated? |
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Definition
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Term
| How are autonomic ganglia blocked? |
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Definition
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Term
| What are the actions of autonomic ganglia stimulation? |
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Definition
pupillary and ciliary body constriction, bradycardia, decreased airflow, increased GI/GU activity, sweating (all parasympathetic) and blood vessel constriction (sympathetic)
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Term
| What is the action of low dose of nicotine? |
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Definition
stimulation; increase in blood pressure (slight), increase or decrease in heart rate, sweating, increase in GI tone, tremor
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Term
| What is the action of high dose of nicotine? |
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Definition
nausea, salivation, vomiting, increase followed by decrease in blood pressure, irregular heart rate, blurred
vision, severe diarrhea, urination, sweating, confusion, muscular weakness, paralysis, confusion, respiratory failure, death
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Term
| How are Parasympathomimetic Drugs used therapeutically for Hypertensive crisis? |
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Definition
Blockade of sympathetic ganglia – no NE release – no alpha stimulation –vasodilation – fall in blood pressure
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Term
How are Parasympathomimetic Drugs used therapeutically for smoking cessation?
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Definition
Supplying nicotine (gum/patch)
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