ANS Mimetics & Lytics Flashcards by Bec Crawford

Parasympathetic Presynaptic Receptor and Neurotransmitter

N - Nicotinic (Cholinergic)

ACh - Acetylcholine

How well did you know this?

Not at all

Perfectly

Parasympathetic Postsynaptic Receptor and Neurotransmitter

M1-5 - Muscarinic (Cholinergic)

ACh - Acetylcholine

How well did you know this?

Not at all

Perfectly

Direct Parasympathomimetic (1)

Bethanechol (PO)

How well did you know this?

Not at all

Perfectly

Reversible, Indirect Parasympathomimetics (3): Acetylcholinesterase Inhibitor, Cholinesterase Inhibitor, Anticholinesterase, Cholinergic

Edrophonium (inj)
Neostigmine (inj, PO)
Pyridostigmine (inj, PO, ER)

How well did you know this?

Not at all

Perfectly

Direct Parasympatholytics (4): Muscarinic Antagonist, Anticholinergic, Antimuscarinic

Atropine (inj, PO, ophth)
Glycopyrrolate (inj)
Oxybutynin (PO, ER)
Propantheline (PO, ER)

How well did you know this?

Not at all

Perfectly

M3 selectivity at detrusor muscle for contraction of the bladder; also stimulates contraction of GI smooth muscle

Bethanechol

How well did you know this?

Not at all

Perfectly

Shortest to Longest Onset and Duration of Action for Reversible, Indirect Parasympathomimetics: Edrophonium, Neostigmine, Pyridostigmine

Edrophonium 1min to 10min

How well did you know this?

Not at all

Perfectly

__________ is used for the Tensilon Response test for canine myasthenia gravis.

Edrophonium

How well did you know this?

Not at all

Perfectly

__________ is most commonly used to treat canine myasthenia gravis.

Pyridostigmine

How well did you know this?

Not at all

Perfectly

_________ crisis: caused by not enough ACh/receptor interactions

myasthenic

How well did you know this?

Not at all

Perfectly

__________ crisis: caused by too many ACh/receptor interactions

cholinergic

How well did you know this?

Not at all

Perfectly

Carbaryl ad Propoxur are examples of Carbamate insecticides, which are __________, indirect parasympathomimetics.

reversible

How well did you know this?

Not at all

Perfectly

Chlorpyrifos, Diazinon and Malathion are examples of Organophosphate insecticides, which are __________, indirect parasympathomimetics.

irreversble

How well did you know this?

Not at all

Perfectly

Which is metabolized faster, carbamate or organophosphate insecticides?

carbamate

How well did you know this?

Not at all

Perfectly

Carbamate insecticides are less selective for motor end plate nicotinic receptors than Edrophonium, Neostigmine or Pyridostigmine; but more likely to cross the blood-brain barrier leading to CNS signs such as seizure. True or False

True

How well did you know this?

Not at all

Perfectly

Primary Signs: Muscarinic (associated with Carbamate and Organophosphate toxicity)

DUMBBELS
Diarrhea
Urination
Miosis (+++ pupil constriction)
Bronchospasm
Bradycardia
Emesis (vomiting)
Lacrimation
Salivation

How well did you know this?

Not at all

Perfectly

Secondary Signs: Nicotinic (associated with Carbamate and Organophosphate toxicity)

muscle tremors
weakness
paralysis
CNS excitement less common

How well did you know this?

Not at all

Perfectly

Tertiary Signs (associated with Carbamate and Organophosphate toxicity)

Nicotinic Blockade

How well did you know this?

Not at all

Perfectly

Treat carbamate or organophosphate toxicity with __________ for nonspecific counteraction of physiologic and muscarinic effects.

Atropine

How well did you know this?

Not at all

Perfectly

__________ is required in early stages of onset of organophosphate toxicity in order to break the chemical bonds prior to “aging” (irreversible development of strong bond holding organophosphate to the active site of acetylcholinesterase)

Antidote: Pralidoxime (2-PAM)

How well did you know this?

Not at all

Perfectly

Prototypical nonspecific muscarinic antagonist:

Atropine

How well did you know this?

Not at all

Perfectly

Atropine is an __________ originally extracted from the belladonna plant.

alkaloid (Alkaloid, any of a class of naturally occurring organic nitrogen-containing bases. Alkaloids have diverse and important physiological effects on humans and other animals. Well-known alkaloids include morphine, strychnine, quinine, ephedrine, and nicotine.)

How well did you know this?

Not at all

Perfectly

Glycopyrrolate has a slower onset of action and longer duration of action than Atropine. True or False

True: Glycopyrrolate onset 30min, duration 2-3h

How well did you know this?

Not at all

Perfectly

CAUTION in __________ with atropine, since it decreases intestinal motility and may lead to adynamic ileus.

horses, equids

How well did you know this?

Not at all

Perfectly

_________ is the paralysis of the ciliary muscle of the eye leading to loss of lens accommodation and blurred vision. CAUTION in _________ with atropine, since blurred vision can caused panic.

cycloplegia; horses

_________ have endogenous atropinases and thus metabolize atropine rapidly, limiting its clinical utility in this species.

rabbits

Atropine is indicated for __________ crisis.

cholinergic

Shortest to Longest Onset and Duration of Action for Parasympatholytics: Atropine, Glycopyrrolate

Atropine

Which is more arrhythmogenic, Atropine or Glycopyrrolate?

Atropine

Glycopyrrolate is a quaternary ammonium compound; it does not cross the blood-brain barrier and is therefore less likely to cause CNS effects. True or False

True

Glycopyrrolate is perferred over Atropine in rabbits. True or False

True

Pharmacokinetics and Indications for Oxybutynin are congruent with those of Propantheline; EXCEPT Oxybutynin is widely distributed whereas Propantheline does not cross the blood-brain barrier. True or False

True

At normal doses of Oxybutynin and Propantheline, the __________ and __________ appear to be the most affected.

bladder, intestinal tract (large intestine***)

Antispasmodic indicated for the GI tract:

Aminopentamide

Antispasmodic indicated for colic in equids and also used to treat bradycardia:

Buscopan (N-Butylscopolammonium Bromide)

Parasympathetic Effects: EYE (2)

1) contraction of ciliary muscle: lens accommodation for myopia (short/near-sightedness) 2) contraction of iris sphincter muscle for miosis (constriction)

Sympathetic Effects: EYE (3)

1) relaxation of ciliary muscle: lens accommodation for hypermetropia (long/far-sightedness) 2) contraction of iris radial muscle for mydriasis (dilation) 3) decrease aqueous humor production

Parasympathetic Effects: HEART (3)

1) decreased heart rate: bradycardia 2) decreased contractility: -ve inotropy 3) decreased AV node conduction

Sympathetic Effects: Beta 1: HEART (3)

1) increased heart rate: tachycardia 2) increased contractility: +ve inotropy 3) increased automaticity and increased AV node conduction

Parasympathetic Effects: VASCULATURE (1)

1) indirect vasodilation through release of endogenous nitrous oxide (NO) from endothelium

Sympathetic Effects: VASCULATURE (3)

1) Alpha 1 - vasoconstriction 2) Beta 2 - vasodilation 3) Alpha 2 - various (vasoconstriction/dilation)

Parasympathetic Effects: LUNG (2)

1) bronchoconstriction | 2) increase respiratory secretions

Sympathetic Effects: Beta 2: LUNG (1)

Bronchodilation

Parasympathetic Effects: GI TRACT (3)

1) increase motility 2) relax sphincters 3) stimulate secretion

Sympathetic Effects: Alpha 1, Beta 1, Beta 2: GI TRACT (3)

1) decrease motility 2) contract sphincters 3) inhibit secretion

Parasympathetic Effects: URINARY BLADDER (2)

1) contract detrusor | 2) relax sphincter

Sympathetic Effects: Alpha 1, Beta 2: URINARY BLADDER (2)

1) Alpha 1: contract sphincter | 2) Beta 2: relax detrusor muscle

DRUG + ACTION @ urinary bladder: contract detrusor muscle

Bethanechol: Direct Parasympathomimetic (M3+++)

DRUG + ACTION @ urinary bladder: contract internal sphincter

Phenylopropanolamine, Estrogens: Mixed Sympathomimetic

DRUG + ACTION @ urinary bladder: relax detrusor muscle

Oxybutynin or Propantheline: Direct Parasympatholytics

DRUG + ACTION @ urinary bladder: relax internal sphincter

Phenoxybenzamine (Alpha nonselctive) or Prazosin (Alpha 1): Direct Sympatholytics

Cholinergic Receptors (2)

Nicotinic + Muscarinic

Nicotinic receptors are ________ receptors.

ionotropic

Muscarinic receptors are ________ receptors.

metabotropic (g protein coupled)

Nicotinic: Nm subtype represents

Nm are nicotinic receptors found at the neuromuscular junction (NMJ)

Nicotinic: Nn subtype represents

Nn are nicotinic receptors found at CNS and autonomic ganglia

There are _____ subtypes of muscarinic receptors:

M 1, 3, 5 are ________

stimulatory

M 2, 4 are ________

inhibitory

Adrenergic Receptors (2)

Alpha + Beta

Both Alpha and Beta receptors are ________ receptors.

metabotropic (g protein coupled)

There are _____ subtypes of alpha receptors:

There are _____ subtypes of beta receptors:

Parasympathetic signs are observed with the use of ________ and ________ drugs.

Parasympathomimetic and Sympatholytic

Sympathetic signs are observed with the use of ________ and ________ drugs.

Sympathomimetic and Parasympatholytic

Both endogenous and synthetic catecholamines have ___ oral bioavailability but are readily absorbed from the respiratory tract (inhalation or nebulisation).

low

Direct Sympathomimetics: Endogenous Catecholamines (3)

Epinephrine (inj) Norepinephrine (inj) Dopamine (inj)

Direct Sympathomimetics: Synthetic Catecholamines (4)

Dobutamine (inj) Isoproterenol (inj) Phenylephrine (inj, PO, intranasal, ophth) Ractopamine/Zilpaterol BUT PHENYLEPHRINE AND RACTOPAMINE IS NOT TECHNICALLY A CATECHOLAMINE

Epinephrine, an adrenergic agonist, activates 5 receptors:

1) Alpha 1 2) Alpha 2 3) Beta 1 4) Beta 2 5) Beta 3

Epinephrine @ Alpha 1:

vasoconstriction (at high doses)

Epinephrine @ Beta 2:

bronchodilation, vasodilation (at low doses)

Epinephrine @ Beta 1:

cardiac contraction

Epinephrine indications (3):

1) cardiac arrest 2) anaphylaxis 3) vasopressor effect

Norepinephrine, an adrenergic agonist, activates 3 receptors:

1) Alpha 1* 2) Alpha 2* 3) Beta 1

Which is the stronger vasocontrictor, Epi or Norepi; leading to strong baroreceptor response and decrease in heart rate and contractility in spite of Beta 1 effects?

NE (reflex vagal bradycardia as a result of baroreceptor response is therefore more common with no repinephrine)

Avoid extravasation with ________ and ________.

Norepinephrine and Dopamine

Dopamine and Dobutamine have a very _____ half life.

short (minutes)

Dopamine action @ low to medium dose

peripheral dopamine receptor agonist: dilation of vascular beds (renal, mesenteric, coronary, intercerebral)

Dopamine action @ medium to high dose

Beta 1 agonist (+ve inotrope, +ve chronotrope)

Dopamine action @ high dose

Alpha 1 agonist (vasoconstriction with NE release), Beta 1 agonist (+ve inotrope, +ve chronotrope)

Dobutamine, a synthetic catecholamine that act as direct sympathomimetics, acts primarily at ______ receptors, with minor action at ______ and ______ receptors.

Primary: Beta 1 Minor: Alpha 1, Beta 2

Isoproterenol, a synthetic catecholamine that act as direct sympathomimetics, acts primarily at ______ and ______ receptors.

Beta 1 + Beta 2

Phenylephrine is a synthetic catecholamine that acts as a direct sympathomimetic at _____ receptors, indicated for treatment of hypotension and shock.

Alpha 1

Direct Sympathomimetics: Selective Beta 2 Agonists (4)

Albuterol Clenbuterol Terbutaline Isoxuprine

Albuterol, Clenbuterol, Terbutaline and Isoxuprine are agonists at _____ and minor agonists at ______ receptors.

Primary Agonist: Beta 2 | Minor Agonist: Beta 1

Nonspecific alpha adrenergic antagonist or alpha blocker, direct sympatholytic, indicated for the treatment of a hypertonic urethral sphincter (drug will relax sphincter) and pheochromocytoma

Phenoxybenzamine

Specific Alpha 1 antagonist or Alpha 1 blocker, direct sympatholytic, indicated for the treatment of a hypertonic urethral sphincter (drug will relax sphincter)

Prazosin

Class II antiarrhythmics indicated for the treatment of tachycardia:

beta adrenergic antagonists or beta blockers

Nonselective beta blocker may also be considered an inverse agonist.

Propanolol

Selective Beta 1 blocker

Atenolol, Esmolol

Oral bioavailability of propanolol is ___ to ___% due to significant first-pass metabolic effect; thus the oral dose is significantly greater than the injectable on a mg/kg basis.

2 to 27%

Propanolol is indicated for its beta 2 blockade effects: (3)

bradycardia, bronchospasm, hypotension; bradycardia by decreasing SA and AV node conduction and by decreasing cardiac output and myocardial oxygen demand

Propanolol is indicated in the treatment of: (3)

supraventricular tachyarrhythmias subsequent to feline hyperthyroidism and methylxanthine/chocolate toxicosis

Propanolol is mostly secreted as metabolites in

urine

Propanolol readily crosses the blood-brain barrier. True or False

True

The half life for propanolol is ____

1-2h

Degree of passing the blood-brain barrier among beta blockers:

Propanolol (readily crosses) > Atenolol > Esmolol (does not cross)

Half life among beta blockers:

Atenolol (2h) > Propanolol > Esmolol (20min)

Propanolol has membrane stabilizing effects where as Esmolol lacks these effects.

True

Atenolol requires minimal liver metabolism (___% excreted in the urine and ___% excreted in the feces.)

50/50

Atenolol is a better choice for patients with respiratory disease due to Beta 1 selectivity with lack of Beta 2 effects that Propanolol antagonises. True or False

True

Indirect Sympatholytic, blocks vesicular monoamine transporters thus reducing norepinephrine uptake into vesicles, leading to reduced NE storage and mediator depletion: used as a calming agent for equines in situations such as long term stall rest

Reserpine

______ ______ ______ are indicated primarily for treatment of asthma (feline) and COPD (equine).

Selective Beta 2 Agonists (Direct Sympathomimetics): Albuterol, Clenbuterol, Terbutaline

Selective Beta 2 Agonist, Direct Sympathomimetic, indicated as a peripheral vasodilator and tocolytic (uterine relaxation).

Isoxuprine

Nonselective Beta Agonist: activation of Beta 1+2+3: indicated as a partitioning agent for increase of muscle deposition in late finishing food production animals

Ractopamine/Zilpaterol

Indirect Sympathomimetics: 3 Groups

1) Tricyclic Antidepressants 2) Monoamine Oxidase Inhibitors (MAOIs) 3) Illicit Drugs

Illicity Drugs as Indirect Sympathomimetics:

Amphetamine + Cocaine

Amphetamine MOA

blocks NE release

Cocaine MOA

blocks NE re-uptake

Monoamine Oxidase Inhibitor MOA

inhibit MAO-B thus inhibiting the breakdown of dopamine; at high doses can also inhibit MAO-A thus inhibiting the breakdown of norepinephrine; also metabolises amphetamine to methamphetamine

Mixed Sympathomimetics indicated for indirect increase in release of Norepi

Phenylpropanolamine + Ephedrine/Pseudoephedrine

Phenylpropanolamine (PPA) acts primarily to increase norephinephrine release at ___________: Mixed Sympathomimetic

the neck of the bladder (urethral sphincter)

Ephedrine is indicated for use as a CRI to maintain ___________ under anaesthesia.

blood pressure

Ephedrine can be a component of some Chinese Herbal Therapies such as _____ ________.

Ma Huang

________ to PPA is seen in human patients but not veterinary patients.

tachyphylaxis

________ increase expression of Alpha 1 receptors in the internal urinary sphincter; synergism is observed when PPA is used in conjunction with hormonal therapies.

Estrogens (Diethylstilbestrol, Estriol)

PPA MOI

treatment of urinary incontinence due to urethral sphincter hypotonus