ganglion blocking drugs
TRANSCRIPT
-
7/27/2019 Ganglion Blocking Drugs
1/13
-
7/27/2019 Ganglion Blocking Drugs
2/13
is a mass of nerve tissue
containing cell bodies ofneurons that is locatedoutside the central nervous
system.
-
7/27/2019 Ganglion Blocking Drugs
3/13
AUTONOMICGANGLIA LOCATIONSympathetic =>located near target
organs
=>consist of Celiac,
Hypogastric, Superiormesenteric and
Inferior mesenteric
Parasympathetic =>near target organsin the head (Ciliary,
Pterygopalatine,Submandibular andOtic)=>embedded in thewalls of target organsin the thorax,abdomen, and pelvis
-
7/27/2019 Ganglion Blocking Drugs
4/13
GANGLION-BLOCKING DRUGS
-
7/27/2019 Ganglion Blocking Drugs
5/13
Tetraethylammonium (TEA)
Hexamethonium
Mecamylamine
Trimethaphan
-
7/27/2019 Ganglion Blocking Drugs
6/13
absorption of quaternary ammonium (Hexamethomium,Tetraetylammonium) and sulfonium (Trimethaphan) from the
enteric tract is incomplete.
confined primarily to the extracellular space and are excretedmostly unchanged by the kidney.
MECAMYLAMINE:
=> a secondary amine, crosses both the blood brain,and placental barriers and well absorbed orally
=> concentrates in the liver and kidney,and excretedslowly in an unchanged form.
TRIMETHAPHAN: is inactive orally and is given by IV infusion.
-
7/27/2019 Ganglion Blocking Drugs
7/13
FIRST GROUP: characterized by
nicotine
stimulates ganglia andthen blocks them
causing a persistentdepolarization
Ex:
carbamoylcholinetetraethylammonium
SECOND GROUP: inhibit the postsynaptic
action of Ach nondepolarizing
blockade
Either:->by competing w/Ach for ganglionic
nicotinic receptor sites( Ex: Trimethaphan)->by blocking thechannel(Ex: Hexamethonium)
-
7/27/2019 Ganglion Blocking Drugs
8/13
SITE PREDOMINANT TONEEFFECT OF GANGLIONIC BLOCKADE
Arterioles Sympathetic (adrenergic) Vasodilation; increased peripheral bloodflow; hypotension
Veins Sympathetic (adrenergic) Dilation: peripheral pooling of blood;decreased venous return; decreasedcardiac output
Sweat glands Sympathetic (cholinergic) Anhidrosis (deficiency or absence ofperspiration)
-
7/27/2019 Ganglion Blocking Drugs
9/13
SITE PREDOMINANT TONE EFFECT OF GANGLIONIC BLOCKADE
Heart(S-A node)
Parasympathetic (cholinergic) Tachycardia
IrisParasympathetic (cholinergic) Mydriasis (dilation of the pupil)
Ciliary muscle
Parasympathetic (cholinergic) Cycloplegiafocus to far vision
Gastrointestinaltract
Parasympathetic (cholinergic) Reduced tone and motility; constipation;decreased gastric and pancreatic
secretions
Salivary glands Parasympathetic (cholinergic) Xerostomia (dry mouth )
-
7/27/2019 Ganglion Blocking Drugs
10/13
SITE PREDOMINANT TONE EFFECT OF GANGLIONIC BLOCKADE
Urinary bladder Parasympathetic (cholinergic)Urinary retention
Precipitate urinary retention in men
with prostatic hypoplasia.
Genital tract
Sympathetic (ejaculation) andparasympathetic (erection)
Decreased stimulation
-
7/27/2019 Ganglion Blocking Drugs
11/13
=> Many responses are undesirable effects that limit the therapeuticusefulness of these agents.
=>Are still important in pharmacological and physiological
research because of their ability to block autonomic ganglia.
MILD: Mydriasis
Dry mouth
Urinary hesistancy
Constipation Abdominal discomfort
Diarrhea
MORE SERIOUS: Hypotension Paralytic ileus Anginal pain
-
7/27/2019 Ganglion Blocking Drugs
12/13
MECAMYLAMINE (INVERSINE):
blocks central nicotinic receptor
reported effects: tremors, seizures and mentalconfusion
possible adjunct with the transdermal nicotinepatch to reduce nicotine craving in patients
attempting to quit smoking.
rarely used as an antihypertensive drugs
-
7/27/2019 Ganglion Blocking Drugs
13/13
TRIMETHAPHAN (ARFONAD):
is an extremely short-acting agent
used in the emergency treatment inhypertensive crisis due to direct vasodilatingproperties.
production of controlled hypotension incertain surgical procedures to reducebleeding.