Module 2 Flashcards
Autonomic Nervous System Drugs
Nervous Systems consist of two main?
Central Nervous system and Peripheral Nervous System
CNS
Central Nervous System - Brain and Spinal corde
PNS
Peripheral Nervous System - Nerves outside CNS
Within the PNS there is Efferent Division and Afferent Division. What is the difference between these nerves?
Efferent Division -signals FROM brain/spinal cord
Afferent Division- signals TO brain/spinal cord
ANS
Autonomic Nervous System: Involuntary- acts largely unconsciously and regulates bodily functions such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal.
SNS
Somatic nervous system: voluntary portion of the peripheral nervous system -body movements via skeletal muscles. Consists of Efferent and Afferent signals
ANS is made up of :
Sympathetic-
Parasympathetic-
- Fight-or flight
- rest and digest
How Nerves Transmit Signals
When receptors filled, signals transmitted down neuron after which process repeats itself when signal jumps from nerve to nerves. Receptors travel over the synaptic cleft to adjacent nerve endings.
Neurotransmitter acetylcholine (ACH)
released from nerve ending into synaptic cleft(space between nerves). Function is to carry signals from motor neurons to the body’s skeletal muscles.
After ACH travels across synaptic cleft they?
bind to receptors on adjacent neuron.
After signal transmitted, ACH broken down by?
enzyme acetylcholinesterse (ACE) and recycled back into nerve ending for use in next transmission called “re-uptake”
Cholinergic Drugs
para-sympathomimetic: Stimulate parasympathetic(rest and digest) action at muscarinic, nicotinic receptors. Various drugs that inhibit, enhance, or mimic the action of the neurotransmitter(ACH) of nerve impulses w/in PNS (contracts smooth muscles, dilates blood vessels, increase bodily secretions, and slows heart rate.
Acetylcholine
neurotransmitter affected. ACH are chemical messages in the brain. Carries signals from motor neurons to the body’s skeletal muscles.
Cholinergic agonist drugs
mimic action of acetylcholine
Anti-cholinesterases
inhibit acetylcholine destruction at receptor sites. BLOCK ACH
Cholinergic agonist drugs are used for:
- increase bladder tone
- treat GI distention (bloating and swelling in belly) and atony (loss of strength in a muscle)
- Reduce eye pressure in glaucoma.
Adverse Effects of Cholinergic agonist drugs
Cholinergic agonists bind PNS receptors ➡can produce adverse effect in any organ innervated(supplied) by parasympathetic nerves.
- nausea, vomiting
- cramps, diarrhea
- blurred vision
- decreased heart rate, low blood pressure
- shortness of breath
- urinary frequency
- increased salivation/sweating
anti-cholinesterase drugs (ACD) inhibit? Allowing?
acetyl-cholinesterase(ACE)
-ACH (acetylcholine) to accumulate in the synaptic cleft, prolonging its effect.
2 categories of Anti-cholinesterases drugs:
- Reversible
- Irreversible
- Short duration of action; minutes to hours
- long-lasting effects; days to weeks; used as toxic insecticies, pesticides, nerve gas.
what are Anti-Cholinesterase drugs used for?
Antidote:
- increase bladder, GI tone
- Decrease eye pressure in glaucoma
- Diagnose and promote muscle contraction in myasthenia gravis (weakness and rapid fatigue of muscles under voluntary control)
- treat dimentia
-cholinergic blocking drugs
Adverse Effects from Anti-cholinesterase drugs
increased astion of acetylcholine leading to
- Cardiac arrhythmias
- nausea, vomiting
- Diarrhea
- Shortness of breath, wheezing, tight chest
- Seizures, headache
- Anorexia
- Insomnia
- Pruritus
- Urinary frequency, noturia
Cholinergic blocking (anti-cholinergic) (cholinergic antagonist) drugs prevent?
acetycholine stimulating parasympathetic muscarinic receptors
Paradoxical effect
can stimulate or depress, depending on doasge (when the opposite happens instead of intended reaction. (pain meds causing pain)
Muscarine receptors
stimulated by muscarine (an alkaloid derived from mushrooms ) blocked by atropine, belladonna, hyoscyamine sulfate, scopolamine ( all antidotes for cholinergic and nati-cholinesterase drugs)
Atropine uses
Blocks cholinergic activity on eye➡ mydriasis (dilation of pupil), lasts - 4 hrs.
Anti-spasmodic in GI system
Cardiovascular
-Low dose: decreases cardiac rate (bradycardia)
-High dose: increases cardiac rate (tachycardia)
How Atropine works: Acetylcholine (ACH) stimulates ____ and ______ inhibiting ______➡heart rate ____Atropine competes with _____; low dose_____; high dose ______
sinoatrial (SA) and atrioventricular (AV) nodes, inhibiting conduction. Heart rate slows. Atropine competes with ACH. Low dose decreases heart rate; high dose increases heart rate.
Adverse Effects of Atropine use
cholinergic blocker adverse effects related to dosage; little difference between therapeutic and toxic dose
- dry mouth
- reduced bronchial secretions
- increased heart rate
- decreased sweating
Adrenergic (sympathomimetic) drugs
produce sympathetic effects at alpha, beta, dopamine receptors
Neurotransmitters affected by Adrenergic drugs
Norepinephrine, epinephrine, dopamine
2 types of Adrenergics:
-Catecholamines:
Synthetic Catecholamines have a-
-Non-catecholamines:
- produced by the sympathetic nervous system; not taken orally as destroyed by digestive enzymes; excitatory or inhibitory response (norepinephrine, epinephrine, dopamine)
- have shorter duration than natural (produced by body) catecholamines
-oral administration; longer duration of action
Catecholamines
-Excitatory response:
- Inhibitory response
- Potent inotrope
- Positive chronotropic effect
- Potent inotrope
-at alpha receptors (except for intestinal relaxation). Neuron that triggers a positive change in the membrane
- at beta receptors (except in heart cells)
- makes heart contractions more forceful
- causes heart to beat faster
Adrenergics
working on adrenaline (epinephrine)
Adrenergic Action
- Direct-acting
- Indirect -acting
- Dual-acting
- on target organ
- trigger neurotransmitter release
- works on target organ AND trigger neurotransmitter release
Adrenergics Receptors
- Alpha receptors
- Beta receptors
- Dopamine receptors
- mimic norepinephrine (NOR)
- mimic norepinephrine (NOR), epinephrine (EPI)
- mimic dopamine
Direct Acting Adrenergics
AD drug directly stimulates receptors without interaction with pre-synaptic neuron containing norepinephrine(no NOR is disturbed in presynaps). AD drug only connects to post-synaptic neuron
Indirect Acting Adrenergics
AD drug stimulates release of norepinephrine (NOR) from pre-synaptic neuron, which then does the binding. AD releases the bodies NOR and this is the binding agent only (NOR
Dual Acting Adrenergics
Adrenergic drug (AD) stimulates release of norepinephrine (NOR) and binds receptors. Both AD and NOR release and bind to post-synaptic neuron
How are Adrenergic drugs used?
- Increase low blood pressure
- Restore heart rhythm
- Improve breathing by dilating bronchioles
Adverse Effects of Catecholamine
restlessness, anxiety, dizziness, headache, palpitations, cardia arrhythmia, hypo-tension, hypertension and hypertensive crisis, stroke, angina, increased blood glucose levels, tissue necrosis (if IV)
Non-catecholamine adverse effects
headache, restlessness, anxiety or euphoria, irritability, trembling, drowsiness or insomnia, light-headedness, incoherence, seizures, hypertension or hypo-tension, palpitations, bradycardia or tachycardia, irregular heart rhythm, cardiac arrest, cerebral hemorrhage, tingling or coldness in arms or legs, pallor or flushing, angina
Adrenergic Blocking Drugs
Classification by site of action:
(Sympatholytic) block sympathetic impulses at alpha and beta receptors (NOR and EPI affected)
- alpha blockers
- beta blockers
Alpha blockers
- occupy receptors on blood vessel
- blood vessel wall relaxes➡ vessel dilates
- Dilated vessels= decreased resistance to blood flow
- decreases blood pressure
Alpha Blocker Problem OH
Orthostatic hypotension: drop in blood pressure changing position from lying down to standing up; due to redistribution of blood to dialated vessels in legs
Alpha blocker drugs are used to:
- decrease hkypertension
- Increase local blood flow
Alpha-adrenergic blocker adverse effects caused primarily by?
Symptoms?
dilation of blood vessels
- orthostatic hypotension or severe hypertension
- bradycardia(slow) or tachycardia(fast)
- edema
- difficultly breathing
- light-headedness
- flushing
- arrhythmia, angina(chest pain from lack of blood flow), heart attack
- spasm of blood vessels in breain
- shock-like state
Beta Blockers
Non-Selective:
2 types
Selective:
Occupy beta receptors blocking catecholamines (norepinephrine, epinephrine)
- Beta1 receptors: in heart; reduce stimulation
- Beta2 receptors: in bronchi, blood vessels, uterus; cause constriction
beta1 receptors
How is a beta blocker used?
- reduce blood pressure
- reduce heart rate
- decrease force of heart conractions
- contrict bronchioles
- contrict peripheral blood vessels
Adverse Effects of Beta-blockers
These are drug or dose dependent
- hypotension
- bradycardia, peripheral vascular insufficiency, atrioventricular block, heart failure
- fatigue
- bronchospasm
- diarrhea or constipation
- nausea, vomiting, abdominal discomfort, anorexia, flatulence
- rash
- fever with sore throat, spasm or larynx, respiratory distress (allergic response)
