Week 4 ~ Autonomic Nervous System Flashcards
What are two other names for Adrenergic Drugs?
Adrenergic Agonists
Sympathomimetics
What neurotransmitters does Adrenergic Drugs mimic?
Norepinephrine
Epinephrine
Dopamine
What are Adrenergic Receptors and what are the 3 receptors called?
Located throughout the body and are receptors for the sympathetic neurotransmitters
- A-Adrenergic Receptors
- B-Adrenergic Receptors
- Dopaminergic Receptors (For Dopamine Only)
What are the A-Adrenergic Agonist Receptors Responses?
- Vasoconstriction
- CNS stipulations
- Divided into a1 and a2 receptors
- Differentiated by their location on nerves
Where is the A1 Adrenergic Receptors located?
On the post synaptic effector cells
Where are the A2 Adrenergic Receptors located?
On pre-synaptic nerve terminals. Control the release of neurotransmitters
Functions of B-Adrenergic Receptors?
~Bronchial, GI and Uterine smooth muscle relaxation
~ Glycogenolysis
~Cardiac Stimulation
Location of B-Adrenergic Receptors?
All are located on postsynaptic effector cells
Where are B1 Adrenergic receptors located?
Primarily in the heart
Where are B2 Adrenergic Receptors located?
In smooth muscle of the bronchioles, arterioles, and visceral organs
What are the functions of Dopaminergic Receptors?
Stimulated by dopamine and cause dilation of the following blood vessels to increase blood flow:
Renal
Mesenteric
Coronary
Cerebral
What’s the receptor and response for receptor for Blood Vessels?
A1 and B2 —–> Constriction and dilation
What’s the receptor and response for cardiac muscle?
B1 —-> Increased contractility
What’s the Receptor and Response for Atrioventricular Node?
B1 —-> Increased Heart Rate
What’s the Receptor and Response for Sinoatrial Node?
B1 —-> Increased Heart Rate
What’s the Receptor and Response for Bronchial Muscles?
B2 —-> Dilation
What’s the Receptor and Response for Liver?
B2 —-> Glycogenolysis
What’s the Receptor and Response for Pupils?
A1 —–> Dilation
What are Catecholamines?
Substances that produce a sympathomimetic response
What are the Endogenous Catecholamines?
Epinephrine
Norepinephrine
Dopamine
What are the Synthetic Catecholamines?
Dobutamine
Phenylephrine
What are the 3 mechanism of actions of Sympathomimetics?
- Direct Acting
- Indirect Acting
- Mixed Acting
How do Direct-Acting Sympathomimetics work?
Binds directly to the receptor and causes a physiological response
How to Indirect-Acting Sympathomimetics work?
Cause the release of Catecholamine from storage sites (Vesicles) in the nerve endings. the Catecholamine then binds to the receptors and causes a physiological response
How does Mixed-Acting Sympathomimetics work?
Directly stimulates the receptor by binding to it and indirectly stimulates the receptor by causing the release of stored neurotransmitters from the vesicles in the nerve endings.
Actions of A-Adrenergic Receptors?
~ Vasoconstriction of blood vessels
~ Relaxation of GI smooth muscles
~ Contraction of the uterus and bladder
~ Male Ejaculation
~ Decreased insulin release
~ Contraction of the ciliary muscles of the eye (Dilated pupils)
Actions of B1 Adrenergic Receptors?
~ Affect the myocardium, AV node and SA node
~Increased force of heart contraction (+ve inotropic effect)
~Increased heart rate (+ve chronotropic effect)
~Increased conduction through the AV node (+ve dromotropic effect)
Actions of B2 Adrenergic Receptors?
~Bronchodilation (Relaxation of the bronchi)
~Uterine Relaxation
~ Glycogenolysis in the liver
~Increased renin secretion in the kidneys
What are the 6 B2-Adrenergic Drugs?
- Ephedrine
- Epinephrine
- Formoterol
- Salbutamol
- Salmeterol Xinafoate
- Terbutaline
Adverse Effects of A-Adrenergic?
~CNS: headache, restlessness, insomnia, euphoria
~Cardiovascular: Palpitations, tachycardia, vasoconstriction, HTN
~ Loss of appetite, dry mouth, nausea, vomiting
B-Adrenergic Adverse Effects?
~ CNS: mild tremors, headache, dizziness, nervousness
~ Cardiovascular: Increased heart rate, palpitations, fluctuations in
Blood pressure
~Sweating, nausea, vomiting, muscle cramps
B-Adrenergic Interactions?
Thyroid Preparations
Anti hypertensives
Anesthetic Drugs
Tricyclic Antidepressants
MAOIs
Antihistamines
What are Adrenergic Blockers?
Bind to Adrenergic receptors but inhibit or block stimulation of the sympathetic nervous system
*Include A-Blockers and B-Blockers
What are Adrenergic Blockers also known as?
Adrenergic Antagonists
Sympatholytics
A-Blockers
B-Blockers
A-B-Blockers
What’s another name for Adrenergic A-Blockers?
Ergot Alkaloids
Ergot Alkaloid Indications
~Constrict dilated arterioles in the brain
~Migraines
~ Stimulate uterine contractions (oxytocics) to control postpartum
Bleeding
~Treat Hypertension, especially in patients with Pheochromocytoma
~Benign prostatic hyperplasia, decrease resistance to urinary outflow
Common A-Blockers…
- Phentolamine Mesylate
- Prazosin Hydrochloride
- Alfuzosin Hydrochloride
- Doxazosin Mesylate
- Terazosin Hydrochloride
What does Phentolamine do?
*Rogitine
Restores blood flow and prevents tissue necrosis
Contraindications of A-Blockers?
Drug Allergy
Peripheral Vascular Disease
Liver and Kidney Disease
Coronary Artery Disease
Peptic Ulcer
Sepsis
A-Blocker Cardiovascular Adverse Effects?
Palpitations
Orthodontic Hypotension
Tachycardia
Edema
Dysrhythmias
Chest Pain
T
CNS A-Blocker Adverse Effects?
Dizziness
Headache
Drowsiness
Anxiety
Depression
GI A-Blocker Adverse Effects?
Nausea
Vomiting
Diarrhea
Constipation
Abdominal pain
What are Adrenergic Drugs?
Drugs that stimulate the sympathetic nervous system (SNS)
What do B-Blockers do?
Block stimulation of B receptors in SNS
Compete with norepinephrine and epinephrine
Include selective and non-selective B-Blockers
What do Non-Selective B-Blockers block?
Both B1 and B2 Receptors!
B1 Receptor location?
Located primarily in the heart and are called —->
Cardioselective B-Blockers
Where are B2 Receptors located?
Primarily on smooth muscles of bronchioles and blood vessels
Mechanism of action for Cardioselective Blockers?
~Reduces SNS stimulation of the heart
~Decreases heart rate
~ Slows conduction rate through the AV node
~Deceases myocardial contractility thus reducing myocardial oxygen
Demand
Nonselective B-Blocker Mechanism of Action?
~Same effects on the heart
~Constriction of bronchioles
~Vasoconstriction of blood vessels
B-Blocker Indications?
Antiangina —> decreases demand for myocardial oxygen
Cardio protective —> inhibits stimulation from Catecholamines
Antihypertensive
Migraines
Glaucoma –> topical use*
B-Blocker Contraindications?
Drug allergies
Uncompensated heart failure
Heart block
Cardiogenic shock
Bradycardia
Pregnancy
Severe pulmonary disease
B-Blocker interactions with other drugs?
- Antacids —-> decrease B-Blocker effects
- Anticholinergics —> decrease B-Blocker effects
- Anti diuretics —> additive hypotensive effects
Blood B-Blocker Adverse Effects?
Agranulocytosis
Thrombocytopenia
Cardiovascular/Peripheral B-Blocker Adverse Effects?
AV block
Heart Failure
Bradycardia
Vascular insufficiency
CNS B-Blocker Adverse Effects?
Dizziness
Mental Depression
Lethargy
Hallucinations
3 Non-Selective B-Blocker Drugs?
- Labetalol
- Propranolol Hydrochloride
- Sotalol Hydrochloride
4 Cardioselective B-Blocker Drugs?
- Acebutolol Hydrochloride
- Atenolol
- Esmolol Hydrochloride
- Metoprolol Tartrate
What are Cholinergic Drugs?
Drugs that stimulate the parasympathetic nervous system
What are Cholinergic Drugs also known as?
Cholinergic Agonists or Parasympathomimetics
What are the 2 types of Cholinergic Receptors?
- Nicotinic Receptors
2. Muscarinic Receptors
Where are Nicotinic Receptors located?
Ganglia of both the PSNS and SNS
Where are Muscarinic Receptors Located?
Postsynaptically in the effector organs of the PSNS such as:
Smooth muscle
Cardiac Muscle
Glands
What is Alzheimer’s Disease?
Most common form of dementia in Canada
Progressive and degenerative disease
Impairment of memory, judgement, language, personality
*Brain tissue shrinks as the disease progesses
Alzheimer’s Etiolgy
Genetic
Environmental
Lifestyle
Cholinergic Drug Mechanism of Action
- Direct Acting —> bind to Cholinergic receptors and activate
- Indirect Acting —-> inhibit the enzyme Cholinesterase
Which breaks down ACh allowing more
ACh being available at the receptors
2 Types of Indirect- Acting Cholinesterase Inhibitors
Reversible: Bind to Cholinesterase for a period of minutes/hours
Irreversible: Bind to Cholinesterase and form a permanent covalent
Bond
Cholinergic Drug Effects on the Intestine and Bladder?
Increase gastric secretions
Increase Gastrointestinal motility
Increased urinary frequency
What areas of the body does Cholinergic Drugs effect?
- Intestines and Bladder
- Pupils
- Cardiovascular
- Respiratory
Cholinergic Drug effects on the pupils?
Constriction (Miosis)
Reduce Intraocular pressure
Cholinergic Drug effects on the cardiovascular system?
Decreased heart rate
Vasodilation
Cholinergic Drug effects on the Respiratory System?
Bronchial Constriction, narrowed airways
Direct-Acting Cholinergic Drugs Indications?
*Poorly absorbed from the GIT
Reduce Intraocular pressure
Useful for glaucoma and Intraocular surgery
Direct-Acting Cholinergic Drugs for Glaucoma?
- Acetylcholine
- Carbachol
- Pilocarpine
What’s a Direct Acting Cholinergic Drug that’s absorbed in the GIT?
Bethanechol
What does Bethanechol do?
Increases tone and motility of the bladder and GI tract
Relaxes sphincters in bladder and GI tract, allowing them to empty
2 Indirect-Acting Cholinergic Drugs used as an antidote?
Neostigmine
Pyridostigmine
Indirect Acting Cholinergic Drug Indications?
Cause skeletal muscle contractions
Diagnosis and treatment of Myasthenia Gravis
Reverse neuromuscular blocking drugs
Reverse Anticholinergic Poisoning (Antidote)
What does Donepezil do?
An indirect acting Cholinergic drug that increases concentration of ACh in the pain and improve Cholinergic effects
What drug is used to treat or slow progression of Alzheimer’s Disease?
Donepezil
Cholinergic Drug Contraindications
Drug allergy
GI or GU tract obstruction (require surgery)
Bradycardia
Hyperthyroidism
Epilepsy
Hypotension
Parkinson’s Disease
Cholinergic Drug Adverse Effects?
Cardiovascular: Bradycardia, hypotension
CNS: Headache, dizziness, convulsions
GI: abdominal cramps, nausea/vomiting, increased secretions
Respiratory: Increased bronchial secretions, bronchospasms
Lacrimation, sweating, salivation, loss of binocular accommodation
Cholinergic Drug Interactions
Anticholinergics
Antihistamines
Sympathomimetics
*Antagonize Cholinergic drugs resulting in decreased responses
What are Cholinergic -Blocking Drugs?
Drugs that block or inhibit the actions of acetylcholine (ACh) in the parasympathetic nervous system
Also known as Anti -cholinergics
Cholinergic-Blocking Drug Mechanism of Action
- Competitive Antagonists: Compete with ACh
- Block ACh at the Muscarinic receptors in the PSNS
As a result ACh is unable to bind to the receptor site
*Once these drugs bind to receptors, they inhibit nerve transmission at these receptors
Natural Cholinergic-Blocking Drugs
Atropine
Belladonna
Hyoscyamine
Scopolamine
Cholinergic-Blocking Drug Effects
Cardiovascular:
- ---> Small doses decrease heart rate
- ---> Large doses increase heart rate
CNS:
- ---> small doses decrease muscle rigidity and tremors - ---> large doses cause drowsiness, disorientation
Eye: Dilated pupils
GI: Relax smooth muscle tone of GI tract and decrease intestinal
And gastric secretions
- Decreased bronchial secretions, salivation, sweating
- Increased constriction of internal sphincter
- Dilated bronchial airways
Cholinergic-Blocking Drug Indications
CNS: Decreased muscle rigidity and muscle tremors used
In Parkinson’s disease
Cardiovascular: Low doses slow the heart rate
High dosses block inhibitory vagal effects and
Results in increased heart rate
Respiratory System:
Bronchodilation—> chronic bronchitis, COPD, Asthma
Incontinence
IBS
Cholinergic Blocking Drug Contradictions
Drug Allergy
Narrow Angle Glaucoma
Acute Asthma
Myasthenia Gravis
Acute cardiovascular instability
GI or GU tract obstruction
Cholinergic-Blocking Drug Adverse Effects
Cardiovascular: Increased heart rate
CNS: excitation, irritability, delirium, disorientation, hallucinations
Eye: Dilated pupils, decreased visual accommodation
GI: Decreased gastric secretions, decreased motility
Cholinergic-Blocking Drug Interactions
Antihistamines
Monoamine Oxidase Inhibitors (MAOIs)
When given with Cholinergic-blocking drugs, these cause additive Cholinergic effects
What’s Parkinson’s Disease?
A chronic, progressive, degenerative disorder
Affects the dopamine-producing neurons in the brain
What 2 neurotransmitters cause Parkinson’s when they become imbalanced?
Dopamine
Acetylcholine (ACh)
Parkinson’s Disease Symptoms
Rigidity
Tremor
Postural Instablity
Bradykinesia
What is Levodopa Therapy?
Levodopa is a precursor of dopamine
The blood brain barrier doesn’t allow dopamine to enter but it allows Levodopa to enter
As Parkinson’s progresses it becomes more and more difficult to control with levodopa
Other Drug Therapies for Parkinson’s?
- Anticholinergic Drug
—> Block the effects of ACh
—> Used to treat tremors and muscle rigidity
(Two symptoms caused by excessive Cholinergic activity) - Antihistamines
- Dopamine Receptor Agonist (Direct Acting)
Parkinson’s disease Anti-Cholinergic Drug?
Benztropine
Parkinson’s Disease Anti-Histamine Drug Name?
Diphenhydramine
Parkinson’s Disease Dopamine Receptor Agonist Drugs?
Levodopa
Bromocriptine
Levodopa - Carbidopa
3 Indirect Acting Dopamine Receptor Agonists for Parkinson’s Disease?
- Selegiline: MAO-B Inhibitor (Monoamine Oxidase B)
- Entacapone: COMT Inhibitor (Catechol Ortho-methyl transferase)
- Amatadine: Symmetrel
Selegiline Indications?
Used in combination with Levodopa or Levodopa-Carbidopa
Used when a patient’s response to Levodopa is fluctuating
Adverse Effects of Selegiline?
Nausea Lightheaded mess Dizziness Abdominal Pain Insomnia Confusion Dry Mouth
Three Types of Dopaminergic Therapy?
- Replacement
- Direct-Acting/Replacement
- Indirect-Acting - Amantadine
* Adverse effects vary according to dose*
What is Anticholinergic Therapy?
ACh accumulates because of the imbalance of dopamine
Overstimulation of the Cholinergic excitatory causes:
Muscle Tremors and Muscle Rigidity
Cogwheel Rigidity
Pill-Rolling movement of fingers and head bobbing while at rest
In Parkinson’s it causes smooth muscle relaxation, reduces muscle riding its and akinesia
Anticholinergic Therapy Adverse Effects?
Drowsiness, confusion, disorientation
Constipation, nausea, vomiting
Urinary Retention, pain on urination
Blurred vision, dilated pupils, dry skin
Decreased salvation, dry mouth
Anticholinergic Therapy Interactions?
~Enhanced CNS depressant effects with:
alcohol CNS depressants Amantadine (Symmetrel) Antihistamines Tricyclic Antidepressants Phenothiazines
Reduced absorption and decreased therapeutic affect with antacids
