Adrenergic and Cholinergic Drugs Flashcards
Function of the Autonomic Nervous System
Responsible for controlling involuntary body functions: BP, digestion, elimination, thermoregulation
What are the two parts of the ANS?
- sympathetic nervous system
- parasympathetic nervous system
What does sympathetic innervation cause?
-increase in CO (increased HR and heart contractility)
-decreased visceral blood flow (to allow blood flow to skeletal mm)
-peripheral vasoconstriction
-increased cellular metabolism
-bronchial relaxation (decreased airway resistance)
-increases release of epinephrine and NE (fight or flight) = increases cardiac function
What does parasympathetic innervation cause?
-slows HR and heart contractility
-increases intestinal digestion and absorption
-bronchial constriction (increased airway resistance)
-peripheral vasodilation
What are the two neurotransmitters involved in the ANS?
- Acetylcholine- cholinergic
- Norepinephrine- adrenergic
What are the two categories of Cholinergic Receptors?
- Nicotinic
- Muscarinic
**both bind with acetylcholine, but they have different affinities
What are the 5 categories of Adrenergic Receptors?
- Alpha-1: found in smooth mm
- Alpha-2: decreases release of NE
- Beta-1: found in heart and kidneys
- Beta-2: found in smooth mm, bronchioles, uterus, and bladder
5: Beta-3: found in adipose tissue, heart, and bladder
What do drugs within the ANS work?
They will either stimulate or block a specific subtype of cholinergic or adrenergic receptors
What is the purpose of Cholinergic Drugs?
To alter the response of many different tissues to parasympathetic control by affecting the activity at cholinergic synapses
What are the different types of Cholinergic Stimulants?
- Direct acting stimulants: binds to cholinergic receptors to activate it
- Indirect acting stimulants: increase activity at cholinergic synapses by inhibiting the acetylcholinesterase enzyme
What does acetylcholinesterase do?
It is an enzyme that destroys acetylcholine- the purpose of indirect acting cholinergic stimulants is to inhibit this enzyme so it will allow more acetylcholine to remain at the synapse
What are cholinergic stimulants used for?
- Alzheimer Disease
- GI and bladder issues
- Glaucoma
- Myasthenia Gravis
- Neuromuscular blockage
Adverse effects of Cholinergic stimulants
-GI distress
-increased salivation
-bronchoconstriction
-bradycardia
-difficulty visual accommodation
-increased sweating
What is the purpose of Anticholinergic Drugs?
To diminish the effects to cholinergic stimulation
What are the two categories of anticholinergic drugs?
- Antimuscarinic drugs
- Antinicotinic drugs
Uses of Antinicotinic Drugs
-very specific for nicotonic receptors in the autonomic gangila
-used to treat HTN and blocks the skeletal neuromuscular junction
-used with anesthesia
Uses of Antimuscarinic Drugs
-Primarily used for GI disorders
-maybe used for PD
-Cardiovascular system (treats bradycardia)
-Motion sickness
-Preoperative medications (decreases respiratory secretions
-Urinary Tracts (alleviate urinary frequency and incontinence)
-Respiratory Tract (vasoconstriction)
-Eyes (pupil dilation)
**more commonly used than antinicotinic drugs
Side effects of Anticholinergic drugs
-dry mouth
-blurred vision
-urinary retention
-constipation
-tachycardia
How do Adrenergic Drugs?
To stimulate activity in the tissues that are affected by epinephrine and NE or to inhibit activity in the tissues
Adrenergic Stimulants/Agonists
Stimulate sympathetic nervous system responses
Other names for adrenergic agonists and adrenergic antagonists
-Adrenergic agonists: sympathomimetics
-Adrenergic Antagonists: sympatholytics
What disorders do Adrenergic Drugs treat?
-common cold
-HTN
-angina
-asthma
What are the different Adrenergic Receptors?
- Alpha:
-Alpha-1
-Alpha-2 - Beta:
-Beta-1
-Beta-2
-Beta-3
Which Adrenergic drugs can bind to which adrenergic receptors?
-some drugs only bind to one receptor subtype (very specific)
-some drugs will bind to either all alpha receptors or all beta receptors
-some drugs will bind to all alpha and beta receptors (not specific at all)
Location & Action of Alpha-1 Selective Agonist receptors
-receptors located primarily in smooth muscle
-causes smooth muscle contraction and vasoconstriction
What are Alpha-1 Selective Agonists used for?
-hypotension
-nasal congestion
-decreases HR during supraventricular tachycardia
Side effects of Alpha-1 selective agonists?
-increased BP
-HA
-decreased HR
-chest pain
-difficulty breathing
-nervousness
Location of Alpha-2 Selective Agonist Receptors?
-receptors located primarily at CNS synapses: brain and SC
Uses and side effects of alpha-2 selective agonists
Treats:
-hypertension
-spasticity
Side effects:
-dizziness
-drowsiness
-dry mouth
-difficulty breathing
-slow HR
-fainting (indicates toxicity or overdose)
Location and Action of Beta-1 selective agonist receptors
-receptors located on the myocardium
-stimulation causes increased HR and increased force of myocardial contraction
Uses of Beta-1 selective agonists
-increases cardiac output in emergency situations
-used for short term management of CHF
Side effects of beta-1 selective agonists
-chest pain
-cardiac arrhythmias
-SOB
-difficulty breathing
Location and action of beta-2 selective agonist receptors
-receptors located on bronchiole smooth muscle
-causes bronchiole relaxation and dilation
Uses of beta-2 selective agonists
Treats spasms and constriction associated with asthma, bronchitis, and emphysema
Side effects of Beta-2 selective agonists
-nervousness
-restlessness
-trembling
What are drugs with mixed alpha and beta agonist activity?
Drugs that can stimulate both alpha and beta receptors and mostly cause nervous system excitability
Examples: epinephrine and ephedrine
Side effects of drugs with mixed alpha and beta agonist activity
-restlessness
-anxiety
-HTN
-arrhythmias
How do Adrenergic Antagonists work?
They bind to adrenergic receptors and block them instead of activating them
-referred to as sympatholytic drugs since they block receptors that would normally cause sympathetic responses
**either alpha antagonists or beta antagonists
Alpha Antagonists Action and Use
Reduces peripheral vascular tone or causes vasodilation by blocking receptors on vascular smooth muscle that normally causes vasoconstriction
-used to treat HTN by decreasing peripheral vascular resistance
Side effects of Alpha Antagonists
Reflex tachycardia:
-when BP drops, the body compensates by increasing cardiac output and increasing HR
-orthostatic hypotension (after drug is first initiated)
Beta Antagonists Action and Uses
-binds to beta-1 receptors located on the heart
-causes the force of contractions and HR to decrease since receptors have been blocked
-treats HTN, arrhythmias, angina, s/p MI, and CHF
**beta-blockers
What is it called when beta-blockers only bind to beta-1 receptors?
cardioselective
What happens if beta-blockers are not selective to beta-1 receptors?
Then those beta antagonists will bind to both beta-1 and beta-2 receptors which will also cause bronchoconstriction and smooth muscle contractions
Beta Blocker Side Effects
-significant airway resistance in those with respiratory problems if they use a non-selective beta-blocker
-excessive depression of cardiac function
-orthostatic hypotension
-depression, lethargy, and sleep disorders
-blunted HR response to exercise
