ANS Pharmacology Flashcards
What is the role or preganglion and postganglionic neurons
preganglionic: release ACH
postganglionic: release norepinephrine or ACH at the effector organs
what is the role of the parasympathetic division?
Salivation
Lachrymation
Urination
Defecation
Usually active during relaxation or after a meal (BP, HR, RR low, GI activity high, constricted pupils)
what is the role of the sympathetic NS?
fight or flight, promotes adjustments during exercise or when threatened
Blood flow is shunted to skeletal muscles and heart, bronchioles dilate, and liver releases glucose
what receptors does ACH bind to?
1.Nicotinic receptors (Nn in ANS and Nm) in skeletal neuromuscular junction)
2. Muscarinic receptors
where are nicotinic receptors found? What is the effect of ACh at these receptors?
Motor end plates of skeletal muscle cells, ganglionic neurons, hormone cells of the adrenal medulla
ACH at nicotinic receptors is always stimulatory
where are muscarinic receptors found? What is the effect of ACh at these receptors?
All effector cells stimulated by postganglionic cholinergic fibers
ACh can be inhibitory or excitatory
Describe the location of muscarinic receptors
M1, M4, M5 = CNS
M2=heart
M3=smooth muscle
what is the use, purpose, target receptors, and adverse reactions of Bethanechol (direct acting cholinergic agonist)
Use: post op GI and urinary atony
Purpose: Increase tonicity in the detrusor muscle and stimulate gastric motility
Target receptor: Muscarinic
Adverse reactions: GI discomfort, urinary urgency, flushing, bronchial constriction, asthma attacks
what is the role of cholinergic agonists?
Parasympathomimetics that mimic the effect of ACh.
Direct: Mimic the activity of ACh at the cholinergic receptors
Indirect: inhibit the actions of acetylcholine esterase enzyme
what is the use, purpose, target receptors, and adverse reactions of Pilocarpine (direct acting cholinergic agonist)
Use: glaucoma
Purpose: decrease fluid in eye to decrease pressure
Target receptor: muscarinic
Adverse reaction: blurred vision, decreased night vision, eye irritation, headache, increased sweating and salivation
what is acetylcholinesterase (AchE) and acetylcholinesterase inhibitors?
Acetylcholinesterase (AchE) is an enzyme that breaks
down ACh in the postsynaptic membrane
Acetylcholinesterase (AchE) inhibitors: block the actions of AchE, and thus increase the
levels and duration of action of ACh
What are indirect-acting cholinergic agonists?
Referred to as cholinesterase inhibitors or anticholinesterase agents commonly used to increase endogenous acetylcholine levels
Alz: Donepezil, Rivastigmine
Myasthenia gravis: Physostigmine, Pyridostigmine
Glaucoma: Neostigmine, Ecothiapate
what are common adverse effects of cholinergic stimulants?
*GI Distress
*Increased Salivation
*Increased Lachrymation
*Bronchoconstriction
*Bradycardia
*Difficulty in visual accommodation
what is the common MOA of anti-cholinergic drugs?
Competitive antagonist at muscarinic receptors
What are common alpha-1-selective agonists?
*Phenylephrine: Decreases nasal congestion
*Pseudoephedrine: Decreases nasal congestion
*Oxymetazoline: Decreases nasal congestion and reduces redness of the eye
*Xylometazoline: Decreases nasal congestion
What are adverse effects of alpha-1-agonist?
increased BP, headache, and slow HR due to reflex bradycardia
what are common alpha-2-selective agonists and their adverse effects?
Clonidine: Antihypertensive agent
Methyldopa: Antihypertensive agent
Adverse Effects: Dizziness, Drowsiness, Dry mouth
what are common beta-1-selective agonists and their adverse effects?
Dobutamine: Increases the force of cardiac contraction(positive inotropic effect)
Dopamine: CHF
Adverse Effects: Chest pain, Cardiac arrhythmias, SOB
what are beta-2 agonists and their adverse effects?
Albuterol: Bronchodilation in patients with asthma
Salmeterol: Bronchodilation in patients with asthma
Terbutaline: Delay preterm labor (slow contractions of the
uterus)
Adverse Effects: Nervousness, Restlessness, trembling
what are drugs with mixed alpha and beta agonist activity? what are the adverse effects?
Amphetamines: To treat attention-deficit disorder in children as well as narcolepsy
Epinephrine: Anaphylactic shock
Norepinephrine: To treat hypotension during shock
Adverse Effects: CNS excitation, Anxiety,
,Hypertension, Arrhythmias
What are common alpha-1-selective antagonists?
-ozin
*Prazosin: Anti HTN
*Doxazosin: Anti HTN
*Alfuzosin: Treat urinary retention and symptoms of Benign prostatic hyperplasia
*Tamsulosin: Treat urinary retention and symptoms of Benign prostatic hyperplasia
*Phenoxybenzamine: To control blood pressure prior to and during the removal of a
pheochromocytoma (cancer of adrenal gland)
*Adverse Effects: Reflex tachycardia, Orthostatic hypotension, Dizziness
What are beta-1 selective antagonists?
Cardioselective (-olol)
*Atenolol: Treatment of HTN and chronic stable angina
*Bisoprolol: Treatment of HF
*Metoprolol: Treatment of HF
*Esmolol: Treatment of arrhythmias during surgery
what are the adverse effects of Beta-adrenergic- antagonists?
*Bronchoconstriction
*Increase in airway resistance (due to Beta-2 antagonism)
*Bradycardia (slow heart rate)
*Dizziness
*Depression
*Lethargy
What drugs are Beta 1 selective antagonists and what are their primary indications?
Metoprolol, Atenolol, Bisoprolol, Nebivolol, Acebutolol, Esmolol
Primary indication: HTN, angina, HF
