Peripheral Nervous System & Diuretics

parasympathetic nervous system (PSNS)

housekeeping system - GI, bladder, eyes

decreased HR

increased gastric secretion

sympathetic nervous system (SNS)

fight or flight

increased HR, vasoconstriction, bronchodilation

peripheral nervous system (PNS)

divides into PSNS and SNS

adrenergic

epinephrine & norepinephrine

receptors: alpha1, alpha2, beta1, beta2, beta3, dopamine

cholinergic

acetylcholine

receptors: nictonicN, nicotinicM, muscarinic

acetylcholine life cycle

ACh = cholinę + acetylcoenzyme A

stored then destroyed by acetylcholinesterase --> uptake of choline

norepinephrine life cycle

precursors --> vesicles --> reuptake --> converted to epinephrine

dopamine receptor

adrenergic (epi & NE)

muscarinic

cholinergic (ACh)

NicotinicN

cholinergic (ACh)

nicotinicM

cholinergic (ACh)

alpha1 and alpha2

adrenergic (Epi & NE)

beta1 and beta2

adrenergic (Epi & NE)

muscarinic agonist

drugs that activate acetylcholine & stimulate PSNS

muscarinic antagonist

medications that block acetylcholine from binding to muscarinic receptors

bethanechol

muscarinic agonist

used for relieving urinary retention

side effects: hypotension, excessive salivation & gastric acid secretion, bronchoconstriction in asthmatics

atropine

muscarinic antagonist

Uses: preanesthetic med, eye disorders, bradycardia, decreased intestinal motility, and muscarinic agonist poisoning

side effects: dry mouth, blurred vision, elevation of eye pressure, constipation, tachycardia

Physostigmine

muscarinic antagonist

inhibitor of acetylcholinesterase --> leads to increased ACh within the body

cholinesterase inhibitors

prevent degradation of ACh by acetylcholinesterase

reversible and irreversible

Myasthenia Gravis

fluctuating muscle weakness and rapid fatigue

symptoms: drooping eyelids, difficulty swallowing, muscle weakness, breathing difficulties

autoimmune-antibodies against nicotinicM receptors

neuromuscular blocking agents

blocks nicotinicM --> results in muscle relaxation

ganglionic blocking agents

blocks nicotinicN & largery replaced

lacks selectivity & infrequently used

adrenergic agonists

medications that trigger body's adrengergic receptors to copy the body's natural fight or flight response of the nervous system

catecholamines

epinephrine, norepinephrine, dopamine, isoproterenol, dobutamine

have a brief duration of action

cannot cross BBB

not given orally

non-catecholamines

have an amine group

ephedrine, phenylephrine, terbutaline

longer duration of action

penetrates BBB

can be given orally

epinehprine (Adrenalin, EpiPen)

receptors: alpha1, alpha2, beta1, beta2

used for: anaphylactic shock, delay absorption of anesthetics, hemostasis, asthma

Side effects: hypertensive crisis, dysrhythmias, angina

norepinephrine (Levophed)

receptors: alpha1, alpha2, beta1

used for: hypotension & cardiac arrest

side effects: same as epi

isoproterenol (Isuprel)

beta1, beta2

used for: AV heart block, asthma, bronchospasm

side effects: dysrhythmias, angina, and hyperglycemia

dopamine (intropin)

dopamine, beta1, alpha1

used for: shock, heart failure, acute renal failure

side effects: tachycardia, dysrhythmias, angina, necrosis

ephedrine

alpha1, alpha2, beta1, beta2

mixed drug (direct activation of alpha/beta & indirect activation by releasing NE)

used for nasal congestion, narcolepsy

side effects: same as epi, insomnia

terbutaline (Brethine)

beta2

used for asthma, delay of preterm labor

side effects: tremors

phenylephrine

treats nasal congestion, raise BP by reducing blood flow

alpha-adrenergic antagonists

used for hypertension, reversal of alpha1 toxicity, benign prostatic hyperplasia, Raynaud's disease

side effects: orthostatic hypotension, reflex tachycardia, nasal congestion

prazosin (Minipress)

alpha1

used for hypertension, benign prostatic hyperplasia

side effects: orthostatic hypotension, reflex tachycardia, nasal congestion

Phentolamine (Regitine)

alpha1, alpha2

used for pheochromocytoma

side effects: orthostatic hypotension, reflex tachycardia, nasal congestion

beta-adrenergic antagonist

used for: angina pectoris, hypertension, dysrhythmias, MI, heart failure

side effects beta1: bradycardia, precipitation of HF, AV heart block

side effects beta2: bronchoconstriction, inhibits glycogenolysis

propranolol (Inderal)

beta1, beta2

used for hypertension, angina, MI

side effects: bradycardia, HF, CNS effects, bronchoconstriction

contraindications: diabetics, severe allergic reaction, HF, asthma, depression

drug interactions: calcium channel blockers, insulin

metoprolol (Lopressor)

beta1

used for hypertension, patients with asthma or diabetes & angina or MI

side effects: bradycardia, AV heartblock

contraindications: HF, sinus bradycardia

reserpine

mechanism of action: suppresses NE synthesis & displaces NE from vesicles

uses: hypertension

side effects: depression, bradycardia, orthostatic hypotension

Clonidine

mechanism of action: activates alpha2 receptors to decrease transmitter release

used for hypertension & severe pain

side effects: drowsiness, dry mouth, rebound hypertension

methyldopa

mechanism similar to clonidine except must be converted to methyline

used for hypertension

side effects: hemolytic anemia & liver toxicity

diuretics

increased output of urine

three applications: hypertension, mobilization of fluid, prevent renal failure

furosemide (Lasix)

blocks Na+ & Cl- reabsorption (K+)

reserved for rapid/massive mobilization --> pulmonary hypertension

adverse effects: dehydration --> headache/pain in chest, calves, or pelvis, hypotension, hypokalemia-digoxin toxicity, ototoxicity

hydrochlorothiazide

blocks Na+ & Cl- reabsorption (K+)

elevate uric acid & glucose

lower efficacy

adverse effects: dehydration --> headache/pain in chest, calves, or pelvis, hypotension, hypokalemia-digoxin toxicity

spironolactone (aldactone)

modest increase in urine production, decrease in K+ excretion

blocks aldosterone in distal nephron

adverse effects: hyperkalemia

triamterene (Dyrenium)

direct inhibitor of potassium/sodium exchange

adverse effects: hyperkalemia

mannitol (Osmitrol)

creates osmotic force as undergoes minimal reabsorption

intracranial pressure, intraocular pressure

adverse effects: edema

autonomic nervous system (ANS)

regulates HR

regulates secretory glands

regulates smooth muscles

shared between PSNS & SNS