alpha1 agonist

Constriciton or contraction:

Causes pupillary mydriasis (along w/ anticholinergics) - b/c ciliary muscles constrict

Produces potent vasoconstriction

Ejaculation

Uterus contraction

Increases BP

Increased GI motility

Alpha2 agonist

Dilation or relaxation:

Causes central vasodilation

What does a Alpha antagonist do?

Blocks catecholamine at the receptor site & reverses the effect of the alpha adrenerigc activity

What is direct competition?  Are effects reversible or irreversible?

The alpha blocker displaces the norepi moleucules from teh alpha receptor sites

The site is then less responsive to the neurotransmitter norepi

Effects are reversible

What is alpha blockade noncompetition?  Are the effects reversible or irreversible?

Med binds withe the alpha-adrenergic receptor site

Bonding is covalent - irreversible

What are the uses of alpha blockers?

Relieve migraines:  constrict dilated arterioles in the brain

Relieve post-partum bleeding:  increase uterine contractions

HTN:  arterile & venous dilation

pheochromocytoma - reverses effects of catech secretion by tumor

extravasation of vasopressors - reverse vasoconstriciton & restore blood flow to constricted area

What are contraindications for alpha blockers?

allergy

Peripheral vascular disease (further constricts)

Hepatic & renal disease (further constricts)

Coronary artery disease

Sepsis

What are the adverse effects of alpha blockers?

Extension of the intended effects

CV:  Hypotension, rebound tachy, dysrhythmias, edema

CNS:  dizziness, drowsiness, depression, weakness, fatigue

GI:  N/V/C

What do beta blockers do?

What (tissue) are the most frequent targets of beta blockers

Surface of heart

Smooth muscle of lungs

Smooth muscle of blood vessels

What do alpaha agonist predominantly do?

Cause vasoconstriction and CNS stimulation

Where are alpha1 agonsit receptors located?

On post-synaptic effector cells = the tissue, muscle, or organ that nerve stimulates

Where are alpha 2 receptors located?

On the pre-synaptic nerve terminals = control the release of the neurotransmitters

Where are all Beta receptors located? Beta 1 specifically?  Beta2 specifically?

On post-synaptic effector cells

In the heart

Smooth muscle of the bronchioles, arterioles, visceral organs

What does a Beta agonsit response result in?

Bronchial, GI, & uterine smooth muscle relaxation

Glycogenolysis

Cardiac Stimulation

What does stimulation of dopaminergic receptors cause?

Dilation of vessels of the renal, mesenteric, coronary & cerebral arteries = increased blood flow to these tissues

How does an indirect acting adrenergic drug cause stimulation?

What does a mixed-acting sympathomimetic do?

It directly stimualtes the receptor by binding to it and causes the release of the neurotransmitter stored in the nerve endings

Define the following: 

inotropic

chronotropic

dromotropic

force of contraction of heart

heart rate

condution of impulses through AV node

What -tropic effects do Beta 1 adrenergics have?

+inotropic (force)

+chromotropic (HR)

+dromotropic  (conduction)

What effects do Beta 2 adrenergics have?

Relaxation of bronchi & uterus

increased glycogenolysis (increased BG)

increased in renin secretion (increased BP)

What adrenergic agsonst is helpful in treating resp conditions? Why?  What is an example?

Beta 2 selective adrenergics

they are predominantly attracted to beta 2 receptors on the bronchial, uterine & smooth muscles

albuterol

What adrenergic is helpful in treating nasal congestion? Why?  Example?

alpha1 adrenergics

they cause constriction of dialted arterioles & reduction of nasal blood flow

pseudoephedrine (Afrin)

What does vasoactive or "pressor" effect mean?

It means that receptors are activated that produce effects that help to support cardiac function during cardiac shock or failure.

If given w/ these drugs, the result will be heightened effects (3)

anti-depressants

antihistamines

thyroid preparations

What key drug is a selective Beta 2 agonist?  What does this mean?

Albuterol

It causes bronchodilation w/o cardiac stimulation

What key drug is a endogenous catecholamine w/ mixed alpha & beta effects?  What does it cause?

Epinephrine

Vasoconstriction (increased BP)

+ino, dromo, chrono

Bronchodilation

When is epi contraindicated?

CAD, HTN - increases BP & heart activity

Narrow-angle glaucoma

Labor - slows uterine contractions down

local anesthesia of fingers, toes, penis or noes -causes vasoconstriciton

What key drug is a mixed alpha and beta agonist (not naturally occur)?  What does it do?

pseudoephedrine (Afrin)

Decongests the nose by causing vasoconstriction in the nasal mucosa thereby decreasing secretions

What key drug is a Beta1 agonist?  What does it cause?

dobutamine (Dobutrex)

+ ino, chrono, dromo effects

so used for HF & shock

What key drug is an alpha antagonist?  What does it do?

phentolamine (Regitine)

reduces peripheral vascular resistance by vasodilating- reduces BP

Also used to counter extravasation of adrenergic meds b/c potent vasodilator

What key drug is a alpha1 antagonist?  What does it do?

prazosin (Minipress)

blocks in the arterioles, venules & smooth muscles of bladder & prostrate - treats HTN & BPH

What key drug is a Beta1 blocker?  What does it do?

metoprolol (Lopressor)

it competes w/ epi & norepi in the heart & reduces activity of the heart - treats HTN and early or late MI (catecholamines are secreted when myocard damaged)

What key drug is a Beta blocker?  What does it do?

propranolol (Inderal)

reduces cardiac stimulation - decreases HR (ino) & contractility (chrono); slows conduction (dromo) = treats angina, HTN,post-MI,

Tachydysrhytmias in conjunction w/ dig toxicity, aortic stenosis, Grave's disease, pheochromocytoma

Migranes & tremors - vasoconstriction of cerebral arterioles

What patients are non-selec beta blockers contraindicated in? Why?

those w/ compromosed lung function (esp. asthmatics)

b/c it causes vasoconstriction of the bronchioles

Why should diabetics be careful when taking beta blockers?

beta blockers impair the process of glycogenolysis (making glucose from glycogen when BG is low) & they mask the effects of hypoglycemia (slow heart activity & bronchiole constriction)

What do cholinergic receptors bind to?

acetylcholine

What does SLUDGE stand for?  Refering to?

Salivation

Lacrimation

Urinary incontinence

Diarrhea

GI cramps

Emesis

cholinergic poisoning

What is a direct acting key drug used primarily in bladder stimulation?

bethanechol (Ureocholine)

indications:  non-obstructive urinary retention

What indirect acting key cholinergic agonist is used to treat alzheimer's disease?  How?

donepezil (Aricept)

-increases ACh by blocking its breakdown by anticholinesterase in the brain

What indirect acting cholinergic agonist key drug treats myasthenia gravis?  How?

physostigmine (Antilirium)

-inhibits ACh breakdown by enzyme - improves muscle strength (myasthenia gravis destroys ACh receptors)

Why do anticholinergics have the same effects as adrenergics?

The PSNS is blocked (ACh receptors) & SNS is allowed to dominate

What is the antedote for cholinergic toxcicity?

What does the cholinergic antagonist key drug atropine do in children?

therapeutic anticholinergic effect, counters bradycardia, controls secretions

-increases HR & causes bronchodilation

This cholinergic antagonist key drug is used to treat IBS? Why?

dicyclomine (Bentyl)

antagonize muscarinic receptors that causes gastric secretions, contraction of smooth muscle, increased GI motility & peristalsis

This anticholinergic key drug is used to treat overacitve bladder?  Why?

tolterodine (Detrol)

blocks muscarinic receptors in the bladder - resulting in relaxed detrusor muscle (constricts to pee) & increase constriction of internal sphincter (involuntary)