Drug List Flashcards
Norepinephrine
sympathetic agonist: a1 = a2, b1>>b2: “pressor agent”
Effects on Heart:
- direct: positive inotropic and chronotropic via B1
- indirect: results in reflex bradycardia (blocked by atropine)
- net effect: slow, forceful HR
Effects on Blood Vessels:
- a1 mediated vasoconstriction, increased BP
Epinephrine: what is its effect on the heart? what is its effect on the blood vessels? What is its effect on smooth muscle?
- a1 = a2, b1 = b2
- sympathomimetic agonist
Has Major effects on HEART:
- chronotropic effect
- inotropic effect
- increased conduction in atria, A-V nodes and purkinge fibers
- the work of the heart is increased substantially and thus oxygen consumption is greatly increased (bad for people with MI’s)
At Blood Vessels of Skeletal Muscle: stimulates both a1-vasoconstriction and B2-vasodilation. Epi is more potent at B2 than a1, thus at low concentrations and vasodilation will predominate. However, at high concentrations (what is used in hospitals) a1 vasoconstriction predominates. Epi >>> NE at B2. Thus blood pressure will increase.
Smooth Muscle: results in Bronchial smooth muscle relaxation via B2 and opens the bronchial airways
Isoproterenol
- potent against all b receptors: no a effects
- sympathomimetic (agonists): synthetic catecholamine
Heart:
- results in B1 increased HR and force
Blood Vessels:
- B2 vasodilation in skeletal muscle and mesentary
- decreased diastolic BP, increased systolic BP - results in slight decrease to mean BP
phenylephrine (Neo-Synephrine)
a1 > a2 >>>>> b
a1-Selective Agonist: pressor agent
- results in vasoconstriction, increased peripheral resistance, increased BP resulting in reflex bradycardia (blocked by atropine)
Albuterol (Proventil, Ventolin)
B2>>B1>>>>>a
B2- selective agonist: effect on lung > heart (x10)
results in bronchodilation, and is used to treat bronchospasm in asthma
-side effects could result in muscle tremors and tachycardia due to B1 activation and reflex.
Dobutamine (Dobutrex)
B1-Selective Agonist
Clinically: mostly B1 effects: resulting in positive inotropic and some increase in HR. CO increases, little vascular effect
Clincal Uses: MI, CHF, Cardiogenic shock
(b1 > b2 >>a1)
Dopamine (Intropin): what is it used clinically for?
Dopamine Agonist
Used clinically for Cardiogenic Shock: heart able to pump as much blood as the body needs
Pharmacological effects:
- blood vessels (D1 receptors): vasodilates renal –> increased blood flow to kidney
- heart (B1 agonist): mild increase in rate and force of contraction
- blood vessels (a1 receptors): **high does causes vasoconstriction and increased BP **
(D1=D2>>b>>a)
Propranolol: pharmacological effects? contraindications?
- Nonselective B-Adrenergic Antagonist
- b1=b2>>>a
- Pharmacological effect on the heart:
- decreases heart rate and CO, decreases exercise tolerance
- decreases work of heart and O2 demand
- decreases AV nodal conduction and reduces infarct size to prevent sudden death
- Contraindications?
- Blocks sympathomimetic bronchodilation: do not use to treat people with asthma and COPD
- Blocks B receptor lipolysis and glycogenolysis. May mask signs of hypoglycemia and may potentiate in insulin-induced hypoglycemia in diabetics
Atenolol
b1-Selective B-adrenergic Antagonist
- used to treat cardio problems
- lessen risk of bronchospasm; but still contraindicated in asthmatic
- do not usually prolong hypoglycemia
(b1>>b2)
Metropolol
B1-Selective B-adrenergic Antagonist: but also blocks B2 at higher doses
- lessened risk of bronchospasm as opposed to B2 antagonists: still contraindicated in asthmatic patients
- does not usually prolong hypoglycemia: OK to use with diabetics
Phentolamine
- Nonselective a-Adrenergic Antagonist
- a1 = a2: alpha receptor blocker
Prazosin (Minipress): what is it used to treat?
a-1 selective a-Adrenergic Antagonist
- a1>>>>>a2
- used to treat hypertension, benign prostatic hypertrophy
Carvedilol
- mixed antagonist: nonselectively blocks B and a receptors : b1 = b2 ≥ a1 >a2
- very dramatic results in CHF clinical trials
What are three muscarinic cholinergic Agonists?
Acetylcholine (Muscarinic and Nicotinic Agonist)
Bethanechol (M1-5 >>>>NM,NN)
Methacholine
- decrease HR velocity and contraction strength,
- result in bronchial smooth muscle contraction
- increased tone and contraction of extravascular smooth muscles
What are 3 muscarinic Receptor Antagonists? what are their pharmacological uses?
Atropine (Oral, Parenteral, Ophthalmic)
- (M1 = M2 = M3 >>>>>NM,NN)
- blocks ALL muscarinic receptors
- blocks PS slowing of the heart and promotes tachycardia
Ipratropium
- inhalation drug to reverse bronchial constriction and secretion
- used to treat emphysema, chornic bronchitis and sometimes asthma
- often combined with albuteterol to make combivent
Tiotropium (Inhalation only)
- similar effects to ipratropium, but longer lasting
Muscarinic Receptors: where are the 5 different types found? what is the major muscarinic blocker?
M 1 (nerves) (IP3; DAG)
M 2 (cardiovascular) (K+; cAMP)
M 3 (glandular) (IP3; DAG)
M4 & M5 (CNS)
all blocked by atropine
What are two different nicotinic receptors?
Nicotinic:
NM (skeletal muscle) (Na+, K+) blocked by curare
NN (nerves) (Na+, K+) blocked by hexamethonium
Alpha 1 adrenergic effects
- **primary sympathetic influence on arteriolar smooth muscle **
** Epi >= NE >> Iso**
Alpha 1 Agonists: Phenylephrine
- results in vasocostriction - contraction of vascular smooth muscle - no matter where it is.
- Other Effects:
- a1mydriasis (dilates pupil) - contraction of iris radial muscle
- a1 contraction of spleen
- a1 contraction of uterus
- a1 contraction of pilomotor muscle (erects hair)
- a1 increases force of contraction in heart - less important than b1 effect
- stimulation of glycogenolysis
Alpha 2 Adrenergic Receptor
Smooth Muscle contraction
- vasoconstriction – only in certain vascular beds and of minor physiological significance
Epi>= NE >> Iso
B1 Receptors
Think: HEART!!!!
- increase heart rate: chronotropic effect
- increase force contraction: ionotropic effect
Iso > Epi = NE (Dobutamine)
B2 Adrenergic Effects: what are 4 things it is activating
Think- smooth muscle relaxation!!!
- relaxation of bronchioles B2 (drugs that activate B2 receptors are put in inhalers)
- relaxation of vascular smooth muscle B2 (vasodilation, certain vascular beds only)
- relaxation of skeletal muscle : (stimulates potassium uptake)
- metabolic and hormonal (glycogenolysis B2, lipolysis B3, stimulation of insulin and renin release)
Iso > Epi >>> NE (Albuterol)
B2 selective agonists have greater selectivity for lung > heart.
What are effects of Dopamine on Kidneys?
- Renal Affarent Blood Vessels: results in D1 dilation and increased blood flow to the kidneys
- during cardiogenic shock: at low rates dopamine blood flow is improved to kidneys, at high drip rate, kicks up B1 activators. Dopamine is titrated just right to get improved blood flow to kidney and imroved cardiac output, without going too far to get vasoconstriction
What drug would block the decrease in heart rate seen with slow NE prescription? * test question *
Atropine: blocks the reflex of bradycardia
Dobutamine
Pharmacological effects of Propranolol: absolute contraindications *test question*
- don’t use Beta blockers in asthma patients.
B2 stimulatoin helps people
- don’t use Beta blockers with people with diabetes
* would prefer Beta1 blockers for such patients*
What is the effect of ACh on Cardiovascular system?
“Vagal Stimulation” : enhance K+ permeability, decrease in slow Ca2+ current
SA node: decrease chronotropy of heart, and decreased diastolic depolarization
AV node: decreased conduction velocity, increased refractory period
Atrial muscle: decreased contractile strength (negative intropy), decreased refractory period
- can results in atrial flutter or fibrillation
Vessels: little or no PSNS innervation
What are four most imiportant baroreceptor reflex controls of heart rate and blood pressure???
B1: stimulation of HR and force of contraction
Muscarinic: decrease in HR
Alpha 1: vasoconstriction of vessels
Betal 2: vasodilation of vessels
