2 - Cardiovascular Pharmacology Flashcards
Most potent arterial vasopressin available.
Vasopressin
This class of drugs MIMIC, ENHANCE, or BLOCK the actions of acetylcholine in autonomic ganglia and skeletal muscle at nicotine’s receptors or in parasympathetic postganglionic neurons.
Cholinergic drugs
Two important binding sites of acetylcholine. (2)
Ester
Amine
Cholinergic agonists two types.
- Choline esters
2. Alkaloids
Give the 5 choline esters
Give the 3 choline alkaloids
Choline esters
- Choline
- Ach
- Carbamylcholine
- Methacholine
- Bethanecol
Choline alkaloids
- Pilocarpine
- Muscarine
- Arecoline
This drug is almost used exclusively as a provocative agent for identyfying the presence of reactive airway disease. This drug causes bronchoconstricton, increases airway secretions, and reduces peak expiratory flow rate.
Methacholine
Is a choline ester that is relatively selective for the M3 receptors in the urinary and GIT. Used for the treatment of non-obstructing urinary retention.
Bethanecol
Is a choline ESTER used topically to produce miosis in wide angle glaucoma.
Carbamylcholine
Is an alkaloid cholinergic agonist used as a topical miotic agent to reduce IOP. This drug is also used orally to increase salivary and lacrimal gland production in patients with xerostomia.
Pilocarpine
These drugs are used to treat myasthenia gravis, glaucoma and less commonly urinary or intestinal atony. They inhibit the enzyme acetylcholinesterase.
Cholinsterase inhibitors
2 classes of cholinesterase inhibitors (2)
- Carbamoyl esters
2. Quarternary ammonium alcohols
Examples of carbamoyl esters (cholinesterase antagonists) (3)
- Neostigmine
- Pyridostigmine
- Physostigmine
Example of quartenary ammonium compound (cholinesterase inhibitor)
Edrophonium
Cholinesterase inhibitor, a tertiary amine that readily crosses the BBB and inhibits the acetylcholinesterase in the central nervous system.
Physostigmine
Is the ONLY clinically used organophosphate cholinesterase inhibitor, which is applied TOPICALLY for the treatment of glaucoma.
Ecothiophate
What are the 3 common muscarinic antagonists?
- Atropine (belladonna alkaloids)
- Scopolamine (belladonna alkaloids)
- Glycopyrrolate
Muscarinic antagonists that penetrate the BBB (2)
- Atropine
2. Scopolamine
Muscarinic antagonist particularly useful as an IM premedication before midazolam.
Scopolamine
What dose of atropine that is devoid of central nervous system effect?
<2 mg
Dose of atropine that can decrease HR through blockade of M1 receptors
Less than 0.1 mg
What comprises the signs and symptoms of atropine toxicity (5)
Dry as a bone Red as a beet Blind as a bat Hot as a hare Mad as a hatter
Treatment of choice for anticholinergic syndrome
Physostigmine 1 or 2 mg
Atropine toxicity
0.5 - 1.0 mg: Inc HR, xerostomia (dry mouth), thirst, lack of sweat, mild pupillary dilation
2-5 mg: tachycardia, palpitations, mydriasis, cycloplegia, inability to urinate or defecate
10 or greater: fever, hallucinations, coma, death
Most common adrenoreceptor in the skeletal muscles?
B2
Methylation of norepinephrine by what enzyme converts the NE to epinpehrine in the adrenal medullary chromaffin cells.
Phenylehtanolamine N-methyltransferase
Catecholamines and their receptors
Epinephrine: activates a1, b1, b2
: causes vasoconstriction EXCEPT in the blood vessels supplying the SKELETAL MUSCLES
: dose dependent (0.02 ug/kg/minj stimulates B2
: higher doses (>0.1 ug/kg/min) activates a1
Norepinephrine: a1,a2, b1
Dopamine: a1, b1, DA1, DA2
Dobutamine: b1,b2,a1
: potent stimulato of b receptors with little a receptor at inf rates less than 5 ug/kg/min
: dobutamine (-) isomer stimulates a1 rceptor above t ug/kg/min
Isoproterenol: selective B agonist derived from dopamine
: reduces coronary perfusion and decease diastolic filling time
Drug of choice for AHA advanced cardiac life support for malignant ventricular arrhythmias, pulseless electrical activity and asystole.
Epinephrine 1 mg
Why is intramuscular route more preferred over inhalation in pediatric patients with severe croup?
Because rebound edema may occur as a result of relatively short half life.
Most often used for the treatment of refractory hypotension resulting from prnounced vasodilation.
Norepinephrine
Norepinephrine in combination with nitirc oxide scavenge this drug, useful for vasoplegic syndrome.
Methylene blue
What is the drug used to partially counteract the actions of NE on renal blood flow and may preserve renal perfusion and renal output but most likely prevent AKI.
Fenoldopam
Where should NE ideally be administered?
Central venous catheter to avoid tissue necrosis from extravasation.
Is a biochemical precursor of NE. Lower doses < 3 ug/kg/min to dilate renal, mesenteric and splenic arterial blood flow.
Moderate doses (3-8 ug/kg/min) activate which receptors?(2)
High doses (10 ug/kg/min) activate which receptor?
Dopamine
a1 and b1
a1
A b2 receptor agonist that is administered subcutaneously and intramuscularly.
Terbutaline
Is an intravenous selective DA1 receptor agonist that does not exert activity at a or b receptors
Fenoldoopam
This drug exerts both direct and indirect effects. Endocytosis of this drug into a1 and b1 presynaptic postganglionic nerve terminal displaces NE from the synaptic vesicles. The displaced NE is is the released to activate the corresponding postsynaptic receptors to cause vasoconstriction and increased contractility. May cross the placenta and cause fetal acidosis.
Ephedrine
Why is there tachyphylaxis with ephedrine?
Because presynaptic norepinephrine stores are quickly depleted.
a1 adrenoreceptor antagonist drugs
- Prazosin