Mechanism Of Action Flashcards
Aspirin, Acetylsalicyclic Acid, ASA
Brand: Bufferin, Anacin, APC
Mechanism of Action?
- In small doses aspirin blocks thromboxane A2, a potent platelet aggragant and vasoconstrictor.
- This property has lead to its use in the acute phase of management of myocardial infarction.
- Decreased platelet aggregation.
Methylprednisolone Sodium Succinate
Brand: Solu-Medrol
Mechanism of Action?
- Enters target cells and causes many complex reactions that are responsible for its anti-inflammatory and immunosuppressive effects; thought to stabilize cellular and intracellular membranes.
Activated Charcoal
Brand: Charcola, Actidose-Aqua
Mechanism of Action?
- Pharmacological: Physical binding (adsorption) of toxins from GI tract.
- Clinical Effects: Prevents/reduces systemic absorption of toxins.
Albuterol Sulfate
Brand: Proventil, Ventolin
Mechanism of Action?
- B agonist (primarily B2); relaxes bronchial smooth muscle, resulting in bronchodilation; also relaxes vascular and uterine smooth muscle; decreases airway resistance.
Atropine Sulfate
Brand: Atropine
Mechanism of Action?
Pharmacological: Competitive antagonist of acetylcholine at muscarinic receptor sites (smooth muscle and glands, blocking parasympathetic response and allowing sympathetic response to take over).
Clinical:
- CV: Increased heart rate (positive chronotropic effect); increased conduction velocity; increased force of contraction (slight).
- Resp: Decreased mucous production; increased bronchial smooth muscle relaxation (bronchodilation).
- GI: Decreased GI secretionand motility.
- GU: Decreased urinary bladder tone.
- Misc: Mydriasis (pupillary dilation); decreased sweat production.
Ipratropium Bromide
Brand: Atrovent
Mechanism of Action?
Anticholinergic (parasympathetic) agent appears to inhibit vagally-mediated reflexes by antagonizing the action of acetylcholine, the transmitter released from the vagal nerve.
Diphenhydramine HCl
Brand: Benadryl
Mechanism of Action?
- Blocks cellular histamine receptors, but does not prevent histamine release; results in decreased capillary permeability and decreased vasodilation, as well as prevention of bronchospasm.
- Has some anticholinergic effects.
Dextrose 50%
Brand: Dextrose 50%, D50
Mechanism of Action?
- Pharmacological: Aerobic metabolic substrate (ATP production).
- Clinical Effects: Reverse CNS effects of hypoglycemia by rapidly increasing serum glucose levels.
- Provides short-term osmotic diuresis.
Diazepam
Brand: Valium
Mechanism of Action?
Acts on parts of the limbic system, the thalamus, and hypothalamus producing calming effects; decreases seizures by increasing the seizure threshold; transient analgesia; amnesic; sedative.
Diltiazem
Brand: Cardizem
Mechanism of Action?
- Pharmacological: Inhibits calcium ion influx across cell membranes during cardiac depolarization, decreases SA and AV conduction and dilates coronary and peripheral arteries and arterioles.
- Clinical: Slows the rapid ventricular rate associated with arterial fibrillation and atrial flutter, and reduces coronary and peripheral vascular resistance.
Dopamine
Brand: Intropin
Mechanism of Action?
- Immediate metabolic precursor to norepinephrine.
- Effects are dose-dependent:
- 1-2 ug/kg/min Acts on dopaminergic receptors to stimulate cerebral, renal and mesenteric vasculature to dilate; HR and BP are usually unchanged; may increase urine output.
- 2-10 ug/kg/min B1stimulant action is primary effect (increases cardiac output and partially antagonizes the a-adrenergic-mediated vasoconstriction. Overall effect is increased cardiac output and only modest increase in systemic vascular resistance (SVR).
- 10-20 ug/kg/min a-adrenergic effects predominate resulting in renal, mesenteric and peripheral arterial and venous vasoconstriction with marked increase in SVR, pulmonary vascular resistance and further increased preload.
- 20 ug/kg/min Produces hemodynamic effects similar to norepinephrine; may increase HR and O2 demand to undesirable limits.
Epinephrine
Mechanism of Action?
- Pharmacological: Direct acting a and B agonist; a-bronchial, cutaneous, renal, and visceral arterial constriction (increased systemic vascular resistance); B1-positive inotropic and chronotropic actions (increases myocardial workload and oxygen requirements), increases automaticity and irritability; B2 bronchial smooth muscle relaxation and dilation of skeletal vasculature. Other- blocks histamine release.
- Clinical: Cardiac Arrest- increases cerebral and myocardial perfusion pressure; increases systolic and diastolic blood pressure; increases electrical activity in the myocardium; can stimulate spontaneous contraction in asystole. Bradycardia- increases heart rate, increases BP. Bronchospasm/Anaphylaxis- reverse signs/symptoms.
Etomidate
Mechanism of Action?
- Produces hypnosis rapidly causing CNS depression and anesthesia.
- No analgesic effect.
Furosemide
Brand: Lasix
Mechanism of Action?
- Pharmacologic: Inhibits electrolyte reabsorption in the ascending Loop of Henle. Promotes excretion of sodium, potassium, chloride. Vasodilation increases venous capacitance and decreases afterload.
- Clinical: Diuresis
Glucagon
Mechanism of Action?
- Pharmacologic: Acts only on liver glycogen, converting it to glucose. Counteracts the effect of insulin. Relaxes GI smooth muscle causing dilation and decreased motility. Cardiac inotrope.
- Clinical: May reverse hypoglycemia (if patient has glycogen stored in liver) within 4-8 minutes (could be as long as 15 or more).
Lidocaine
Brand: Xylocaine
Mechanism of Action?
- Decreases automaticity by slowing the rate of spontaneous phase 4 depolarization.
- Terminates re-entry by decreasing conduction in re-entrant pathways (by slowing conduction in ischemic tissue, equalizes conduction speed among fibers).
- Increases ventricular fibrillation threshold.
Magnesium Sulfate
Mechanism of Action?
- Pharmacology: Second most plentiful intracellular cation; essential intracellular potassium replenishment and activity of many enzymes; important role in neurochemical transmission and muscular excitability (may decrease acetylcholine released by nerve impulses); decreases myocardial irritability and neuromuscular irritability.
- Clinical: Cardiac-reduces ventricular irritability, especially when associated with hypomagnesemia; inhibition of muscular excitability.
Midazolam Hydrochloride
Brand: Versed
Mechanism of Action?
- CNS effects are mediated through the inhibitory neurotransmitter gamma-aminobutyric acid (GABA).
- Acts at the limbic, thalamic and hypothalamic levels of the CNS, producing anxiolytic, sedative, hypnotic, and anticonvulsant effects.
- Capable of producing all levels of CNS depression, from mild sedation to coma.
Morphine Sulfate
Mechanism of Action?
- Alleviates pain by acting on the pain receptors in the brain; elevates pain threshold.
- Depresses CNS; depresses brainstem respiratory centers; decreases responsiveness to changes in PaCO2.
- Increases venous capacitance (venous pooling), vasodilates arterioles, reducing preload and afterload.
- Histamine release.
Naloxone HCl
Brand: Narcan
Mechanism of Action?
- Competitive inhibition at narcotic receptor sites.
- Reverses respiratory depression secondary to narcotics.
Nitroglycerin
Brand: Nitrostat, Tridil
Mechanism of Action?
- Smooth muscle relaxant acting on vascular, uterine, bronchial, and intestinal smooth muscle.
- Reduces workload on the heart by causing blood pooling (decreased preload).
- Arteriolar vasodilation (decreased afterload).
- Coronary artery vasodilation.
- Increases blood flow to myocardium.
- Decreases myocardial O2 demand.
Sodium Bicarbonate 8.4%
Mechanism of Action?
- Buffers H* and increases pH
Succinylcholine
Mechanism of Action?
- Combines with cholinergic receptors of the motor end plate to produce depolarization.
- Hydrolyzed by acetylcholinesterase
Thiamine HCl
Brand: Betalin
Mechanism of Action?
- Required for carbohydrate metabolism.
- Deficiency leads to anemia, polyneuritis, Wernicke’s encephalopathy, cardiomyopathy.
- Administration may reverse symptoms of deficiency, but effects are dependent upon duration of illness and severity of disease.
Vasopressin
Mechanism of Action?
- Causes vasoconstriction (pressor effect) of peripheral, cerebral, pulmonary, and coronary vessels.
Verapamil
Brand: Isoptin, Calan, Verelan
Mechanism of Action?
- Blocks calcium ion influx into cardiac and smooth muscle cells causing a depressant effect on the contractile mechanism resulting in negative inotropy.
- Reduces contractile tone in vascular smooth muscle resulting in coronary and peripheral vasodilation.
- Slows conduction and prolongs refractory period in the AV node due to calcium channel blocking.
- Slows SA node discharge.
- In summary, decreases myocardial contractile force and slows AV conduction.
Ondansetron
Brand: Zofran
Mechanism of Action?
Selectively blocks serotonin 5-HT3 receptors located in the CNS at the chemoreceptor trigger zone and in the peripheral nervous system on nerve terminals of the vagus nerve.
Adenosine
Brand: Adenocard
Mechanism of Action?
- Slows conduction time through AV node; can interrupt re-entrant pathways through the AV node.
- Slows sinus rate.
- Larger doses decrease BP by decreasing peripheral resistance.
Amiodarone
Brand: Cordarone
Mechanism of Action?
- Multiple effects on sodium, potassium, and calcium channels.
- Prolongs action potential, refractory period, and ventricular automaticity (potassium channel blockade).
- Slows membrane depolarization and impulse conduction (sodium channel blockade).
- Negative chronotropic activity in nodal tissue, rate reduction, and antisympathetic activity (calcium channel and B-blockade).
- Dilates coronary arteries due to calcium channel and alpha-adrenergic blocking action.
Calcium Chloride
Brand: Calcium Chloride
Mechanism of Action?
- Increases extracellular and intracellular calcium levels.
- Stimulates release of catecholamines.
- Increases cardiac contractile state (positive inotropic effect).
- May enhance ventricular automaticity.
- Inhibits the effects of adenosine on mast cells.
Oxytocin
Brand: Pitocin, Syntocin
Mechanism of Action?
Binds to oxytocin receptor sites on surface of uterine smooth muscles; increases force and frequency of uterine contraction.
Phenylephrine Nasal Spray
Brand: Neo-synephrine Nasal Spray
Mechanism of Action?
Stimulates a-receptors in the blood vessels of the mucosa which causes their constriction and thereby decreases the risk of nasal bleeding.
Bumetanide
Brand: Bumex
Mechanis, of Action?
Inhibits electrolyte reabsorption in the ascending loop of Henle leading to diuresis.
Cimetidine
Brand: n/a
Mechanism of Action?
Competitively inhibits action of histamine at the H2 receptor sites of parietal cells, decreasing gastric acid secretion.
Dexamethasone Sodium Phosphate
Brand: Decadron
Mechanism of Action?
Improves lung function and myocardial performance; stabilization of lysosomal and cell membranes, inhibition of compliant-induced granulocyte aggregation, rightward shift in oxygen-hemoglobin dissociation curve, inhibition of prostaglandin and leukotriene production, increase increase in surfactant production, decrease in pulmonary edema, relaxation of bronchospasm.
Fentanyl Citrate
Brand: n/a
Mechanism of Action?
- Alleviates pain by acting on the pain receptors in the brain; elevates pain threshold.
- Depresses CNS; depresses brainstem respiratory centers; decreases responsiveness to changes in PaCO2.
- Increases venous capacitance (venous pooling) and vasodilates arterioles thereby reducing preload and afterload.
Lorazepam
Brand: Ativan
Mechanism of Action?
Agent has high affinity for the gamma-amino butyric acid (GABA) benzodiazepine receptor complex without displacing GABA, (GABA is the major inhibitory neurotransmitter in the brain). It exerts tranquilizing action on the CNS.
Nalmefene
Brand: Revex
Mechanism of Action?
- Competetive inhibition at narcotic receptor sites.
- Reserves respiratory depression secondary to narcotics.
Nitrous Oxide 50%
Brand: Nitronox
Mechanism of Action?
Centrally acting agent that produces CNS depression and elevation of the pain threshold.
Racemic Epinephrine
Brand: n/a
Mechanism of Action?
- Alpha-receptor stimulation: causes vasoconstriction, which results in reduction of mucosal and submucosal edema.
- Beta-receptor stimulation: bronchodilation, reduction in airway smooth muscle spasm.
