Transcript 101408 Cardiac Pharm 1130KB Jan 14

Drugs that affect the
Cardiovascular system
Chemeketa Community College
F ’08
P. Andrews, Instructor
LEAD Drugs
• Lidocaine
– Interferes with sodium channels to block conduction abnormalities
• Epinephrine
– Increases heart rate, blood pressure and stimulates liver
• Atropine
– Blocks acetylcholine, speeds heart
• Dopamine
Increases contractile force
• Amiodarone
– Prolongs action potential and refractory period
Let’s Review First
• Most drugs treat dysrhythmias
• Most prevalent
– Tachycardia
– Bradycardia
• Generated through abnormal
impulse formation
(automaticity)
• OR abnormal conductivity
• Dysrhythmias - Most often caused by
imbalance between sympathetic and
parasympathetic nervous systems
Bradycardia
• Excessive parasympathetic
stimulation through muscarinic
receptors
Tachycardia
• Variety of causes
• Ischemia, mycoardial infarction, excessive
sympathetic stimulation
• Develop phase 4
depolarization,
generate abnormal
impulse
– Ectopic foci
• Abnormal
conduction;
– One-way valve
Antidysrhythmics
• SODIUM CHANNEL
BLOCKERS
What do they do, anyway?
• -amide, ester forms of local anesthetics
elevate the threshold of electric excitation
of the nerve
– Enter open, inactive sodium channels
– Anesthetic closes the channel, blocking sodium
influx
• Delays impulse
• Decreases action potential
• Blocks conduction
Lidocaine
• Class
– Antidysrhythmic
• Indications
– VT, Vf, malignant PVC’s
• Action
– Decreases ventricular automaticity & excitability
– Raises fibrillation threshold
– Decreases conduction in ischemic cardiac tissue
without affecting normal conduction
• Contraindications
– Advanced AV block (Mobitz II , 3rd degree
blocks
– Torsades de pointes
– Stokes-Adams syndrome
• Precaution:
– Heart rate less than 60
– Hepatic disease - reduce by 50%
– >70 y/o – reduce by 50%
• Side effects
–
–
–
–
–
–
–
–
Drowsiness
Dizziness
Confusion
Hypotension
Nausea, vomiting
Dysrhythmias
Respiratory depression
Cardiac arrest
• Route & Dosage:
– Loading dose of 1 – 1.5 mg/kg
IVP q 5 min. Max dose of 3 mg/kg
– After perfusion is reestablished,
admin. Lidocaine gtt at 2-4
mg/min (start gtt at 1 mg/min if pt
> 70 y/o
• How supplied
– 10 mg/ml in 100 mg preload
Lidocaine is drug of choice for
• Most types of drug-induced monomorphic
VT or Vf, and for VT, Vf associated with
cocaine-induced myocardial ischemia
Antidysrhythmics
• Potassium Channel Blockers
amiodarone (Amrinone,
Cordarone)
• Class
– antiarrhythmic
• Indications
– recurrent VF, unstable VT
– When other therapies are ineffective
• Action
– Prolongs action potential and refractory period
– Slows sinus rate, increases PR, QT intervals
• Contraindications
– Severe sinus node dysfunction
– 2nd and 3rd degree AV block
• Precautions
– CHF, severe pulmonary or liver disease
• Adverse reactions
– ARDS, pulmonary fibrosis, CHF, worsening
of arrhythmias
– Liver function abnormalities
– Anorexia, constipation, N/V, ataxia,
involuntary movement, paresthesia,
periphreal neuropathy, tremors
– Bradycardia, hypotension
– Dizziness, fatigue, malaise, corneal
microdeposits
• Route & dosage
– Requires large initial loading dose
(IV route) to prevent delay in onset action
– Must use filter needle
– Draw up slowly – Foams!
• For VT hemodynamically stable (SBP> 85)
– 150 mg IV over 10-30 minutes
– 900 mg IV over 24 hrs by infusion
– Repeat 150 mg IV bolus for VT
• For VT/VF unstable or no BP
– 150-300 mg IV bolus
– IV infusion (1mg/min)
– May repeat bolus
• Not water soluble – must use solvent
Polysorbate 80
• Polysorbate 80 clinical effects:
– Decrease heart rate
– Depress AV node conduction
– Increase atria and ventricular
refractory periods
– Available only in glass ampules
• How supplied
– 50mg/ml in 3-ml ampules
Bretylium Tosylate (Bretylol)
• Class; antiadysrhythmic
– Different from all other antidysrhythmics
– Does not suppress automaticity
– Has no effect on conduction velocity
• Indications
– VT, Vf refractory to lidocaine and defibrillation
– Recurrent Vf
– VT with a pulse that fails to respond to
lidocaine or procainamide
– Wide complex tachycardias not controlled by
lidocaine and adenosine
• Action
– Causes an initial but transient release of
norepinephrine; effect lasts ~ 20 min.
– Then inhibits release of norepinephrine and
blocks reuptake of norepinehprine, resulting in
depletion of norepinephrine. Results in:
• Increased fibrillation threshold
• Prolonged effective refractory period
• Suppression of reentry dysrhythmias
• Contraindication and precautions
– No contraindications when used for Tx of lifethreatening dysrhythmias
– Contraindicated in Torsades
– Can result in prolonged hypotension in
postresuscitation phase
• Side effects
–
–
–
–
–
Initial transient elevated BP followed by hypotension
Dizziness, syncope
Angina
Bradycardia
If administered by rapid IVP, N/V
• Dosage
– Vf, pulseless VT: 5 mg/kg IVP
• Repeat with 10 mg/kg q 15 min to max dose of 3035 mg/kg
– If conversion, administer bretylium drip at 1-2
mg/min.
• How supplied
– 50 mg/ml in 10 ml preload
Antidysrhythmics
• Calcium Channel Blockers
Verapamil (Isoptin, Calan)
• Class
– Antianginal, Antiarrhythmic, antihypertensive agent
• Indications
– Hypertension, angina, Prinzmetal’s angina, Af or AF
with rapid ventricular response
• Action
– Inhibits transport of calcium into myocardial and
vascular smooth muscle
– Decreases SA and AV conduction
• Contraindications
– Hypersensitivity
• Precautions
– Severe hepatic impairment
• Adverse reactions, SE
– Arrhythmias, CHF
• Dosage and route
– 5 – 10 mg, IV
• How supplied
– 2.5 mg/ml in 2 & 4 ml vials, ampules and
syringes
diltiazem (Cardizem)
• Class
– Antianginal, antiarrhythmic, antihypertensive
• Indication
– Hypertension, angina, SVTs and Af & AF with rapid
ventricular response
– NEW ONSET Af/AF (onset 48 hours or less)
• Diltiazem OR cardioversion
• Action
– Inhibits the transport of calcium into myocardial and
vascular smooth muscle
• Contraindications
– Hypersensitivity
– Sick sinus syndrome
– 2nd or 3rd degree AV block
• Precautions
– Severe hepatic impairment
• Adverse reactions, SE
– Arrhythmias
– CHF
– Peripheral edema
• Dosage & route
– 0.25 mg/kg
– May repeat in 15 minutes with dose of 0.35 mg/kg
– Follow with gtt at 10 mg/hr
• How supplied
– 5 mg/ml in 10 ml vials
– 25 mg preloads
Antidysrhythmics
• Miscellaneous
Adenosine (Adenocard)
• Class
– Antiarrhythmic agent
• Indication
– Conversion of PSVT
– As a diagnostic tool to assess myocardial
perfusion
• Action
– Restores normal sinus rhythm by interrupting
re-entry pathways in AV node
– Slows conduction through AV node
• Contraindications
– 2nd or 3rd degree block
• Precautions
– Asthma
– Unstable angina
• Adverse reactions & side effects
– SOB
– Facial flushing
– Transient arrhythmias
• Dosage & route
– 6 mg rapid IVP
– Repeat in 1 – 2 min. prn at 12 mg rapid IVP
– Repeat in 1 – 2 min. prn at 12 mg rapid IVP
• How supplied
– 6 mg and 12 mg preload syringes or vials
• Onset is immediate
• Duration is 1 – 2 min
• Note: Proximal IV, RAPID bolus, 20 ml
flush with arm raised is critical!!
digoxin (Lanoxin)
• Class
– Antiarrhythmic agent
– Cardiotonic and inotropic agent
• Indications
–
–
–
–
CHF
Tachyarrhythmias
Af & AF
PAT
• Action
– Increases force of myocardial contractility
– Prolongs refractory period of AV node
– Decreases conductiion through SA and AV
nodes
• Contraindications
–
–
–
–
Hypersensitivity
Uncontrolled ventricular arrhythmias
AV block
IHSS
• Precautions
– Electrolyte abnormalities
• Adverse reactions, SE
–
–
–
–
Dysrhythmias
Fatigue
Blurred, yellow vision
Anorexia, N/V
• Dosage & route
– 0.6 – 1.0 mg (10-15 mcg/kg) initially
– Give additional fractions at 4 – 8 h intervals
– Total dose 200 mg
• How supplied
– 0.25 mg/ml in 1 ml preload
Magnesium Sulfate
• Class: CNS depressant, anticonvulsant.
• Indications
–
–
–
–
Refractory Vf/pulseless VT
Torsades de Pointes
Digoxin-induced VT/Vf
Seizures 2ndary to eclampsia
• Contraindications and precautions
–
–
–
–
None in refractory Vf, VT, Torsades
Renal disease
Heart block
Hypermagnesemia
• Side effects
–
–
–
–
–
–
Hypotension
Asystole
Cardiac arrest
Respiratory and CNS depression
Flushing
Sweating
• Dosage & Route
–
–
–
–
Refractory VT: 1-2 gm IVP over 1-2 min.
Refractory Vf: 1-2 gm IVP over 1-2 min.
Digoxin-induced VT/Vf: 2 gm IVP
Seizures 2ndary to eclampsia: 1-4 gm slow IVP
Anticholingergics
Atropine Sulfate
• Class
– Anticholinergic (parasympatholytic)
– Muscarinic antagonist
• Indications
–
–
–
–
Symptomatic bradycardia
Asystole
PEA if bradycardia
Insecticide poisoning
• Action
– Blocks the effects of acetylcholine at
muscarinic receptors which would cause a
decrease in heart rate.
• Contraindications and precautions
– Glaucoma or myasthenia gravis
– Can cause tachycardia
– Administer cautiously in pt. With MI or
myocardial ischemia
• Side effects
–
–
–
–
–
Dry mouth
Blurred vision
Urinary retention
Constipation
Tachycardia; possibly VT, Vf
• Dosage & Route
– Symptomatic bradycardia; 0.5 mg IVP q 5 min.
Max dose 0.04 mg/kg
– Asystole; 1.0 mg IVP q 5 min. Max dose 0.04
mg/kg
– PEA; 1.0 mg IVP q 5 min. Max dose 0.04
mg/kg
– Pesticide poisoning; 2-5 mg IV q 15-30 min.
Antihypertensives
• Diuretics
Furosemide (Lasix)
• Class
– Loop diuretic agent
– Antihypertensive agent
• Indication
– Edema 2ndary to CHF
– hypertension
• Action
– Inhibits reabsorption of sodium and chloride
from the loop of Henle and distal renal tubule
• Contraindictions
– Hypersensitivity; cross-sensitivity with
thiazides and sulfonamides may occur
• Precautions
– Severe liver disease with cirrhosis or ascites
• Adverse reactions, SE
– Dehydration, hypochloremia, hypokalemia,
hypomagnesemia, hyponatremia, hypovolemia,
metabolic acidosis
• Dosage & route
– 20 – 80 mg/day (prehospital setting: generally
double the patient’s home dose up to 80 mg
IVP)
• How supplied
– 10 mg/ml in 4 or 8 ml preloads
Other Vasodilators and
Antianginals
Nitroglycerin
• Class: Antianginal agent; Nitrate
• Indications:
– Relief of acute anginal pain
– Hypertension
– CHF with APE
• Action:
– Relaxes vascular smooth muscle; decreases
myocardial workload and oxygen demand
• Contraindications
–
–
–
–
–
Hypotension
Hypovolemia
Intracranial bleed
Aortic stenosis
Recent Viagra use
• Side effects
–
–
–
–
–
H/A 2ndary to vasodilation
Hypotension
N/V
Tachycardia
Flushing
• Dosage & Route
– Tablets
• 0.3 - 0.4 mg SL q 3-5 min.
• Max 3 doses
– Paste
• 1 – 2 cm (6-12 mg) topically
– Spray
• 1 - 2 sprays (0.4 - 0.8 mg) SL
– IV
• Mix 25 mg in 250 ml D5W (100
mcg/ml); infuse at 5 mcg/min, titrated
to effect
Hemostatic Agents
Antiplatelets
Aspirin (Salicylate)
• Class
– Antiplatelet agent
• Indication
–
–
–
–
Inflammatory disorders
Fever
TIA
MI
• Action
– Produces analgesia
– Reduces inflammation and fever by inhibiting
the production of prostoglandins
– Decreases platelet aggregation
• Contraindications
– Hypersensitivity
– Bleeding disorders or thrombocytopenia
• Precautions
–
–
–
–
–
GI bleeds or ulcers
Chronic alcohol use/abuse
Severe renal disease
Viral infections
Pregnancy
• Adverse reactions, SE
–
–
–
–
–
GI bleeding
Anaphylaxis
Laryngeal edema
Dyspepsia, epigastric distress
Heartburn, nausea
• Dosage & route
• Pain, Fever
– PO, Rectal
• 325 – 500 mg q 3 h OR
• 325 – 650 mg q 4 h
• Not to exceed 4 g/day
• Cardiac chest pain
– PO
– 81 mg x 3 chewable childrens aspirin (243 mg)
• (UNLESS TAKING COUMADIN)
• How supplied
• Childrens aspirin, 81 mg tablets
• Aspirin 325 - 500 mg tablets
• Thrombolytics
Alteplase (Activase, t-PA)
• Class
– Thrombolytic agents (plasminogen activators)
• Indications
– Coronary thrombosis
– Acute ischemic stroke
• Action
– Converts plasminogen to plasmin, which is then
able to degrade fibrin in clots.
• Contraindications
–
–
–
–
–
Active internal bleeding
Hx of CVA
Recent CNS trauma or surgery
Severe uncontrolled hypertension
Known bleeding tendencies
• Precautions
– Recent (10 days) major surgery
– GI or GU bleeding
• Adverse reactions, SE
–
–
–
–
–
Intracranial hemorrhage
GI bleeding, retroperitoneal bleeding
GU tract bleeding
Anaphylaxis
Reperfusion arrhythmias
• Dosage & route
– MI
• 60 mg over first hour, 20 mg over 2nd
hour, 20 mg over 3rd hour for total
dose of 100 mg.
• How supplied
powder for injection, packaged with
sterile water for injection
20 mg vial or 50 mg vial
Reconstitute with 20 mg or 50 mg using
18-ga needle
Avoid excess agitation; solution may
foam
• Start two IV lines first
Other Cardiac Medications
Calcium Chloride & Calcium
Gluconate
• Class
– Mineral, electrolyte
• Indications
– Hyperkalemia
– Hypermagnesemia
– Cardiac arrest
• Action
– Acts as an activator in transmission of nerve
impulses and contraction of cardiac, skeletal,
smooth muscles
• Contraindications
– Hypercalcemia
– Vf
• Adverse reactions,SE
–
–
–
–
Cardiac arrest
Arrhythmias
Constipation, nausea
Phlebitis
• Route & dosage: cardiac arrest
– 7 – 14 mEq IVP
• How supplied
• Calcium chloride 10%
– 1.36 mEq/ml in 20 ml preloads
• Calcium gluconate 10%
– 0.45 mEq/ml in 20 ml preloads
Dopamine (intropin)
• Class
– Cardiotonic and inotropic agent
– Vasopressor
• Indications
– Improve BP
– Improve cardiac output
• Action
– Small doses stimulate dopaminergic receptors,
producing renal vasodilation
– Large doses stimulate dopaminergic and betaadrenergic receptors, producing cardiac
stimulation and renal vasodilation
– Larger doses stimulate alpha-adrenergic
receptors and may cause renal vasoconstriction
Sodium Bicarbonate
• Class: Alkalinizing agent
• Indications:
– Metabolic acidosis 2ndary to cardiac arrest
– Cyclic antidepressants
• Action:
– Neutralizes excess acid
• Contraindications
– Tachyarrhythmias
– Pheochromoctoma
– Hypersensitivity to bisulfites
• Precautions
– Hypovolemia
– MI
• Adverse reactions, SE
– Arrhythmias, hypotension
• Route & dosage
– Renal vasodilation – 0.5 – 3 mcg/kg/min IV
– Cardiac stimulation – 2.0 – 10.0 mcg/kg/min IV
– Increased peripheral vascular resistance – 10
mcg/kg/min; titrate to effect
• How supplied
– 40 mg/ml or 80 mg/ml in preload or vial
– Premixed injection: 1600 mcg/ml in 250 and
500 ml D5W
Epinephrine 1:10,000
• Class
– Direct-acting catecholamine secreted by the
adrenal medulla in response to sympathetic
stimulation.
• Indications
–
–
–
–
–
Asystole
Vf
Pulseless VT
PEA
Acute bronchospasm associated with asthma or
COPD
– Anaphylaxis
• Action
– Stimulates beta1, beta2 and alpha1 receptors.
– Effect on beta receptors significantly more profound
than on alpha receptors.
– Beta1 stimulation results in increased contractility,
increased heart rate, increased AV conduction
– Can cause spontaneous myocardial contraction in
asystole.
– Increases likelihood of successful defibrillation
– Beta2 stimulation results in bronchodilation,
vasodilation in skeletal muscle
– Stimulation of alpha1 receptors causes vasoconstriction
• Note: Vascular effects are dose-related.
– At low doses, beta2 receptors predominate with
decreased total peripheral resistance and
decreased BP
– With larger doses, alpha effects predominate
with increased peripheral vascular resistance
and increased BP.
• Contraindications and precautions
– No contraindications in cardiac arrest
– Protect Epi from light
– Unstable in alkaline solutions I.e., Sodium Bicarbonate
• Side effects
–
–
–
–
CNS stimulation
H/A, dizziness, pallor
N/V
Palpitations
• Dosage
– Cardiac Arrest: 1 mg IVP q 3-5 min.
– Endotracheal admin. 2 – 2.5 x IV dose
– Acute bronchospasm assoc. with asthma,
COPD: 0.3 mg – 0.5 mg 1:1,000 solution SC q
5-20 min.
• How supplied
– 1 mg/ml in 10 ml preload
Propranolol (Inderal)
• Class
– Antianginal agent
– Arrhythmic agent
– Antihypertensive agent
• Indication
–
–
–
–
VT, Vf, Af, AF, PSVT
Hypertension
Angina
Anterior MI w/ HTN, tachycardia
• Action
– Blocks stimulation of beta1 and beta2 adrenergic
receptor sites
• Contraindication
–
–
–
–
Uncompensated CHF
Pulmonary edema
Cardiogenic shock
Bradycardia or heart block
• Adverse reaction, SE
– Arrhythmias, bradycardia, CHF, pulmonary edema
– Fatigue, weakness
• Dosage & route
– 1 – 3 mg; repeat after 2 min and again in 4 hours prn
• How supplied
– 1 mg/ml in 3 ml preload
• Contraindications and precautions
– None in confirmed metabolic acidosis
– Precaution: Tissue necrosis if infiltrates
• Side effects:
– Metabolic alkalosis
– Decreased potassium
– Fluid overload
• Dosage:
– 1 mEq/kg IVP followed by 0.5 mEq/kg q 10
min.
• How supplied
– 1 mEq/ml in 50 ml preload
Vasopressin
• Class
– Antidiuretic hormone
– Non-adrenergic peripheral vasoconstrictor
• Indications
– Alternative to Epinephrine in refractory Vf
– May be effective with asystole, PEA
• Action
– Directly stimulates smooth muscle receptors
– Increases coronary perfusion pressure
• Contraindications, precautions
– None in cardiac arrest
• Adverse reactions, SE
– unknown
• Dosage & route
– 40 units, IVP, one time only
• How supplied
– unknown
Off you go….
• A 78 y/o female, found unconscious and
unresponsive by her daughter. Down time
unknown. Unsure if the pt. Is breathing or
has a pulse.
• PMH: HTN, AMI (2003), CVA (1998) with
left-sided deficits
• You arrive to find the pt. Supine on the
living room floor, unconscious,
unresponsive. Weak carotid pulse is present.
• B/P 82/40, RR 8
• ECG; Mobitz II with frequent multifocal
PVCs
•
•
•
•
DDX?
TX?
Why?
Anything else?