Drugs that affect the Cardiovascular system

Drugs that affect the Cardiovascular system

Chemeketa Community CollegeF ’08

P. Andrews, Instructor

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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 solventPolysorbate 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 life-threatening

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 30-35 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 suppliedpowder for injection, packaged with sterile water for injection20 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 beta-

adrenergic 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?