DRUGS AFFECTING CARDIOVASCULAR SYSTEM

CARDIOTONICS

?• Cardiotonic agents are drugs used to

increase the contractility and output in a hypodynamic heart without propotionate increase in 02 consumption

• Commonly used in the treatment of heart failure (HF)

• Cardiotonic (inotropic) drugs affect the intracellular calcium levels in the heart muscle, leading to increased contractility.

• This increase in contraction strength leads to increased cardiac output, which causes increased renal blood flow and increased urine production

TYPES

1. Cardiac glycosides2. Phosphodiesterase inhibitors

CARDIAC GLYCOSIDES• Digoxin (Lanoxin) commonly used drug

• The cardiac glycosides were originally derived from Digitalis purpurea (Common Foxglove)

Foxglove plantDigitalis lanata

Mechanism of action

• Digoxin increases intracellular calcium and allows more calcium to enter myocardial cells during depolarization. That results

1. Increased force of myocardial contraction (a positive inotropic effect)

2. • Increased cardiac output and renal perfusion

3. Slowed heart rate, owing to slowing of the rate of cellular repolarization (a negative chronotropic effect)4.Decreased conduction velocity through the atrioventricular(AV) node

INDICATIONS

• Heart failure (HF)• Atrial flutter• Atrial fibrillation• Paroxysmal atrial tachycardia

Dosage

• Digoxin is available for oral and parenteral administration.

• Oral- 0.75–1.25 mg PO• IV-0.125–0.25 mg IV

• Onset of action - 30–120 minutes when taken orally, 5–30 minutes when given intravenously

Contraindications

• hypersensitivity to digitalis preparations• ventricular tachycardia or fibrillation• heart block or sick sinus syndrome• idiopathic hypertrophic subaortic stenosis

(IHSS)• acute MI• Renal failure

Adverse Effects• headache, weakness, drowsiness and

vision changes• Digitalis toxicity ( serious side effect)

Digitalis toxicity

• A serious syndrome that can occur when digoxin levels are too high

• Normal level- 0.5 -2.0 ng/ml signs and symptoms – anorexia, nausea,

vomiting, malaise, depression, irregular heart rhythms including heart block, atrial arrhythmias, and ventricular tachycardia

• Antidote- Digoxin immune Fab (DigiFab)

Nurses responsibilities

• Assess for contraindications or cautions• Perform a physical assessment• Assess cardiac status closely, including

pulse and blood pressure• Monitor apical pulse for 1 full minute

before administering the drug

• Hold the dose if the pulse is less than 60 beats/min in an adult or less than 90 beats/min in an infant; retake the pulse in 1 hour. If the pulse remains low, document it, withhold the drug, and notify the prescriber

• Monitor the pulse for any change in quality or rhythm

• Administer intravenous doses very slowly over at least 5 minutes to avoid cardiac arrhythmias and adverse effects.

• Avoid administering the oral drug with food or antacids to avoid delays in absorption

• Obtain digoxin level as ordered; monitor the patient for therapeutic digoxin level (0.5–2 ng/mL)

• Maintain emergency equipment on standby if digoxin toxicity develops

• Provide thorough patient teaching, including the name of the drug, dosage prescribed, technique for monitoring pulse and acceptable pulse parameters, dietary measures if appropriate, measures to avoid adverse effects, warning signs of possible toxicity and need to notify health care provider

PHOSPHODIESTERASE INHIBITORS

• milrinone (Primacor)• This drugs block the enzyme

phosphodiesterase.This blocking effect leads to an increase in myocardial cell cyclic adenosine monophosphate (cAMP), which increases calcium levels in the cell

INDICATIONS

• short-term treatment of HF that has not responded to digoxin or diuretics alone or that has had a poor response to digoxin, diuretics, and vasodilators

DOSAGE

• Intravenous• (PRIMACOR IV 10Mg/ml inj) dose- 50 microgram/kg iv bolus followed

by 0.4-1.0 microgram/kg/min infusion

Contraindications• hypersensitivity to phosphodiesterase

inhibitors• severe aortic or pulmonic valvular disease• acute MI

Adverse Effects• ventricular arrhythmias (which can

progress to fatal ventricular fibrillation), hypotension, and chest pain

• GI effects include nausea, vomiting, anorexia, and abdominal pain

• Thrombocytopenia occurs frequently with milrinone

• Precipitates form when these drugs are given in solution with furosemide

Nurses responsibilities

• Assess for contraindications or cautions: any known allergies to these drugs or to avoid hypersensitivity reactions;

• acute aortic or pulmonic valvular disease, • acute myocardial infarction • ventricular arrhythmias

• Pregnancy and lactation• Assess cardiac status closely, including

pulse and blood pressure• Protect the drug from light to prevent drug

degradation• Monitor input and output and record daily

weight

• Monitor platelet counts before and regularly during therapy to ensure that the dose is appropriate, inspect the skin for bruising or petechiae to detect early signs

of thrombocytopenia• Provide life-support equipment on standby

• Provide thorough patient teaching, including the name of the drug, dosage prescribed, measures to avoid adverse effects, warning signs of problems, and the need for periodic monitoring and evaluation

ANTIANGINALS

ANGINA• It is a pain syndrome due to induction of

an adverse oxygen supply/demand situation in a portion of myocardium

• Antianginal drugs are used to help restore the appropriate supply-and-demand ratio in oxygen delivery to the myocardium.

How they act

• These drugs can work to improve blood delivery to the heart muscle

• (1) by dilating blood vessels (i.e.,increasing the supply of oxygen)

(2) by decreasing the work of the heart (i.e.decreasing the demand for oxygen).

Classification

• Nitrates a. short acting nitrates Eg: Glyceryl trinitrate (Nitroglycerine) b.Long acting nitrates Eg; Isosorbide dinitrate (sorbitrate)• betA-BLOCKERS Eg; Atenelol, Propanalol

• Calcium channel blockers a. phenyl alkamine Eg: verapamil b. benzothiazepine Eg: Diltiazem c. Dihydropyridines Eg: Nifidipine, Amlodipine

• Potassium channel openers Eg: Nicorandil• OTHers Eg: Ivabradine

Nitrates• Nitrates are drugs that act directly on

smooth muscle to cause relaxation and to depress muscle tone

• isosorbide dinitrate (Isordil)• isosorbide mononitrate• nitroglycerin

Mechanism of action• The nitrates relax and dilate veins,

arteries, and capillaries, allowing increased blood fl ow through the vessels and lowering systemic blood pressure because of a drop in resistance.

• Nitrates decreases the preload and afterload

INDICATIONS

• LONG ACTING NITRATES Taken before chest pain begins in situations in

which exertion or stress can be anticipated for prevention of angina in adults; taken daily for management of chronic angina

SHORT ACTING NITRATES• Treatment of acute angina attack; prevention of

anginal attacks

AVAILABLE FORMS• Nitroglycerin is available as• sublingual tablet, • Translingual spray, • Intravenous solution• Transdermal patch, • Topical ointmentor paste, • Transmucosal agent

DOSAGE

• Isosorbide nitrate- 2.5–5 mg SL 5-mg chewable tablet; 5–20 mg PO;

• Nitroglycerin- 5 mcg/min via IV infusion pump every 3–5 min; • 0.4-mg metered dose sublingual, up to three

doses in 15 min for acute attack

Contraindications• Hypersensitivity• Severe anemia• Head trauma or cerebral hemorrhage• pregnancy or lactation

Adverse effect

• Central nervous system (CNS) headache, dizziness, and weakness• Gastrointestinal (GI) nausea, vomiting, and incontinence.Cardiovascular Hypotension• Integumentary flushing, pallor, increased perspiration.

Nurses responsibilities

• Assess for contraindications• Assess cardiopulmonary status closely,

including pulse rate, blood pressure, heart rate, and rhythm (30min)

• Always check the expiration date on the bottle and protect the medication from heat and light

• Instruct the patient that a sublingual dose may be repeated in 5 minutes if relief is

is not felt, for a total of three doses; if pain persists, the patient should go to an emergency room•Rotate the sites of topical form•Taper the dose gradually (over 4 to 6 weeks) after long-term therapy

BETA BLOCKERS• Beta-adrenergic blockers are used to

block the stimulatory effects of the sympathetic nervous system.

• Eg- Atenelol Propanalol Metoprolol

Mechanism of action

• The beta-blockers competitively block beta-adrenergic receptors in the heart and decreasing the influence of the SNS on these tissues. The result is a decrease in the excitability of the heart, a decrease in cardiac output, a decrease in cardiac oxygen consumption, and a lowering

of blood pressure.

INDICATIONS

• Long-term management of angina pectoris.

• To prevent reinfarction in stable patients 1 to 4 weeks after an MI

CONTRAINDICATIONS

• Bradycardia, heart block, and cardiogenic shock

• Pregnancy and lactation• Cautious administration to Asthma,

chronic obstructive pulmonary disease, or thyrotoxicosis

DOASGE

• ORAL- 50-100 mg • INTRAVENOUS - 5mg -15mg

NURSES RESPONSIBILITY

• Assess for contraindications or cautions• Do not stop these drugs abruptly after

chronic therapy, but taper gradually over 2 weeks

• Monitor blood pressure, pulse, rhythm, and cardiac output regularly

• Continuously monitor any patient receiving an intravenous form of these drugs

CALCIUM CHANNEL BLOCKERS

• amlodipine (Norvasc),• diltiazem (Cardizem)• nicardipine (Cardene)• nifedipine• verapamil (Calan, Isoptin).

MECHANISM OF ACTION

• Calcium channel blockers inhibit the movement of calcium ions across the membranes of myocardial and arterial muscle cells, altering the action potential and blocking muscle cell contraction.

• This will results loss of smooth muscle tone, vasodilation, and decreased peripheral resistance occur

• Decreases the preload and afterload which results in decreases cardiac workload and oxygen consumption.

INDICATIONSTreatment of •Prinzmetal angina •Chronic angina•Effort associated angina•Hypertension.•Verapamil is also used to treat cardiac tachyarrhythmias because it slows conduction more than the other calcium channel blockers do

Contraindications• Hypersensitivity• Pregnancy and lactationCaution should be used with • heart block or sick sinus syndrome• Renal or hepatic dysfunction• Heart Failure ,

Adverse Effects• CNS -dizziness, light-headedness,

headache, and fatigue. • GI- nausea and hepatic injury related to

direct toxic effects on hepatic cells. Cardiovascular -hypotension, bradycardia, peripheral edema, and heart block.

• Skin- flushing and rash

NURSES RESPONSIBILITIES

• Assess for contraindications• Inspect skin for color and integrity• Monitor blood pressure very carefully• Provide thorough patient teaching

Potassium channel openers

• Potassium channel openers activates the ATP sensitive potassium channels thereby hyperpolarising the vascular smooth muscles.

• This results in reduction in vascular tone • That will lead to a decrease in preload and

afterload• EG- Nicorandil

Dosage

• Oral- 5-20mg

INDICATIONS

• Prevention and long term treatment of chronic stable angina pectoris

• Reduction in the risk of acute coronary syndromes in patients with chronic stable angina

contraindications

• Hypersensitivity • Cardiogenic shock• hypotension

Side effects

• Flushing• Palpitation• Weakness• Headache• Dizziness• vomiting

Nurses responsibility

• Assess the hypersensitivity and contraindications

• Regular monitoring of vital signs • Health education• asses the oral cavity for oral ulcers

OTHERS- IVABRADINE

• Ivabradine is a newer type of drug

• Mechnism of action- it acts by reducing the heart rate by specific inhibition of the funny

channel (cyclic nucleotide-gated)• It specifically inhibits the cardiac

pacemaker and therby reducing heart rate

indications

• Chronic stable angina patients with normal sinus rhythm

• Chronic heart failure

Dosage

• Oral- 2.5-5mg

Contraindications

• Resting heart rate less than 70• Cardiogenic shock• Acute M I• Sick sinus syndrome• Severe hepatic injury• Pregnency and lactation

Side effects

• Blurred vision• Bradycardia• Syncope• Headache• Constipation• Muscle cramps

Nurses responsibility

• Check for hypersensitivity and contraindications

• Assess the pulse rate and blood pressure• Check the liver function test regularly• Check for visual disturbances• Health education

ANTIHYPERTENSIVES

?

HYPERTENSION

•REGULATORS OF BLOOD PRESSURE ?

• Antihypertensives are the drugs that used to treat hypertension

CLASSIFICATIONS• DIURETICS LOOP DIURETICS Eg- furosemide THIAZIDE DIURETICS Eg- Hydrochlorothiazide POTASSIUM SPARING DIURETICS Eg- Spirinolactone

ADRENERGIC inhibitors•CENTRALLY ACTING α- ADRENERGIC ANTAGONISTS Eg- Clonidine•PERIPHERALLY ACTING α- ADRENERGIC ANTAGONISTS Eg- Reserpine• α- ADRENERGIC BLOCKERS Eg-Prazocin

• β- ADRENERGIC BLOCKERS Eg- Atenelol

• Calcium Channel Blockers Eg- Amlodipine Nifidipine

ANGIOTENSIN INHIBITORS• ANGIOTENSIN-CONVERTING ENZYME (ACE) INHIBITORS Eg- Captopril, Enalapril

• Angiotensin II–Receptor Blockers Eg- Losartan Telmisartan

• Vasodilators Eg- Nitroglycerin

• DIRECT VASODILATORS Eg- Nitroglycerin Sodium nitroprusside

DIURETICS

Drugs that increase the production of urine

LOOP DIURETICS

They inhibit the sodium and chloride reabsorption in the thick segment of the ascending limb of the loop of Henle as well as in the proximal convoluted tubule and the distal diluting site

Eg- furosemide( Lasix)

Dosage

• 40 mg PO t.i.d

Thiazide diuretics

Inhibit sodium and chloride reabsorption in the distal convoluted tubule

•These drugs are the first-line drugs used to manage essential hypertension when drug therapy is needed

• Eg- Hydrochlorothiazide

• Dosage- 25–100 mg/d

Potassium Sparing Diuretics

• The potassium-sparing diuretics are not as powerful as the loop diuretics, but they retain potassium instead of wasting it

• Eg- spironolactone (Aldactone) amiloride (Midamor)

Mechanism of action

• Spironolactone acts as an aldosterone antagonist, blocking the actions of aldosterone in the distal tubule.

• It decreases the elimination of potassium

Dosage

• 50–100 mg/d PO

CONTRAINDICATIONS

• Hypersensitivity• Fluid and electrolyte imbalances• Severe renal failure cautious administration with Systemic lupus erythematous( SLE) Gout Pregnancy and lactation

SIDE EFFECTS

• Common side effects GI upset fluid and electrolyte imbalances hypotension electrolyte disturbances

• Side effects ( thiazide and loop diuretics) 1.hypokalemia weakness, muscle cramps, and arrhythmia 2. hypercalcemia 3. decreased excretion of uric acid

• Side effects ( potassium sparing diuretics) 1. Hyperkalemia lethargy, confusion, ataxia, muscle cramps, and cardiac arrhythmias.