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DRUGS ACTING ON CVS
Presented by
Dr. Sannithi Nagarjuna
Coordinator for RIPER-GPAT Cell,
Hyderabad Academy &
Online GPAT Academy
7899107907
9885784793
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❑ The cardiovascular system refers to the heart, blood vessels and the
blood.
❑ Blood contains oxygen and other nutrients which your body needs to
survive.
❑ The body takes these essential nutrients from the blood. At the same
time, the body dumps waste products like carbon dioxide, back into the
blood, so they can be removed.
❑ The main function of the cardiovascular system is therefore to maintain
blood flow to all parts of the body, to allow it to survive.
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The major functions of the cardiovascular system are
❖ To transport nutrients, gases and waste products around
the body.
❖ To protect the body from infection and blood loss.
❖ To help the body maintain a constant body temperature
('thermoregulation')
❖ To maintain fluid balance within the body.
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HEART
❖ The heart is a muscular organ which
pumps blood through the blood vessels of
the circulatory system. The pumped blood
carries oxygen and nutrients to the body.
❖ The heart is a muscular organ about the size of a fist.
❖ It is a very strong muscle. It is on the left side of the
body in humans.
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BLOOD VESSELS
❖ The blood vessels are the components of the circulatory system
that transport blood throughout the human body.
❖ These vessels transport blood cells, nutrients, and oxygen to the
tissues of the body.
❖ They also take waste and carbon dioxide away from the tissues.
Blood vessels are needed to sustain life, because all of the
body's tissues rely on their functionality.
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There are two types of blood vessels
1. Coronary Blood Vessels
Which supply blood to Heart
2. Peripheral Blood Vessels
Which supply blood to various parts of the body
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DISORDERS RELATED TO CVS
1. CONGESTIVE HEART FAILURE/
CONGESTIVE CARDIAC FAILURE (CHF/CCF)-
❖Where the heart is unable to pump sufficient blood to
various parts of the body.
❖ As a result of this condition blood supply decreases to
various parts of the body.
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Source: Google
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2. ATHEROSCLEROSIS
❖ It is characterized by deposition of lipids and lipid
related materials like cholesterol, triglycerides and
lipoproteins in blood vessels specially coronary blood
vessels.
❖ As a result of this condition blood supply decreases to
heart.
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Source: Google
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3. ANGINA PECTORIS
It is characterized by the development of pain in the chest due to
decreased blood/oxygen supply to muscle of the heart (Myocardium)
—Myocardial ischemia/ Myocardial hypoxia.
One of the main reason for angina pectoris is Atherosclerosis.
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Source: Google
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4. MYOCARDIAL INFARACTION
It is a death of the myocardium due to decreased/loss of
blood/oxygen supply to muscle of the heart (Myocardium) for long
period of time.
One of the main reason for myocardial infaraction is angina
pectoris.
It is otherwise called as heart attack.
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Source: Google
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5. HYPERTENSION
Increase in blood pressure
6. HYPOTENSION
Decrease in blood pressure
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Source: Google
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7. ARRHYTHMIAS
Irregular or abnormal heart beat
Abnormal heart rhythm
Heart beat may be increases or decreases
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ELECTROPHYSIOLOGY OF
CARDIAC CELL
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IMPULSE/ACTION POTENTIAL GENERATION IN
CARDIAC CELL
❖ Resting membrane potential for cardiac cell is -90 mV.
❖ Action potential/ impulse generation begins with the
opening of sodium channels.
❖ Due to opening of sodium channels influx of sodium
ions will take place as a result potential will be
increases (Phase 0).
❖ Sodium ions enter into the cell at a very faster rate of
107 ions/sec.
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❖ After some time sodium channels will be closed and
potassium channels will be opened because of which
potential will be decreases (Phase 1).
❖ After some time opening of calcium channels will take place
when potassium channels are in open state as a result influx
of calcium and efflux of potassium ions take place, so there
is no change in the potential and called as Plateu Phase
(Phase 2).
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❖ After some time, Calcium channels will be closed and only
opening of potassium channels hence there is continuous
efflux of potassium ions and potential will be decreases
(Phase 3).
❖ At this stage sodium is present inside and potassium is
present outside and finally there is an activation of the
enzyme Na+ K+ ATPase which will keep potassium inside
and sodium out side, cell reaches resting state (Phase 4).
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Source: Google
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PHASES OF ACTION POTENTIAL
Phase 0 –Due to opening of sodium channels
Phase 1 –Due to opening of potassium channels
Phase 2 –Due to opening of calcium channels
Phase 3 –Due to opening of potassium channels
Phase 4 –Due to activation of Na+ K+ ATPase
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IMPULSE PROPAGATION/CONDUCTION
IN CARDIAC CELL
AUTOMATICITY
❖ Capacity to generate action potential on its own without
any external stimulus called as automaticity.
❖ SA Node is having the property of automaticity.
❖ Hence SA Node is otherwise called as Pace Maker of the
cardiac cell.
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SA NODE
ATRIA
AV NODE
BUNDLE OF HIS
PURKINJE FIBRES
VENTRICLES
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Source: Google
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ECG/EKG/ELECTROCARDIOGRAM
Source: Google
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ARRHYTHMIAS
Mean abnormal heart beat or irregular heart beat.
Heart beat may be increases or decreases.
Normal heart beat is 72 beats/minute
Normal heart beat range is 60-100 beats/minute
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Which are of 2 types
1. Tachyarrhythmias
Above 100 beats/minute
2. Bradyarrhythmias
Below 60 beats/minute
Most of the patients are suffering from
tachyarrhythmias
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TACHYARRHYTHMIAS
Reasons include
1. Increased impulse generation in SA node due
to increased activity of Sympathetic Nervous
System
2. Fast impulse conduction i.e. time required for
impulse conduction decreases
3. Ecotopic foci i.e. Apart from SA node other
parts also exhibit the property of automaticity
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BRADYARRHYTHMIAS
Reasons include
1. Decreased impulse generation in SA node due to
increased activity of Parasympathetic Nervous System
2. Slow impulse conduction i.e. time required for impulse
conduction increases
3. Heart Block i.e. Blockade in any part of the cardiac cell
results in failure of impulse conduction to the
ventricles that result in decreased heart beat
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ANTIARRHYTHMICS
Which are used for the treatment of arrhythmias
preferably for the treatment of tachyarrhythmias.
They are classified into:
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CLASS I DRUGS -- Sodium Channel Blockers
CLASS II DRUGS -- β Blockers
CLASS III DRUGS – Potassium Channel Blockers
CLASS IV DRUGS – Calcium Channel Blockers
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CLASS I DRUGS
They are further classified into 3 types
Ia --- Quinidine, Procainamide, Disopyramide
Ib --- Lignocaine, Tocainide, Phenytoin
Ic --- Flecainide, Propafenone, Moricizine
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Ia --- Intermediate association/dissociation
Ib --- Fast association/dissociation
Ic --- Slow association/dissociation
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Onset of action is in the order of
Ib > Ia > Ic
Duration of action is in the order of
Ic > Ia > Ib
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Quinidine – It is an alkaloid obtained from
Cinchona bark. In higher doses it causes
cinchonism characterized by tinnitus.
Procainamide – It is an amide derivative of
local anesthetic drug Procaine.
Disopyramide – Which produces
anticholinergic side effects
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Lignocaine- Which undergoes high first pass
metabolism.
Not suitable for oral and given by IV route. Also used
as local anesthetic agent.
Tocainide - Oral route
Phenytoin – Also used as Antiepileptic agent
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Therapeutic uses of sodium channel
blockers
1. Antiepileptics
2. Antiarrhythmics
3. Local anesthetics
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CLASS II DRUGS
They are classified into 2 types
1. Nonselective β blockers
Ex: Propranolol, Pindolol, Timolol, Sotalol
2. Selective β1 blockers
Ex: Atenolol, Acebutalol, Bisoprolol, Nebivolol
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CLASS III DRUGS
Ex: Bretylium, Amiodarone, Sotalol
Sotalol which acts as both class II and class III
drug.
Amiodarone is an iodine containing drug which
causes bluish-grey colour to the urine.
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CLASS IV DRUGS
Ex: Verapamil, Diltiazem
Dihydropyridines like Amlodipine, Nifedipine,
Nimodipine, Nitrendipine block calcium channels
in blood vessels but not in heart.
Hence they are not used for the treatment of
arrhythmias.
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DRUGS USED FOR BRADYARRHYTHMIAS
1. Anticholinergics
Ex: Atropine
2. Sympathomimetics (Selective β1 receptor
agonists)
Ex: Dobutamine
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DRUGS FOR CONGESTIVE HEART
FAILURE/CONGESTIVE CARDIAC FAILURE
(CARDIOTONICS)
❖ Congestive heart failure is a condition where the heart
is unable to pump sufficient blood to various parts of
the body.
❖ As a result of this condition blood supply decreases to
various parts of the body.
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Source: Google
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The right and left sides of the heart work together.
The pattern described below is repeated over and over
(heart rhythm), causing blood to flow continuously to the
heart, lungs, and body to supply oxygen and nutrients to
the body cells and to deliver waste products to organs that
remove them from your body.
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Right side of the heart
❖ Blood enters the heart through two large veins, the inferior and
superior vena cava, emptying oxygen-poor blood from the body
into the right atrium of the heart.
❖ As the atrium contracts, blood flows from your right atrium into
your right ventricle through the open tricuspid valve.
❖ When the ventricle is full, the tricuspid valve shuts. This prevents
blood from flowing backward into the atria while the ventricle
contracts.
❖ As the ventricle contracts, blood leaves the heart through the
pulmonic valve, into the pulmonary artery and to the lungs where
it is oxygenated. Note that oxygen-poor or CO2 containing blood
goes through the pulmonary artery to the lungs where CO2 is
exchanged for O2.
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Left side of the heart
(operating at the same time as the right side of the heart)
❖ The pulmonary vein empties oxygen-rich blood from the lungs into the
left atrium of the heart.
❖ As the atrium contracts, blood flows from your left atrium into your left
ventricle through the open mitral valve.
❖ When the ventricle is full, the mitral valve shuts. This prevents blood
from flowing backward into the atrium while the ventricle contracts.
❖ As the ventricle contracts, oxygen-enriched blood leaves the heart
through the aortic valve, into the aorta and to the arteries and
eventually into veins to complete the blood circulation in your body.
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Source: Google
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SYMPTOMS IN CHF
❖ Fatigue (Tiredness)- Decrease in blood supply to all
parts of the body
❖ Dyspnea (Breathlessness)- accumulation of blood in
lungs
❖ Heart congestion- accumulation of blood in heart
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TREATMENT OF CHF
Heart Contractions/Heart Beat
1. No. of Contractions
2. Force of Contraction
To treat CHF we have to increase the force of contraction
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Force of contraction depends upon the availability of
calcium and cAMP.
So mechanisms of drugs used for CHF include
I. Drugs which increase the levels of Calcium
II. Drugs which increase the levels of cAMP
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DRUGS WHICH INCREASE THE
LEVELS OF CALCIUM
CARDIAC GLYCOSIDES
Ex: Digitalis
Stropanthus
Squill
Thevetia
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Digitalis ---
Digitalis purpurea (Digitoxin)
Digitalis lanata (Digoxin)
Stropanthus ----
Stropanthus kombe (K-Stropanthin)
Stropanthus gratus (G-Stropanthin/Ouabain)
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MECHANISM OF ACTION OF
CARDIAC GLYCOSIDES
Which act by inhibiting Na+ K+ ATPase thereby they increase
the intracellular levels of sodium which increase the
intracellular levels of calcium by which they increase the force
of contraction.
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Source: Google
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Source: Google
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PHARMACOLOGICAL ACTIONS
OF CARDIAC GLYCOSIDES
1. INOTROPIC ACTION ( FORCE OF CONTRACTION)
They increase the force of contraction by increasing calcium hence
Positive Inotropic action
2. CHRONOTROPIC ACTION (NO OF CONTRACTIONS)
They decrease the number of heart betas by vagus nerve stimulation
and by increasing refractory period hence Negative Chronotopic action
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PHARMACOKINETICS OF
CARDIAC GLYCOSIDES
1. Which are highly plasma protein bound drugs hence they have
2. Which are having very narrow therapeutic index hence they are
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1. Which are highly plasma protein bound drugs
hence they have very longer duration of action
2. Which are having very narrow therapeutic
index hence they are highly toxic
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SIDE EFFECTS OF CARDIAC
GLYCOSIDES
1. Hypokalemia
2. Cumulative toxicity
3. Visual disturbances
4. Nausea and vomiting
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DRUG INTERACTIONS OF
CARDIAC GLYCOSIDES
1. Cardiac glycosides + Diuretics -→ Severe Hypokalemia
2. Cardiac glycosides + Quinidine -→ Toxicity
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THERAPEUTIC USES OF CARDIAC
GLYCOSIDES
1. For the treatment of CHF
(due to Positive Inotropic action)
2. For the treatment of tachyarrhythmias like tachycardia,
flutter and fibrillation
(due to Negative Chronotopic action)
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TOXICITY TREATMENT
1. DIGIBIND- a specific antidote
2. Potassium supplements
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DRUGS WHICH INCREASE THE
LEVELS OF CAMP
ADENYL CYCLASE PATHWAY
ATP -------------→ cAMP -----------→ Inactive
❖ cAMP acts as a second messenger
❖ Enzyme Phosphodiesterase involved in the inactivation of
cAMP
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1. Sympathomimetics (Selective β1 receptor agonists)
Ex: Dobutamine
2. Phosphodiesterase inhibitors
Phosphodiesterase III present in heart and
Phosphodiesterase IV present in bronchi.
Selective Phosphodiesterase III inhibitors
Ex: Amrinone, Milrinone
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Presented by
Dr. Sannithi Nagarjuna
Coordinator for RIPER-GPAT Cell,
Hyderabad Academy &
Online GPAT Academy
7899107907
9885784793