2. The drugs acting on the cardio vascular system are
Divided into four groups are:
1) Cardio tonic drugs
2)Anti hypertensive drugs
3) Anti arrhythmic drugs
4)Anti anginal drugs
3. 1) CARDIOTONIC DRUGS
Drugs which increase the force of contraction of
the heart are called cardio tonic drugs.
CLASSIFICATION:
1)CARDIAC GLYCOSIDES -Digoxin
2)SYMPATHETIC DRUG -Adrenaline
3)ANTICHOLINERGIC DRUGS -Atropine
4)XANTHINES -Theophylline
Cardiac glycosides are those glycosides which
have specific action to the failing heart.
4.
DIGITALIS
DIGITALIS is a powerful inhibitor of Na+/k+
ATP ase .
As a result they increase the efficiency of failing
heart increasing Na+ concentration within cell
membrane ;which enhances Ca ++ availability to the
contractile apparatus and increase the contractility
5. MECHANISM OF ACTION :
It alters ion transport system by inhibiting the
membrane bound enzyme Na+ / K+ ATP ase which
is associated with Na+ pump
INDICATION OF DIGITALIS:
Congestive heart failure due to ischemia,
hypertensive or valvular heart disease
Atrial fibrillation
Left ventricular failure
6. 2) ANTI HYPERTENSIVE DRUGS
HYPERTENSION: Persistent rise of blood pressure
above the upper limits of normal level according to
the age and sex of an individual is called
HYPERTENSION(HTN)
Normal limits of blood pressure:
Systolic: 100-140 mm Hg
Diastolic :60-90 mm Hg
Alpha Methyl Dopa is useful in treatment of mild
to moderately severe hypertension.
It reduces the BP chiefly by reducing peripheral
vascular hypertension
7. CLONIDINE
It is centrally acting in sympatholytic agent and
acts by decreasing central sympathetic activity
MECHANISM OF ACTION:
It combines with alpha receptors of lower
brainstem which in turn inhibits release of nor
adrenaline from the neurons.
It decreases symphathetic activity which results in
decreased cardiac output due to increase heart
rate and relaxation of capacitance vessels .
Thus BP is decreased
9. 3) ANTI ARRHYTHMIC DRUGS
CARDIAC ARRHYTHMIAS:
The disorder in rate and rhythm of cardiac
contraction due to myocardial damage is known as
cardiac arrhythmias
Cardiac arrhythmias consist of cardiac
depolarizations that deviate from the normal in
one or more aspects;
Abnormality at site of origin of impulse
Its rate and regularity
Its conduction
10. QUINIDINE
It is a class -1 anti arrhythmic drug. It is an
optical isomer of quinine( anti malarial drug)
PHARMACOKINETICS:
-Orally active
-Half life :4-6 hrs
-Metabolised by liver
-Excretion: unchanged fraction by kidney
11. ADVERSE EFFECTS:
1)Heart block
2)Sinus arrest
3)Myocardial depression
4)Nausea
5)Vomitting
INDICATION:
As anti – arrhythmic used in atrial fibrillation
and flutter
Also an anti – malarial
Anti -pyretic
12. 4)ANTI ANGINAL DRUGS
ANGINA PECTORIS:
It is a clinical syndrome characterized by pre
cardiac pain or discomfort due to myocardial
ischemia, which is precipitated by exercise and
relief by rest or sublingual nitro -glycerine
It occurs when coronary blood flow is
insufficient to meet the metabolic recquirement of
the heart muscle
Myocardial oxygen demand mainly depends on
1)Preload
2)After load and
3)Heart rate
13. ORGANIC NITRATES
Glyceryl trinitrate is a short acting
Undergoes 1 st pass metabolism if given orally
Duration:20 -30 mins
Used in mainly acute attack
Orally given
14. MECHANISM OF ACTION
Organic nitrates act by relaxing smooth muscles of
blood vessels. It occurs in following steps:
Denitration of organic nitrates
Reduces intracellular calcium concentration
Relaxation of vascular smooth muscles
Activation of guanylyl cyclase
