These drugs include a heterogeneous class of compounds which act by preventing the entry of slow calcium ions into the cellos which are required for the contraction of muscles. These drugs act on the calcium channel receptors and cause blockade of the calcium channels.

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Surendra Kumar
Assistant Professor
KNIMT, Faculty of Pharmacy, Sultanpur
CALCIUM CHANNEL
BLOCKERS

2.  Calcium channel blockers lower your blood pressure by preventing calcium
from entering the cells of your heart and arteries. Calcium causes the heart
and arteries to contract more strongly.
 By blocking calcium, calcium channel blockers allow blood vessels to relax
and open.
 Some calcium channel blockers have the added benefit of slowing your
heart rate, which can further lower your blood pressure, relieve chest pain
(angina) and control an irregular heartbeat. Calcium channel blockers are also
called calcium antagonists.
 Calcium channel blockers are available in short-acting and long-acting
forms. Short-acting medications work quickly, but their effects last only a few
hours.
 Long-acting medications are slowly released to provide a longer lasting
effect.
CALCIUM CHANNEL BLOCKERS

3. Examples of calcium channel blockers include:
Amlodipine (Norvasc)
Diltiazem (Cardizem, Tiazac, others)
Felodipine
Isradipine
Nicardipine
Nifedipine (Adalat CC, Procardia)
Nisoldipine (Sular)
Verapamil (Calan, Verelan)
Calcium channel blockers:
Calcium channel antagonists or calcium antagonists are a group of
medications that disrupt the movement of calcium through calcium channels.
Calcium channel blockers are used as antihypertensive drugs, i.e., as
medications to decrease blood pressure in patients with hypertension.

4. VERAPAMIL
IUPAC Name: 2-(3, 4-dimethoxyphenyl)-5-[2-(3, 4-
dimethoxyphenyl)ethyl-methylamino]-2-propan-2-ylpentanenitrile

5.  Inhibition of calcium influx prevents the contraction of vascular smooth
muscle, causing relaxation/dilation of blood vessels throughout the
peripheral circulation - this lowers systemic vascular resistance (i.e.
afterload) and thus blood pressure.
 This reduction in vascular resistance also reduces the force against which
the heart must push, decreasing myocardial energy consumption and
oxygen requirements and thus alleviating angina.
 Electrical activity through the AV node is responsible for determining
heart rate, and this activity is dependent upon calcium influx through L-type
calcium channels.
 By inhibiting these channels and decreasing the influx of calcium,
verapamil prolongs the refractory period of the AV node and slows
conduction, thereby slowing and controlling the heart rate in patients with
arrhythmia.
MECHANISM OF ACTION

6. USES
Verapamil is used to treat high blood pressure and to
control angina (chest pain).
It is also used to treatment cerebral vasospasm and in cluster headache.
BEPRIDIL HYDROCHLORIDE
IUPAC Name: N-benzyl-N-
[3-(2-methylpropoxy)-2-
pyrrolidin-1-ylpropyl] aniline;
hydrochloride

7.  Bepridil has inhibitory effects on both the slow calcium (L-type) and fast
sodium inward currents in myocardial and vascular smooth muscle, interferes
with calcium binding to calmodulin, and blocks both voltage and receptor
operated calcium channels.
 Bepridil inhibits the transmembrane influx of calcium ions into cardiac and
vascular smooth muscle.
This has been demonstrated in isolated myocardial and vascular smooth
muscle preparations in which both the slope of the calcium dose response
curve and the maximum calcium-induced inotropic response were
significantly reduced by bepridil.
MECHANISM OF ACTION

8. USES
Bepridil (trade name Vascor) is an amine calcium channel blocker once used to
treat angina.
DILTIAZEM HYDROCHLORIDE
IUPAC Name: [(2S, 3S)-5-[2-
(dimethylamino)ethyl]-2-(4-
methoxyphenyl)-4-oxo-2,3-
dihydro-1,5-benzothiazepin-3-yl]
acetate; hydrochloride

9.  Diltiazem inhibits the inflow of calcium ions into the cardiac smooth
muscle during depolarization. Reduced intracellular calcium concentrations
equate to increased smooth muscle relaxation resulting in arterial
vasodilation and, therefore, decreased blood pressure.
Diltiazem is a potent coronary artery vasodilator and is consequently
used for chronic angina and in those patients with coronary vasospasm.
Vasospasm of the coronary arteries can lead to debilitating conditions such
as myocardial infarction.
MECHANISM OF ACTION
USES
Diltiazem is used to treat hypertension (high blood pressure), angina (chest
pain), and certain heart rhythm disorders.

10. NIFEDIPINE
IUPAC Name: dimethyl 2, 6-
dimethyl-4-(2-nitrophenyl)-1, 4-
dihydropyridine-3, 5-
dicarboxylate

11. Nifedipine blocks voltage gated L-type calcium channels in vascular
smooth muscle and myocardial cells.
 This blockage prevents the entry of calcium ions into cells during
depolarization, reducing peripheral arterial vascular resistance and dilating
coronary arteries.
These actions reduce blood pressure and increase the supply of oxygen to
the heart, alleviating angina.

12. USES
It is used in management of hypertension. It has no antiarrhythmic activity.
This medication is used to prevent certain types of chest pain (angina). It
may allow you to exercise more and decrease the frequency of angina
attacks.
AMLODIPINE

13. MECHANISM OF ACTION
Amlodipine is an angioselective calcium channel blocker and inhibits the
movement of calcium ions into vascular smooth muscle cells and cardiac
muscle cells which inhibits the contraction of cardiac muscle and vascular
smooth muscle cells.

14. USES
Amlodipine is used to treat chest pain (angina) and other conditions caused
by coronary artery disease.
Amlodipine is also used to treat high blood pressure (hypertension).
FELODIPINE
IUPAC Name: 5-O-ethyl 3-O-
methyl 4-(2,3-dichlorophenyl)-
2,6-dimethyl-1,4-dihydropyridine-
3,5-dicarboxylate

15. MECHANISM OF ACTION
It acts primarily on vascular smooth muscle cells by stabilizing voltage-
gated L-type calcium channels in their inactive conformation.
 By inhibiting the influx of calcium in smooth muscle cells, felodipine
prevents calcium-dependent myocyte contraction and vasoconstriction.
USES
Felodipine is used to treat high blood pressure and stable angina.
It should not be used for people who are pregnant, have acute heart failure,
and are having a heart attack, have an obstructed heart valve, or have
obstructions that block bloodflow out of the heart.

16. NICARDDIPINE
IUPAC Name: 5-O-[2-[benzyl
(methyl) amino] ethyl] 3-O-methyl
2, 6-dimethyl-4-(3-nitrophenyl)-1,
4-dihydropyridine-3, 5-
dicarboxylate; hydrochloride
MECHANISM OF ACTION
 Nicardipine hydrochloride capsules are a calcium entry blocker (slow
channel blocker or calcium ion antagonist) that inhibits the transmembrane
influx of calcium ions into cardiac muscle and smooth muscle without
changing serum calcium concentrations.

17.  The contractile processes of cardiac muscle and vascular smooth muscle
are dependent upon the movement of extracellular calcium ions into these
cells through specific ion channels.
 The effects of Nicardipine hydrochloride capsules are more selective to
vascular smooth muscle than cardiac muscle.
USES
Nicardipine is used to treat hypertension (high blood pressure) and angina
(chest pain).

18. NIMODIPINE
IUPAC Name: 3-O-(2-methoxyethyl) 5-O-propan-2-yl 2,6-dimethyl-
4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

19. MECHANISM OF ACTION
 During the depolarization of smooth muscle cells of blood vessels, there is
an influx of calcium ions.
 The primary function of nimodipine is to block voltage-gated L-type
calcium channels in their inactive conformation, avoiding this influx, to
prevent vasoconstriction.
 It has a preference to act on cerebral blood vessels since it is lipophilic and
can cross the blood-brain barrier.

20. USES
Nimodipine is used to decrease problems due to a certain type of bleeding in
the brain (subarachnoid hemorrhage-SAH).
Nimodipine is called a calcium channel blocker. The body naturally responds
to bleeding by narrowing the blood vessel to slow blood flow. However,
when the bleeding is in the brain, stopping blood flow causes more brain
damage. Nimodipine is thought to work by relaxing narrowed blood vessels
in the brain near the area of bleeding so blood can flow more easily.

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