5. Nitrates are vasodilators.
Nitrates act directly on smooth muscles and
produce relaxation.
Commonly used nitrate is nitroglycerine
(GTN).
6. Short acting nitrates
Used to terminate acute attack of angina
Eg: Nitroglycerin (GTN)
Long acting nitrates
Used to prevent an attack of angina
Eg: isosorbide dinitrate, isosorbide
mononitrate, pentaerythritol tetranitrate
7. In the smooth muscles nitrates are converted to
nitric oxide.
This nitric oxide activates vascular guanylyl
cyclase (GC) which in turn increases the
synthesis of cGMP (Cyclic guanosine
monophosphate).
This cGMP causes sequestration of Ca2+ , which
is responsible for relaxation of the smooth
muscles.
Results in vasodilation.
8. Vasodilation
Relax vascular smooth muscle
Relaxation of smooth muscles
cGMP causes sequestration of Ca2+
Increases the synthesis of cGMP
Activates vascular guanylyl cyclase
Nitrates converted to nitric oxide
10. 1. Reduction of preload
2. Reduction of afterload
3. Coronary dilation
4. Other actions
1. Dilation of other vasculature
2. Relaxation of other smooth muscles
3. Effects on platelets.
11. Nitrates are vasodilators.
1. Reduction of preload
Venodilation reduces
venous return to the heart
thereby reduce preload.
2. Reduction of afterload
Arteriolar dilation reduces
vascular resistance thus
decrease afterload
3. Coronary dilation
Nitrates cause coronary vasodilation, thus relieves
vasospasm and increases coronary blood flow.
As both preload and afterload are reduced,
workload of the heart is decreased, thereby
reducing oxygen requirement of the heart.
12. 4. Other actions
Dilation of other vasculature
• Dilation of blood vessels in
skin results in flushing.
• Dilation of meningeal
vessels results in headache.
Relaxation of other smooth
muscles
Nitrates relax the bronchial,
gastrointestinal and
genitourinary smooth muscles
for a short period.
Effects on platelets
Nitric oxide from nitrates inhibits platelet aggregation.
13. Nitrates are available for oral, Sublingual, spray
parenteral, ointment and transdermal patch.
Nitrates are well-absorbed orally, but they
undergo extensive first pass metabolism.
So the oral bioavailability of nitrate is poor.
Sublingual route is preferred in case of
emergency for rapid absorption and better
bioavailability.
Sublingual tablets acts within 1-2 minutes
whereas Sublingual spray acts faster than tablets.
16. Headache (common)
Flushing of face
Nausea and vomiting
Sweating
Tachycardia
Palpitation
Weakness
Postural hypotension
Rashes
Contact dermatitis
Local hypersensitivity reaction
for topical use
17. Exertional angina
Acute anginal attacks :
▪ Sublingual nitroglycerin
▪ Drug of choice for acute anginal attacks.
▪ Relieves pain in 2 to 5 minutes.
▪ If the pain is not relieved, the dose is repeated-upto 3 tablets in 15
minutes.
Prophylaxis of angina
▪ NTG can be used for chronic prophylaxis.
▪ Longer acting nitrates are preferred.
▪ Nitroglycerin ointment orTransdermal patch may be used.
18. Vasospastic angina
Unstable angina
Acute coronary syndrome
Cardiac failure
Myocardial infarction
Cyanide poisoning
Nitrates are life saving in cyanide poisoning.
Amylnitrite is given by inhalation and sodium
nitrite by IV injection (10 ml of 3% solution). Then
Sodium thiosulphate is given IV (50 ml of 25%
solution).
19. Role of nitrates in cyanide poisoning.
Nitrates (Amylnitrite and sodium nitrite) convert
hemoglobin into methemoglobin, which has high
affinity for cyanide and forms cyano-
methemoglobin.
Cyano-methemoglobin reacts with Sodium
thiosulphate to form thiocyanate which is easily
excreted by the kidneys.
20. Relieve esophageal spasm
Sublingual NTG is taken just before meals to
counter the spasm.
Relieve biliary colic
Sublingual NTG is also useful as a spasmolytic.
21. Monitor BP before and after administration.
Nitroglycerine is sensitive to light, heat and
moisture, so stored in tightly closed amber
colored glass bottles.
Give sublingual preparations under the tongue
or in the buccal pouch.
Nitroglycerine IV preparation is mixed in 5%
Dextrose Injection or 0.9% Sodium Chloride.
Instruct the patient that a sublingual dose may
be repeated in 5 minutes if pain is not relieved,
for a total of 3 doses.
23. Calcium channel blockers (CCBs) are the
drugs that disrupt calcium movement by
blocking voltage-dependent Ca2+ channels
used to treat angina and supraventricular
tachydysrhythmias as well as hypertension.
Also known as calcium antagonists.
25. Decrease myocardial contraction, Decrease heart rate and AV conduction
velocity, also cause Vascular smooth muscle relaxation
Decrease calcium entry into cardiac and smooth muscle cells
Block L-type calcium channels
Calcium channel blockers
26. Cardiac and smooth muscle
cell contraction depends
upon the activation of
calcium channels in the
cardiac myocytes. For
depolarization of cardiac and
other smooth muscles cells,
entry of calcium into the cells
occurs through these calcium
channels. This calcium
triggers the release of
intracellular calcium from
sarcoplasmic reticulum.
27. On vascular smooth muscles and Coronary
circulation
On other smooth muscles
On heart
29. Dihydropyridine CCBs have prominent effect
on blood vessels.
Nimodipine crosses the blood brain barrier
and relaxes the cerebral blood vessels.
On other smooth muscles
Relax GI and bronchial smooth muscles
Relax uterus, so used in premature labor.
32. CCBs are well-absorbed orally but undergo
extensive first pass metabolism.
They are metabolized in the liver.
Excreted through kidneys.
Onset of action is in 30-60 minutes after oral
administration while on IV use the action is
quick.
33. 1. Verapamil
Decrease heart rate (negative chronotropic effect)
Decrease force of myocardial contraction (negative
ionotropic effect)
DecreaseAV conduction
Vasodilator effect of verapamil is less potent.
Used in arrhythmia and angina.
Dose: 40-160 mgTDS orally and 5 mg by slow IV
inj.
Adverse effects
Nausea
Constipation
Bradycardia
Heart block
Hypotension
Skin rashes
34. 2. Diltiazem
Decrease heart rate (negative chronotropic
effect)
Decrease force of myocardial contraction
(negative ionotropic effect)
Vasodilator effect is less potent.
Dose: 30-60 mgTDS orally.
Adverse effects –same as verapamil.
35. 3. Nifedipine
Potent vasodilator and causes a significant fall in
BP and evokes reflex tachycardia.
Myocardiac depressant effect is weak
It can be given orally or sublingually. Patches also
Dose: 5-20 mg BD
Adverse effects
Headache
Flushing
Palpitation
Dizziness
Fatigue
Hypotension
Leg cramps
Ankle edema
Long-term use : gum hypertrophy
36. 3. Nimodipine
Crosses the blood brain barrier and relaxes
the cerebral blood vessels.
Used in haemorrhagic stroke and
subarachnoid haemorrhage.
Dose: 30-60 mg QID.
37. 4. Amlodipine, felodipine, nitrendipine,
nicardipine
High vascular effects.
Long acting CCBs.
Can be given once daily.
Useful HTN.
38. Angina pectoris
As prophylaxis for exertional angina
▪ Verapamil and diltiazem for prophylaxis
Variant angina
Vasospastic angina
▪ Verapamil and amlodipine are preferred
Unstable angina
▪ Verapamil is used
Dihydropyridine CCBs like amlodipine with beta
blockers for long term management.
40. Peripheral vascular disease
Nifedipine, felodipine and diltiazem can be used in
Raynaud's disease.
Migraine
Prophylaxis- verapamil is useful
Hypertrophic cardiomyopathy
Verapamil is useful
Subarachnoid hemorrhage and haemorrhagic
stroke
Nimodipine is useful.
Preterm labor
Nifedipine is useful.
41. Verapamil and diltiazem should be avoided
in patients receiving beta-adrenergic blockers
because the myocardiac depressant effects
get added up.
Verapamil can precipitate digoxin toxicity by
increasing digoxin levels (verapamil reduces
digoxin excretion).
44. Beta blockers are the drugs that block beta
receptors thereby inhibiting the actions of
sympathetic stimulations (catecholamines).
Beta antagonist.
46. 1. Nonselective
Blocks both β1 and β2 receptors.
2. Cardioselective (β1)
Blocks cardiac specific β1 receptors. β2 receptor
blockade is weak.
3. Partial agonists
Have some sympathomimetic action due to partial β
agonist property.
4. With additional alpha blocking property
Blocks both α and β (β1 and β2) receptors.
5. β1 blocker β2 agonist
Blocks only cardiac specific β1 receptors.
48. Reduce cardiac workload
Reduce myocardial O2 demand
Decrease heart rate, Decrease force of contraction,
Decrease cardiac output, Decrease BP, Delay AV conduction
Inhibit sympathetic (catecholamines) stimulations
Blocks beta receptors
50. CVS
Act as cardiac depressant
Decrease heart rate (negative chronotropic effect)
Decrease force of contraction (negative ionotropic effect)
Decrease cardiac output
Decrease BP
Delay AV conduction (negative dromotropic effect)
Reduce myocardial O2 demand
Reduce cardiac workload.
Improve exercise tolerance in angina patients.
51. Respiratory tract
Blockade of B2 receptors in the bronchial smooth
muscle causes increase in airway resistance.
May precipitate acute attack in asthmatics.
Eye
Reduce intraocular pressure by decreased secretion of
aqueous humor.
Metabolism
β-antagonists block lipolysis & glycogenolysis – cause
rise in plasma free fatty acid and triglyceride.Also
interfere with recovery from hypoglycemia in diabetics
52. Well absorbed orally.
Given intravenously in emergencies.
Low oral bioavailability due to extensive first
pass metabolism.
Highly lipid soluble, so crosses blood brain
barrier.
Metabolized in the liver.
Excreted through kidneys.
53. Bradycardia (common)
CCF
Acute pulmonary edema
Cold extremities (in patients with peripheral vascular
disease)
Acute asthmatic attack (in asthmatics)
CNS
Insomnia
Depression
Halluçination (rare)
Fatigue, weakness
Decrease exercise capacity
Rebound hypertension and anginal attacks
Due to abrupt withdrawal of B-blockers after prolonged use.
54. Hypertension
As first line drugs in mild to moderate hypertension
Used alone or with other antihypertensives.
Angina pectoris
Long term prophylaxis of exertional angina and
classical angina.
Cardioselective drugs are preferred than non
selective drugs.
Have to take on regular basis.
Cardiac arrnythmias
For both supraventricular & ventricular arrhythmias
55. Myocardial infarction
Given IV infusion in acute MI to limit the size of
infarct.
Long-term treatment prolongs survival.
Congestive cardiac failure
Obstructive cardiomyopathy
Pheochromocytoma
Propranolol is given before surgery to control
hypertension.
56. Thyrotoxicosis
Propranolol controls palpitation, tremors and affords
symptomatic relief in thyrotoxicosis.
Used as adjuvant.
Also useful in thyrotoxic crisis.
Glaucoma
Timolol is used topically in open angle glaucoma.
Migraine
As prophylaxis.
Propranolol is used.
Anxiety
Propranolol prevents the acute panic symptoms
58. Atenolol
Cardioselective
Longer acting-given once daily
Less lipid soluble-does not cross BBB-hence no CNS
side effects
No side effects on lipid profile. Hence very
commonly used
Dose: 25-100 mg daily.
IV (5-10 mg over 5 minutes) reduce short term
mortality in MI and lowers incidence of arrhythmias.
59. Esmolol
Cardioselective
Ultra short acting - t½ - 8 minutes.
Used IV.
Safer in critically ill patients and in emergencies.
Metoprolol
Cardioselective
Well-absorbed but undergoes first pass metabolism
Given twice daily
Dose: 50-200 mg
Used in hypertension and angina pectoris.
60. Acebutolol
Cardioselective
Used in hypertension and arrhythmias.
Celiprolol
β1 blocker and β2 agonist
Safer in asthmatics
Used in hypertension.
61. Propranolol
Nonselective
Dose: oral 10 mg BD to 160 mgTID.
First line drugs in mild to moderate hypertension
Used in HTN, angina, arrhythmias, migraine
63. Potassium-channel openers are drugs that
activate (open) ATP-sensitive K+ channels in
vascular smooth muscle and results vascular
smooth muscle relaxation.
64. Potassium channel openers
Open ATP-sensitive K+ channels in vascular
smooth muscle
Enhance K+ efflux
Membrane Hyperpolarization
↓ Ca 2+ entry
Reduced intracellular calcium
Smooth muscle relaxation
66. Nicorandil is an arterial and venous dilator.
MOA
Nicorandil
Open ATP-sensitive Act as nitric oxide
K+ channels donor
Enhance K+ efflux
Membrane Hyperpolarization
↓ Ca 2+ entry
Reduced intracellular calcium
Smooth muscle relaxation
Decrease preload and afterload, increase coronary blood flow
67. Use
Resistant angina
In combination with other drugs
Dose: 10-20 mg twice daily.
Adverse effects
Headache
Flushing
Palpitation
Dizziness
Hypotension
68. Similar to nicorandil.
Uses
Angina
Hypertension
70. Coronary vasodilator
But it is not used in angina as it diverts blood
from ischemic zone to non ischemic zone.
It inhibits platelet aggregation for which
it is used in post-MI and post-stroke patients
tor prevention of coronary and cerebral
thrombosis.
Dose 25-100 mgTID.
71. Long-term administration of low dose
aspirin is recommended to prevent myocardial
infarction.
Inhibits platelet aggregation.
Dose: 75-100mg
72. Anti-anginal action through inhibition of fatty
acid metabolism, also known as fatty acid
oxidation inhibitor.
Used in post MI patients.
Dose: 20 mgTID.
73. Recently introduced trimetazidine congener.
MOA
Prevents calcium overload in the myocardium during
ischemia and reduces myocardial O2 demand.
Uses
Prevention of angina as add on therapy.
Dose : 500 mg sustained release tablets twice daily.
Adverse effects
Weakness
Postural hypotension
Dizziness
Headache
Constipation
74. Nitrates + β blockers
Nifedipine + β blockers
Nitrates + CCB
Nitrates + β blockers+ CCB
If not controlled by 2 drug combination.