close

Enter

Log in using OpenID

Antianginal Agents: Nitrates

embedDownload
Antianginal
Agents
Dr.Shadi-Sarahroodi
Pharm.D & PhD
Qom University of Medical sciences
Iran
PUBLISHED BY
www.medicalppt.blogspot.com
www.medicalppt.blogspot.com
for more lecture notes
Angina Pectoris (Chest Pain)

When the supply of oxygen and
nutrients in the blood is insufficient
to meet the demands of the heart,
the heart muscle aches.
www.medicalppt.blogspot.com
for more lecture notes
Types of Angina

Atherosclerotic angina

Vasospastic angina

Unstable angina
(also called classic or effort angina)
(also called Prinzmetal’s or variant angina)
(also called preinfarction or crescendo angina)
www.medicalppt.blogspot.com
for more lecture notes
Antianginal Agents:
Therapeutic Objectives


Increase blood flow to ischemic heart muscle
and/or
Decrease myocardial oxygen demand
www.medicalppt.blogspot.com
for more lecture notes
Antianginal Agents



Nitrates
Beta blockers
Calcium channel
blockers
www.medicalppt.blogspot.com
for more lecture notes



intracellular conversion to nitrite ions, and then
to nitric oxide
activates guanylate cyclase and increases the
cells' cyclic guanosine monophosphate (cGMP).
Elevated cGMP ultimately leads to
dephosphorylation of the myosin light chain,
resulting in vascular
smooth muscle relaxation
www.medicalppt.blogspot.com
for more lecture notes
Organic Nitrates
Ferid Murad
www.medicalppt.blogspot.com
for more lecture notes
Antianginal Agents:
Nitrates
Available forms:
Sublingual
Buccal
Chewable tablets
Capsules
Ointments
Transdermal patches
Inhalable sprays
Intravenous solutions
www.medicalppt.blogspot.com
for more lecture notes
BENEFITS OF NITRATES





Reduce myocardial oxygen demand by dilating veins and
increase venous pooling of blood
Increase systemic arteriolar vasodilation (intravenous
forms only)
Directly dilate undiseased coronary arteries, helping
restore blood flow deep within myocardial tissues
Decrease ventricular wall tension due to increased venous
pooling
Improve exercise tolerance
www.medicalppt.blogspot.com
for more lecture notes
Antianginal Agents:
Nitrates
Nitroglycerin




Prototypical nitrate
Large first-pass effect with PO forms
Used for symptomatic treatment of ischemic
heart conditions (angina)
IV form used for BP control in perioperative
hypertension, treatment of CHF, ischemic pain,
and pulmonary edema associated with acute MI
www.medicalppt.blogspot.com
for more lecture notes
Antianginal Agents:
Nitrates


isosorbide dinitrate
(Isordil, Sorbitrate, Dilatrate SR)
isosorbide mononitrate
(Imdur, Monoket, ISMO)
Used for:



Acute relief of angina
Prophylaxis in situations that may provoke angina
Long-term prophylaxis of angina
www.medicalppt.blogspot.com
for more lecture notes
www.medicalppt.blogspot.com
for more lecture notes
Antianginal Agents:
Nitrates
Side Effects

Headache
– Usually diminish in intensity and
frequency with continued use



Tachycardia, postural hypotension
Tolerance may develop
facial flushing, and tachycardia
www.medicalppt.blogspot.com
for more lecture notes
Tolerance




blood vessels become desensitized
to vasodilation
daily “nitrate-free interval”
typically 10 to 12 hours, usually at
night, because demand on the heart
is decreased at that time
variant angina worsens early in the morning,
perhaps due to circadian catecholamine surges
www.medicalppt.blogspot.com
for more lecture notes
Antianginal Agents: Beta
Blockers
www.medicalppt.blogspot.com
for more lecture notes
Antianginal Agents: Beta
Blockers
Mechanism of Action


Decrease the HR, resulting in decreased
myocardial oxygen demand and increased oxygen
delivery to the heart
Decrease myocardial contractility, helping to
conserve energy or decrease demand
www.medicalppt.blogspot.com
for more lecture notes


Propranolol is the prototype: not
cardioselective
metoprolol or atenolol, are
preferred
www.medicalppt.blogspot.com
for more lecture notes


All β-blockers are nonselective at
high doses and can inhibit β2
receptors.
Important in asthmatics.
www.medicalppt.blogspot.com
for more lecture notes
contraindication





Asthma
Diabetes
severe bradycardia
peripheral vascular disease
chronic obstructive pulmonary
disease.
www.medicalppt.blogspot.com
for more lecture notes


Do not discontinue β-blocker therapy
abruptly.
The dose should be gradually tapered
off over 5 to 10 days to avoid rebound
angina or hypertension.]
www.medicalppt.blogspot.com
for more lecture notes
Antianginal Agents:
Calcium Channel Blockers
www.medicalppt.blogspot.com
for more lecture notes
Mechanism of Action


Calcium influx is increased in
ischemia because of the membrane
depolarization that hypoxia
produces
In turn, this promotes the activity
of several adenosine triphosphate–
consuming enzymes, thereby
depleting energy stores and
worsening the ischemia
www.medicalppt.blogspot.com
for more lecture notes
Antianginal Agents:
Calcium Channel Blockers



Cause peripheral arterial vasodilation
Reduce myocardial contractility
(negative inotropic action)
Result: decreased myocardial oxygen demand
www.medicalppt.blogspot.com
for more lecture notes
Nifedipine






a dihydropyridine derivative
arteriolar vasodilator
Oral
Usually: extended-release tablets.
Hepatic metabolism
Eliminate in both urine and the feces
www.medicalppt.blogspot.com
for more lecture notes
Side Effects





Flushing
Headache
Hypotension
peripheral edema as
all calcium-channel blockers are with
constipation is a problem
www.medicalppt.blogspot.com
for more lecture notes
Verapamil



Slows AV conduction
decreases heart rate, contractility,
blood pressure, and oxygen demand
contraindicated in patients with
preexisting depressed cardiac function
or AV conduction abnormalities
www.medicalppt.blogspot.com
for more lecture notes
Diltiazem



slow AV conduction
decrease the rate of firing of the
sinus node pacemaker
metabolized by the liver
www.medicalppt.blogspot.com
for more lecture notes

PUBLISHED BY
 www.medicalppt.blogspot.com
www.medicalppt.blogspot.com
for more lecture notes
Author
Document
Category
Uncategorized
Views
32
File Size
649 KB
Tags
1/--pages
Report inappropriate content