GENERIC NAME: nitroglycerin
BRAND NAME: Nitro-Bid; Nitro-Dur; Nitrostat; Transderm-Nitro; Minitran; Deponit; Nitrol
DRUG CLASS AND MECHANISM: Nitroglycerin is a
vasodilator (a
medication that dilates blood vessels) that frequently is used
in the
management of angina pectoris. Synthesized in 1846,
nitroglycerin was
first used to treat anginal attacks in 1879. It was granted FDA
approval
in 1938.
Blood returning from the body in the veins must be pumped by
the heart
through the lungs and into the arteries against the high
pressure in the
arteries. In order to accomplish this work, the heart's muscle
must
produce and use energy ("fuel"). The production of
energy
requires oxygen. Angina pectoris (angina) or "heart
pain" is due
to an inadequate flow of blood (and oxygen) to the muscle of
the heart. It
is believed that all nitrates, including nitroglycerin, correct
the
imbalance between the flow of blood and oxygen to the heart and
the work
that the heart must do by dilating the arteries and veins in
the body.
Dilation of the veins reduces the amount of blood that returns
to the
heart that must be pumped . Dilation of the arteries lowers the
pressure
in the arteries against which the heart must pump. As a
consequence, the
heart works less and requires less blood and oxygen.
Additionally, in patients with angina, nitroglycerin
preferentially
dilates blood vessels that supply the areas of the heart where
there is
not enough oxygen, thereby delivering oxygen to the heart
tissue that
needs it most.
PRESCRIPTION: yes
GENERIC AVAILABLE: yes (for some dosage
forms)
PREPARATIONS: extended-release capsules containing
2.5, 6.5, 9,
or 13 mg; 2% ointment with tape for application; patches (or
transdermal
delivery systems) which deliver 0.1, 0.2, 0.3, 0.4, 0.6, or 0.8
mg of
nitroglycerin per hour; buccal tablets containing 1, 2, or 3 mg
of
nitroglycerin in an extended-release formulation; a
translingual spray
which delivers 0.4 mg of nitroglycerin per spray; sublingual
tablets
containing 0.15 or 0.3mg.
STORAGE: All formulations should be kept at room
temperature,
15-30°C (59-86°F). The sublingual tablets are
especially
susceptible to moisture. They should NOT be kept in
bathrooms
or kitchens
because of the higher degrees of moisture there. Care should be
taken to
replace the sublingual tablets every six months.
PRESCRIBED FOR: Nitroglycerin is indicated for the
acute
treatment and prevention of angina.
DOSING: For the treatment of acute angina attacks or
for acute
prevention (i.e. immediately before encountering situations
likely to
bring on an anginal attack): one tablet is allowed to dissolve
under the
tongue or in the buccal pouch (between the cheek and gums), or
one spray
is given of the lingual spray. (Nitroglycerin for sublingual or
buccal use
as well as spray are rapidly absorbed from the lining of the
mouth for
immediate effects.) This may be repeated every 5 minutes as
needed. If
angina is not relieved after a total of 3 doses, the patient
should be
taken to a hospital or a physician should be contacted. If
lingual spray
is used, the canister of spray should not be shaken prior to
use, and it
should be sprayed onto or under the tongue and then the mouth
closed.
For prevention of angina, ointment may be applied using special
dose-measuring application papers provided with the ointment.
The
appropriate amount of ointment is squeezed as a thin layer onto
the paper,
and the paper is used to spread the ointment onto nonhairy area
of skin.
The ointment should not be allowed to come into contact with
the hands so
that there is no absorption from the hands. Transdermal patches
also are
used for prevention. Patches may be applied to any hairless
site but
should not be applied to areas with cuts or calluses. Firm
pressure should
be used over the patch to ensure contact with the skin. The
patch should
not be cut or trimmed . Patches are waterproof and should not
be affected
by showering or bathing. Capsules of long-acting nitroglycerin
also are
used for prevention. They usually are prescribed 2 to 3 times
per day and
are taken 1 to 2 hours after a meal.
DRUG INTERACTIONS: Since nitroglycerin can cause
hypotension
(low blood pressure), other medications which also cause
hypotension may
produce an unwanted additive effect. Such drugs might include
medicines
used to treat high blood pressure, some antidepressants; some
anti-psychotics, quinidine, procainamide, benzodiazepines such
as diazepam
(Valium) or opiates (e.g. morphine). Since alcohol also may
intensify the
blood pressure lowering effect of nitroglycerin, patients
receiving
nitroglycerin should be advised to drink alcoholic beverages
with caution.
Ergot alkaloids (e.g. Cafergot) and Imitrex can oppose the
vasodilatory
actions of nitroglycerin and may precipitate angina. A similar
effect can
occur with ephedrine and the decongestants pseudoephedrine (Sudafed) and
propanolamine.
PREGNANCY: Since most persons who use nitroglycerin
are over 50
years of age, experience with the use of nitroglycerin during
pregnancy is
limited. Nitroglycerin can be used during pregnancy if in the
judgment of
the physician the potential benefits justify the potential
(though
unknown) risks to the fetus.
NURSING MOTHERS: It is not known if nitroglycerin is
secreted in breast milk.
SIDE EFFECTS: A persistent, throbbing headache
commonly occurs
with nitroglycerin therapy. Aspirin, acetaminophen, or
ibuprofen may be
used to relieve the pain. Flushing of the head and neck can
occur with
nitroglycerin therapy as can an increase in heart rate or
palpitations.
This can be associated with a drop in blood pressure which can
be
accompanied by dizziness or weakness. To reduce the risk of low
blood
pressure, patients often are told to sit or lie down during and
immediately after taking nitroglycerin.
Last Editorial Review: 12/31/1997
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