Last Updated June 2005
What are calcium channel blockers
(CCBs) and how do they work? CCBs are oral medications which relax
the muscles around blood vessels allowing for better blood flow
through the blood vessels. They also have effects on the electrical
system of the heart and can be useful in slowing or regulating
fast heart rates. They are often used in the treatment of systemic
hypertension. Although no randomized clinical trials have been
performed in patients with PAH, CCBs have been used to treat PAH
for over 25 years.
How are CCBs given?
CCBs are pills which are taken by mouth. Depending on the specific
medication and the dose, they may be taken from one to three times
a day. Some CCBs come in intravenous form as well and are used
in hospitalized patients to control heart rate and blood pressure.
The CCBs used most frequently in patients with PAH are nifedipine,
diltiazem or amlodopine. While early studies supported more widespread
use of CCBs for treatment of PAH, it now appears that they are
beneficial in only a small subset of PAH patients (less than 10%).
The subset of patients with PAH who may benefit from CCBs are
those who have undergone vasodilator testing during right heart
catheterization and have demonstrated a very good response.
What are the major problems with calcium channel blockers?
Early recommendations once favored relatively high doses of CCBs
in patients with PAH but many experts now agree that these medicines
should be introduced more cautiously and the dose increased only
as tolerated. Patients with PAH with severe right heart failure
should not use CCBs. Verapamil, a CCB which can depress heart
function, should not be used in patients with PAH. Patients with
PAH receiving CCBs should be monitored closely to determine the
safety and efficacy of the therapy. Side effects can include dizziness,
low blood pressure, and fluid retention.
How do patients obtain calcium channel blockers?
CCBs must be prescribed by a physician and can be obtained at
any pharmacy. All insurance pays for CCBs.
What is digoxin and how does it work?
Digoxin is a drug which may assist the pumping of the heart. Digoxin
also modulates the electrical activity in the heart. The use of
digoxin in PAH has not been very well studied but it is sometimes
used to help manage heart failure and/or control irregular heart
beats.
How is digoxin given?
Digoxin is a pill which is taken by mouth once a day.
What are the major problems with digoxin?
Digoxin has a very narrow therapeutic range. It can cause irregular
heart rhythms, nausea and changes in vision, especially when levels
in the blood are increased. Digoxin can interact with other medications.
A blood test to determine levels of digoxin can help determine
the appropriate dose for each patient and help to avoid side effects.
How do patients obtain digoxin?
Digoxin must be prescribed by a physician and can be obtained
at any pharmacy. All insurance pays for digoxin.
What is warfarin and how does it work?
Warfarin is a drug that "thins" the blood and prevents it from
clotting normally. It has been shown that blood clots can occur
in some patients with PAH and may contribute to their disease.
Warfarin has not been well studied in PAH but uncontrolled studies
suggest that it may be helpful for patients with idiopathic PAH.
It is unknown whether this advantage (if any) outweighs the risk
of bleeding complications. Use of warfarin in other diseases associated
with the development of PAH has not been studied. Warfarin therapy
should be considered in PAH patients treated with intravenous
epoprostenol or intravenous treprostinil as it may help prevent
clots from forming in their catheters.
How is warfarin given?
Warfarin is a pill which is taken by mouth once a day.
What are the major problems with warfarin?
Warfarin can be associated with excessive bleeding since it prevents
blood from clotting normally. It interacts with many other medications,
and many foods can either increase or decrease its effect. Blood
tests to measure an INR (International Normalized Ratio) are required
to monitor the effect of warfarin on blood clotting. This is usually
obtained weekly when patients first begin warfarin therapy and
then monthly once they reach a stable dose. There is no consensus
as to what degree of anticoagulation is appropriate for patients
with PAH, but most experts target an INR of 1.5 to 2.5. Warfarin
can cause serious birth defects and should not be taken by women
who are pregnant or who may become pregnant.
How do patients obtain coumadin?
Warfarin must be prescribed by a physician and can be obtained
at any pharmacy. All insurance pays for warfarin.
What are diuretics and how do they work?
Diuretics are medicines which help treat heart failure and fluid
retention (from heart failure and/or side effect of CCB). They
work by stimulating the kidneys to increase urine output. There
are several different types of diuretics and they come in pill
and intravenous form.
How are diuretics given?
Diuretics are taken one to two times a day by mouth. Diuretics
are used in PAH patients with or without evidence of heart failure
(e.g. swelling in the legs, fluid in the abdomen). Diuretics,
along with careful attention to salt and fluid intake, help maintain
the proper amount of fluid in the circulation.
What are the major problems with diuretics?
Rapid or excessive use of diuretics can lead to dehydration, low
blood pressure, chemical imbalances in the blood, and problems
with kidney function. Blood tests to monitor chemistry and kidney
function should be obtained regularly in patients receiving diuretic
therapy.
How do patients obtain diuretics?
Diuretics must be prescribed by a physician and can be obtained
at any pharmacy. All insurance pays for diuretics.
What is oxygen and how does it work?
Oxygen is required for life and is a component of the air we breathe.
Low oxygen levels can cause pulmonary blood vessels to constrict
(narrow) and this may worsen PAH. It is best to maintain an oxygen
saturation of at least 90% or higher in patients with PAH when
and if possible. This can be achieved in most patients by supplemental
oxygen therapy.
How is oxygen given?
Supplemental oxygen is supplied in tanks which must be prepared
and delivered by an oxygen supply company. The oxygen is inhaled
by patients via a nasal cannula or a face mask which is attached
to the oxygen tank by plastic tubing. At home, patients use a
machine called a condenser which supplies oxygen indefinitely,
although it requires electricity to work. When patients are outside
of the home, oxygen is supplied by portable tanks that last for
a few hours only, depending upon how much oxygen is required.
The rate at which oxygen is set to flow varies from patient to
patient and is prescribed by a physician. Usual flow rates range
from 1-6 liters/min.
What are the major problems with oxygen therapy?
Depending on the flow rate, oxygen delivered via nasal cannula
can cause dryness in the nose which can lead to irritation and
occasionally nosebleeds. Humidification of the oxygen minimizes
this problem. While it can be bulky and may last only a few hours,
portable oxygen allows patients to use oxygen while going about
their normal activities outside of the home.
How do patients obtain oxygen therapy?
Oxygen therapy must be prescribed by a physician. Insurers generally
require that patients have a measurement of blood oxygen to qualify
them for therapy before they will provide it.
