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Angiotensin II Receptor Blockers (ARBs)
Description
This group of medicines is known as Angiotensin II Receptor Blockers,
or ARBs. ARBs are used in the treatment of high blood pressure (hypertension).
These agents work by blocking the actions of angiotensin II (a substance
produced by the body to constrict blood vessels and raise blood
pressure). Blocking the action of angiotensin II lowers blood pressure.
These agents may also be used for other conditions as determined
by your doctor.
Brand Names:
Cozaar® (Losartan)
Diovan® (Valsartan)
Avapro® (Irbesartan)
Atacand® (Candesartan)
Micardis® (Telmisartan)
Teveten® (Eprosartan)
Benicar® (Olmesartan)
ARBs are available only with your doctor's prescription, in the
following dosage forms:
Candesartan:
Tablets
Eprosartan:
Tablets
Irbesartan:
Tablets
Losartan:
Tablets
Olmesartan:
Tablets
Telmisartan:
Tablets
Valsartan:
Tablets
Before Using This Medicine
In deciding to use a medicine, the risks of taking the medicine
must be weighed against the good it will do. This is a decision
you and your doctor will make. For the ARBs, the following should
be considered:
Allergies -- Tell your doctor if you have ever
had any unusual or allergic reaction to the alpha-blocker medicine
prescribed. Also tell your health care professional if you are allergic
to any other substances, such as foods, preservatives, or dyes.
Pregnancy -- Before taking any of these medicines,
make sure your doctor knows if you are pregnant or if you may become
pregnant. Most drugs in this class are contraindicated during pregnancy,
especially in the second and third trimesters
Breast-feeding -- Candesartan, eprosartan, and
telmisartan have been shown to enter breast milk, use caution. It
is not known whether losartan, irbesartan, olmesartan, and valsartan
passes into breast milk; use is contraindicated/not recommended.
Older adults -- Some side effects are more likely
to occur in the elderly, who are usually more sensitive to the effects
of alpha-blockers.
Other medicines -- Although certain medicines
should not be used together at all, in other cases two different
medicines may be used together even if an interaction might occur.
In these cases, your doctor may want to change the dose, or other
precautions may be necessary. When you are taking or receiving an
ARB, it is especially important that your health care professional
know if you are taking any of the following:
- Lithium
- NSAIDs
- Potassium-sparing diuretics (amiloride, spirinolactone,
potassium, triamterene)
- Potassium supplements
- High dose trimethoprim
Other medical problems -- The presence of other
medical problems may affect the use of the ARBs. Make sure you tell
your doctor if you have any other medical problems, especially:
- Kidney disease
- Liver disease
- Significant aortic/mitral stenosis
- Volume depletion (correct before initiating
ARB therapy)
Proper Use of This Medicine
To help you remember to take your medicine, try to get into the
habit of taking it at the same time each day.
For patients taking this medicine for high blood pressure
:
- In addition to the use of the medicine your
doctor has prescribed, treatment for your high blood pressure
may include weight control and care in the types of foods you
eat, especially foods high in sodium. Your doctor will tell you
which of these are most important for you. You should check with
your doctor before changing your diet.
- Many patients who have high blood pressure will
not notice any signs of the problem. In fact, many may feel normal.
However, if high blood pressure is not treated, it can cause serious
problems such as heart failure, blood vessel disease, stroke,
or kidney disease.
- Remember that this medicine will not cure your
high blood pressure but it does help control it. It is very important
that you take your medicine exactly as directed, even
if you feel well. You must continue to take it as directed if
you expect to lower your blood pressure and keep it down. You
may have to take high blood pressure medicine for the rest of
your life. Also, it is very important to keep your appointments
with your doctor, even if you feel well.
Dosing --
For candesartan:
Adults:
Hypertension:
Usual dose is 4-32 mg once daily; dosage must be individualized.
Blood pressure response is dose-related over the range of 2-32
mg. The usual recommended starting dose of 16 mg once daily
when it is used as monotherapy in patients who are not volume
depleted. It can be administered once or twice daily with total
daily doses ranging from 8-32 mg. Larger doses do not appear
to have a greater effect and there is relatively little experience
with such doses.
Congestive heat failure (unlabeled use):
Target dose: 32 mg
For eprosartan:
Adults:
Dosage must be individualized; can administer once or twice
daily with total daily doses of 400-800 mg. Usual starting dose
is 600 mg once daily as monotherapy in patients who are euvolemic.
Limited clinical experience with doses >800 mg.
For irbesartan:
Hypertension:
Children:
<6 years: Safety and efficacy have not been established.
6-12 years: Initial: 75 mg once daily; may be titrated to
a maximum of 150 mg once daily
Children 13 years and Adults: 150 mg once daily; patients may
be titrated to 300 mg once daily
Note: Starting dose in volume-depleted patients
should be 75 mg
Nephropathy in patients with type 2 diabetes and hypertension:
Adults: Target dose: 300 mg once daily
For losartan:
Adults:
Hypertension: The usual starting dose is 50 mg once daily.
Can be administered once or twice daily with total daily doses
ranging from 25-100 mg.
Usual initial doses in patients receiving diuretics or those
with intravascular volume depletion: 25 mg
Nephropathy in patients with type 2 diabetes and hypertension:
Initial: 50 mg once daily; can be increased to 100 mg once daily
based on blood pressure response
Stroke reduction (HTN with LVH): 50 mg once daily (maximum
daily dose: 100 mg); may be used in combination with a thiazide
diuretic
For olmesartan:
Adults:
Initial: Usual starting dose is 20 mg once daily; if initial
response is inadequate, may be increased to 40 mg once daily
after 2 weeks. May administer with other antihypertensive agents
if blood pressure inadequately controlled with olmesartan. Consider
lower starting dose in patients with possible depletion of intravascular
volume (eg, patients receiving diuretics).
For telmisartan:
Adults:
Initial: 40 mg once daily; usual maintenance dose range: 20-80
mg/day. Patients with volume depletion should be initiated on
the lower dosage with close supervision.
For valsartan:
Adults:
Hypertension: Initial: 80 mg or 160 mg once daily (in patients
who are not volume depleted); majority of effect within 2 weeks,
maximal effects in 4-6 weeks; dose may be increased to achieve
desired effect; maximum recommended dose: 320 mg/day
Heart failure: Initial: 40 mg twice daily; titrate dose to
80-160 mg twice daily, as tolerated; maximum daily dose: 320
mg. Note: Do not use with ACE inhibitors and
beta blockers.
Storage --
To store this medicine:
- Keep out of the reach of children.
- Store away from heat and direct light.
- Do not store in the bathroom, near the kitchen
sink, or in other damp places. Heat or moisture may cause the
medicine to break down.
- Do not keep outdated medicine or medicine no
longer needed. Be sure that any discarded medicine is out of the
reach of children.
Precautions While Using This Medicine
It is important that your doctor check your progress at regular
visits. This is to make sure the medicine is working for you and
to allow the dosage to be changed if needed.
Do not stop taking this medicine without first checking with
your doctor. Your doctor may want you to reduce gradually the
amount you are taking before stopping completely. Some conditions
may become worse when the medicine is stopped suddenly, and the
danger of heart attack is increased in some patients.
Make sure that you have enough medicine on hand to last through
weekends, holidays, or vacations. You may want to carry an extra
written prescription in your billfold or purse in case of an emergency.
You can then have it filled if you run out of medicine while you
are away from home.
Your doctor may want you to carry medical identification stating
that you are taking this medicine.
Before having any kind of surgery (including dental surgery)
or emergency treatment, tell the medical doctor or dentist in charge
that you are taking this medicine.
This medicine may cause some people to become dizzy, drowsy, or
lightheaded. Make sure you know how you react to this medicine
before you drive, use machines, or do anything else that could be
dangerous if you are dizzy or are not alert. If the problem
continues or gets worse, check with your doctor.
Before you have any medical tests, tell the doctor in charge that
you are taking this medicine. The results of some tests may be affected
by this medicine.
For patients taking this medicine for high blood pressure :
- Do not take other medicines unless they
have been discussed with your doctor.
This especially includes over-the-counter (nonprescription) medicines
for appetite control, asthma, colds, cough, hay fever, or sinus
problems since they may tend to increase your blood pressure.
Side Effects of This Medicine
Along with its needed effects, a medicine may cause some unwanted
effects. Although not all of these side effects may occur, if they
do occur they may need medical attention.
Check with your doctor as soon as possible if any of the following
side effects occur:
- Chest pain or palpitations
- Unrelenting headache
- Swelling of extremities, face, or tongue
- Muscle weakness or pain
- Respiratory difficulty or unusual cough
- Flu-like symptoms
- Persistent adverse reactions
- Signs and symptoms of overdose (in the order
in which they may occur)
- Hypotension, drowsiness, and shock
Other side effects may occur that usually do not need medical
attention. These side effects may go away during treatment as your
body adjusts to the medicine. However, check with your doctor if
any of the following side effects continue or are bothersome:
- Dizziness, fainting, or lightheadedness
- Postural hypotension
- Diarrhea
- Decreased libido (will resolve)
Although not all of the side effects listed above have been reported
for all of these medicines, they have been reported for at least
one of them. Since all of the ARBs are very similar, any of the
above side effects may occur with any of these medicines. However,
they may be more or less common with some agents than with others.
- After you have been taking an ARB for a while,
it may cause unpleasant or even harmful effects if you stop taking
it too suddenly.
Other side effects not listed above may also occur in some patients.
If you notice any other effects, check with your doctor.
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