* Diltiazem may be used for the treatment of high blood pressure or
angina.
* Experts believe that diltiazem works by inhibiting the movement of
calcium ions across cardiac (heart) muscle and the smooth muscle
lining blood vessel walls.
* This effect dilates (widens) blood vessels, reducing how hard the
heart has to work to pump blood around the body, which reduces
blood pressure. This in turn reduces the demand for oxygen by the
heart, which reduces symptoms of angina. Heart rate may also be
slightly reduced and the capacity for exercise is increased.
* Diltiazem belongs to the class of medicines known as calcium
channel blockers (may also be called a calcium channel antagonist).
Upsides
* May be used for the treatment of high blood pressure
(hypertension), alone or in combination with other agents for high
blood pressure.
* May be used as an ongoing treatment to relieve symptoms such as
chest pain in people with chronic stable angina, or angina due to
coronary artery spasm. Will not relieve acute episodes of angina
(other medications such as sublingual nitroglycerin are used for
this purpose).
* Available as a tablet, an extended-release (long-acting) tablet,
and an extended-release capsule.
* Can improve a person's tolerance to exercise and keep their blood
pressure at acceptable levels during exercise. Heart rate at
maximal exercise does not change or is slightly reduced.
* Does not weaken how hard the heart contracts (does not have a
negative inotropic effect).
* Lowers blood pressure in both the standing and the sitting
position. Does not tend to cause as much of a drop in blood
pressure as some other blood pressure lowering agents when going
from a lying down to standing position. Does not cause a reflex
tachycardia (a compensatory fast heart rate that often occurs when
blood pressure drops).
* Generic diltiazem is available.
Downsides
If you are between the ages of 18 and 60, take no other medication or
have no other medical conditions, side effects you are more likely to
experience include:
* Rhinitis, headache, sore throat, constipation, edema (fluid
retention), skin rashes (although these are usually transient), and
a lack of energy are the most commonly reported side effects.
* May slightly reduce resting heart rate. However, in some people, it
may cause an abnormally slow heart rate; those with preexisting
heart conditions are more at risk.
* May occasionally cause liver injury; however, this is usually
reversible on discontinuation.
* May not be suitable for people with certain preexisting heart
conditions, and in those with low blood pressure (less than 90 mmHg
systolic). Caution should be used when giving diltiazem to people
with kidney or liver disease, because not many studies have been
done in people with these conditions.
* May interact with a number of other drugs including cimetidine,
clonidine, digoxin, anesthetics, those that are metabolized by
certain hepatic enzymes such as CYP3A4, statins, and some other
drugs that also affect the heart (such as beta-blockers).
Notes: In general, seniors or children, people with certain medical
conditions (such as liver or kidney problems, heart disease, diabetes,
seizures) or people who take other medications are more at risk of
developing a wider range of side effects. For a complete list of all
side effects, [84]click here.
Bottom Line
Diltiazem may be used for the treatment of high blood pressure or
chronic stable angina. Rhinitis, headache and constipation are commonly
reported side effects.
Tips
* Extended-release diltizem capsules should be taken on an empty
stomach (this means one hour before food or two hours after food).
Most other diltiazem formulations can be taken either with or
without food; however, you should always check the instructions on
the label.
* Extended-release tablets and capsules should be swallowed whole. Do
not crush or chew.
* Take diltiazem around the same time every day. Follow the
directions on your prescription label carefully, and ask your
doctor or pharmacist to explain any part you do not understand.
Take exactly as directed. Do not take more or less of it or take it
more often than prescribed by your doctor.
* Although diltiazem may be used to prevent ongoing angina symptoms
such as chest pain, it does not relieve an acute attack of angina.
Most people are also prescribed a medication like sublingual
nitroglycerin for this purpose. Talk to your doctor if you do not
have a medication that you can take for sudden-onset chest pain.
* Sometime diltiazem may make you dizzy when you go from a sitting or
lying down position to a standing position; the risk is greater if
you also take other medications for high blood pressure. Stand up
slowly if this happens to you.
* See your doctor if you have a skin rash that persists or other side
effects that are affecting your quality of life.
Response and Effectiveness
* The time to peak concentrations varies depending on the formulation
used; it can take up to four to six hours for extended-release
tablets to reach their peak.
* Once absorbed, diltiazem is metabolized in the liver to an active
metabolite which is approximately 25 to 50% as potent at dilating
the coronary arteries as diltiazem.
* The peak blood pressure-reducing and blood vessel-widening effects
occur three to six hours after oral administration of diltiazem
extended-release capsules, and at least 50% of the effect is still
present after 24 hours.
* Immediate-release dilitazem tablets are usually taken three or four
times a day. Extended-release capsules or tablets are usually taken
one or two times a day.
References
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