Diltiazem

How it works

     * 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