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Generic Name: Metoprolol
Brand Name(s):
Information updated: April 1, 2000
Overview
Lopressor and Toprol belong to the group of drugs known as beta blockers.
That means they work partly by blunting the action of adrenaline, the body's
natural fight-or-flight chemical.
People normally respond to stressful
situations with a rapid pulse, a pounding heart and an increase in blood
pressure. Lopressor or Toprol helps block such reactions.
This medicine
is normally prescribed for hypertension, chest pain caused by angina and
prevention of a second heart attack.
Although the FDA has not
specifically approved Lopressor or Toprol for other purposes, doctors have
prescribed them to treat irregular heart rhythms, tremor, aggressive behavior
and to prevent migraine headaches.
The dose will vary depending upon the
condition being treated.
Side Effects and Interactions
Lopressor or Toprol can cause a number of side
effects. These include slow heart rate, cold hands and feet, insomnia,
nightmares, blurred vision, sexual difficulties, nerve tingling, dizziness,
nausea, stomach ache, gas, diarrhea, indigestion, rash, arthritis and muscle
pain.
The medicine may also have a negative effect on cholesterol and
other blood fats, so a lipid test before treatment and periodically thereafter
would be prudent.
Lopressor or Toprol are a little more likely to affect
the nervous system than certain other drugs in this class.
Be alert for
the beta blocker blues. Symptoms of psychological depression, fatigue, decreased
concentration, memory loss and mood swings may come on slowly and insidiously.
Notify your physician promptly of any adverse reactions, especially
breathing difficulties, fluid retention in the legs or a night cough.
Never stop taking any beta blocker medication abruptly unless you are
under very close medical supervision. Angina or a heart attack could occur.
These drugs may also make treatment of diabetes and thyroid disorders
more complicated. Your physician will need to monitor such conditions
closely.
Lopressor or Toprol can interact with a number of other
medicines. Antacids containing aluminum or calcium can reduce absorption and
interfere with the effectiveness of Lopressor or Toprol, as can many arthritis
drugs and aspirin.
Cholesterol-lowering medications like Cholybar,
Questran or Colestid and penicillin-type antibiotics might have the same effect
on this beta blocker.
The ulcer medicines Tagamet and Zantac may
increase the effects of either Lopressor or Toprol, however.
Other blood
pressure medicines such as Apresoline or calcium channel blockers like Calan or
Procardia could interact with either Lopressor or Toprol so that the
blood-pressure lowering power of each drug is enhanced.
Minipress is
more likely to cause fainting problems when combined with Lopressor.
Be
aware that over-the-counter asthma medicines containing epinephrine, the blood
thinner Coumadin or ergotamine-containing migraine drugs like Cafergot could all
interact badly with this drug.
Check with your doctor and pharmacist
before taking any other drugs to make sure you are aware of the risks the
combination may carry.
Special Precautions
Some people must be very careful if they take beta blockers. Asthmatics and patients with other respiratory problems are especially vulnerable, as these drugs can make breathing more difficult.
Lopressor or Toprol is a little better than other beta blockers in this regard, but monitor your breathing carefully.
People with heart failure must also be extremely cautious if prescribed beta blockers because the medicine could lead to cardiac complications.
Taking the Medicine
Lopressor or Toprol can be taken on an empty stomach, though they are best absorbed when
swallowed at meal time. Food may also reduce the risk of digestive tract upset.
To maintain
a constant level of the medicine in your blood stream try to maintain a regular regimen, taking the
drug at roughly the same times each day.
Joe Graedon is a pharmacologist. Teresa Graedon holds a doctorate in medical anthropology and is a nutrition expert. Their syndicated radio show can be heard on public radio.
© 2000