Monoamine Oxidase Inhibitors Health Article

Definition

Monoamine oxidase inhibitors (MAO inhibitors) are medicines that relieve certain types of mental depression.

Purpose

MAO inhibitors are a type of antidepressant and are used to treat mental depression. Like other antidepressant drugs, MAO inhibitors help reduce the extreme sadness, hopelessness, and lack of interest in life that are typical in people with depression. MAO inhibitors are especially useful in treating people whose depression is combined with other problems such as anxiety, panic attacks, phobias, or the desire to sleep too much.

Description

Discovered in the 1950s, MAO inhibitors work by correcting chemical imbalances in the brain. Normally, natural chemicals called neurotransmitters carry signals from one brain cell to another. Some neurotransmitters, such as serotonin and norepinephrine, play important roles in controlling mood. But other substances in the brain may interfere with mood control by breaking down these neurotransmitters. Researchers believe that MAO inhibitors work by blocking the chemicals that break down serotonin and norepinephrine. This gives the neurotransmitters more time to do their important work.

Because MAO inhibitors also affect other chemicals throughout the body, these drugs may produce many unwanted side effects. They can be especially dangerous when taken with certain foods, beverages and medicines. Anyone taking these drugs should ask his or her physician or pharmacist for a list of products to avoid.

MAO inhibitors are available only with a physician's prescription. They are sold in tablet form. Some commonly used MAO inhibitors are isocarboxazid (Marplan), phenelzine (Nardil), and tranylcypromine (Parnate).

Recommended dosage

The recommended dosage depends on the type of MAO inhibitor and the type of depression for which it is being taken. Dosages may be different for different patients. Check with the physician who prescribed the drug or the pharmacist who filled the prescription for the correct dosage.

Always take MAO inhibitors exactly as directed by your physician. Never take larger or more frequent doses, and do not take the drug for longer than directed. See the physician regularly while taking this medicine, especially in the first few months of treatment. The physician will check to make sure the medicine is working as it should and will note unwanted side effects. The physician may also need to adjust the dosage during this period.

Several weeks may be needed for the effects of this medicine to be felt. Be sure to keep taking it as directed, even if it does not seem to be helping.

Do not stop taking this medicine suddenly. Tapering the dose may be necessary to reduce the chance of withdrawal symptoms. If it is necessary to stop taking the drug, check with the physician who prescribed it for instructions on how to stop.

MAO inhibitors may be taken with or without food, on a full or empty stomach. Check package directions or ask the physician or pharmacist for instructions on how to take the medicine. Remember that some foods and beverages must be avoided during treatment with MAO inhibitors.

Precautions

The effects of this medicine may continue for two weeks or more after patients stop taking it. All precautions should be observed during this period, as well as throughout treatment with MAO inhibitors.

MAO inhibitors may cause serious and possibly life-threatening reactions, such as sudden high blood pressure, when taken with certain foods, beverages, or medicines. The dangerous reactions may not begin until several hours after consuming these items. Aged cheeses, red wines, smoked or pickled meats, chocolate, caffeinated beverages, and foods containing monosodium glutamate (MSG) are among the foods and drinks to be avoided. Be sure to get a complete list from the physician who prescribed the medicine or the pharmacist who filled the prescription.

Do not drink any alcoholic beverages or reduced-alcohol or alcohol-free beer or wine while taking this medicine.

Anyone who is taking MAO inhibitors should not use any other medicine unless it has been approved or prescribed by a physician who knows that they are taking MAO inhibitors. This includes nonprescription (overthe-counter) medicines such as sleep aids; medicines for colds, cough,hay fever, or asthma (including nose drops or sprays); medicines to increase alertness or keep from falling asleep; and appetite control products.

Because MAO inhibitors work on the central nervous system, they may add to the effects of alcohol and other drugs that slow down the central nervous system, such as antihistamines, cold medicine, allergy medicine, sleep aids, medicine for seizures, tranquilizers, some pain relievers, and muscle relaxants. Anyone taking MAO inhibitors should check with his or her physician before taking any of the above.

MAO inhibitors may interact with medicines used during surgery, dental procedures, or emergency treatment. These interactions could increase the chance of side effects. Anyone who is taking MAO inhibitors should be sure to tell the health care professional in charge before having any surgical or dental procedures or receiving emergency treatment.

Some people feel drowsy, dizzy, lightheaded, or less alert when using MAO inhibitors. The drugs may also cause blurred vision. For these reasons, anyone who takes these drugs should not drive, use machines or do anything else that might be dangerous until they have found out how the drugs affect them.

These medicines also make some people feel light-headed, dizzy, or faint when they get up after sitting or lying down. To lessen the problem, get up gradually and hold onto something for support if possible.

Older people may be especially sensitive to the effects of MAO inhibitors. This may increase the chance of side effects, such as dizziness or lightheadedness.