Health Guide
Drug Guide

Antidepressant, monoamine oxidase (MAO) inhibitor (Oral route)

Brand Names:

Dosage Forms:

Uses of This Medicine:

Monoamine oxidase (MAO) inhibitors are used to relieve certain types of mental depression. They work by blocking the action of a chemical substance known as monoamine oxidase (MAO) in the nervous system.

Although these medicines are very effective for certain patients, they may also cause some unwanted reactions if not taken in the right way. It is very important to avoid certain foods, beverages, and medicines while you are being treated with an MAO inhibitor. Your health care professional will help you obtain a list to carry in your wallet or purse as a reminder of which products you should avoid.

These medicines are available only with your doctor's prescription.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, phenelzine and tranylcypromine are used in certain patients with the following medical conditions:

Dangerous reactions such as sudden high blood pressure may result when MAO inhibitors are taken with certain foods or drinks. The following foods should be avoided:

Before Using This Medicine:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to medicines in this group or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Children

Antidepressants must be used with caution in children, teenagers, and young adults with depression. Studies have shown occurrences of children, teenagers, and young adults thinking about suicide or attempting suicide in clinical trials for this medicine. More study is needed to be sure antidepressants are safe and effective in children, teenagers, and young adults .

Animal studies have shown that these medicines may slow growth in the young. Therefore, be sure to discuss with your doctor the use of these medicines in children.

Older adults

Dizziness or lightheadedness may be especially likely to occur in elderly patients, who are usually more sensitive than younger adults to these effects of MAO inhibitors.

Pregnancy

A limited study in pregnant women showed an increased risk of birth defects when these medicines were taken during the first 3 months of pregnancy. In animal studies, MAO inhibitors caused a slowing of growth and increased excitability in the newborn when very large doses were given to the mother during pregnancy.

Breast-feeding

Tranylcypromine passes into the breast milk; it is not known whether isocarboxazid or phenelzine passes into breast milk. Problems in nursing babies have not been reported.

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 any of these medicines, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using medicines in this class with any of the following medicines is not recommended. Your doctor may decide not to treat you with a medication in this class or change some of the other medicines you take.

Using medicines in this class with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Other interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Using medicines in this class with any of the following is not recommended. Your doctor may decide not to treat you with a medication in this class, change some of the other medicines you take, or give you special instructions about the use of food, alcohol, or tobacco.

Using medicines in this class with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use your medicine, or give you special instructions about the use of food, alcohol, or tobacco.

Other medical problems

The presence of other medical problems may affect the use of medicines in this class. Make sure you tell your doctor if you have any other medical problems, especially:

Proper Use of This Medicine:

Sometimes this medicine must be taken for several weeks before you begin to feel better. Your doctor should check your progress at regular visits, especially during the first few months of treatment, to make sure that this medicine is working properly and to check for unwanted effects.

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

MAO inhibitors may be taken with or without food or on a full or empty stomach. However, if your doctor tells you to take the medicine a certain way, take it exactly as directed.

Dosing

The dose medicines in this class will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of these medicines. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Missed dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

If you miss a dose of this medicine, take it as soon as possible. However, if it is within 2 hours of your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Keep out of the reach of children.

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions While Using This Medicine:

When taken with certain foods, drinks, or other medicines, MAO inhibitors can cause very dangerous reactions such as sudden high blood pressure (also called hypertensive crisis). To avoid such reactions, obey the following rules of caution:

This medicine will add to the effects of alcohol and other CNS depressants (medicines that slow down the nervous system, possibly causing drowsiness). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicine for seizures; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using this medicine.

Check with your doctor or hospital emergency room immediately if severe headache, stiff neck, chest pains, fast heartbeat, or nausea and vomiting occur while you are taking this medicine. These may be symptoms of a serious side effect that should have a doctor's attention.

Do not stop taking this medicine without first checking with your doctor. Your doctor may want you to reduce gradually the amount you are using before stopping completely.

Dizziness, lightheadedness, or fainting may occur, especially when you get up from a lying or sitting position. Getting up slowly may help. When you get up from lying down, sit on the edge of the bed with your feet dangling for 1 or 2 minutes. Then stand up slowly. If the problem continues or gets worse, check with your doctor.

This medicine may cause blurred vision or make some people drowsy or less alert than they are normally. 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 unable to see well or are not alert.

Antidepressants may cause some people to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. If you or your caregiver notice any of these adverse effects, tell your doctor right away.

Before having any kind of surgery, dental treatment, or emergency treatment, tell the medical doctor or dentist in charge that you are using this medicine or have used it within the past 2 weeks. Taking MAO inhibitors together with medicines that are used during surgery or dental or emergency treatments may increase the risk of serious side effects.

Your doctor may want you to carry an identification card stating that you are using this medicine.

For patients with angina (chest pain):

For diabetic patients:

After you stop using this medicine, you must continue to obey the rules of caution for at least 2 weeks concerning food, drink, and other medicine, since these things may continue to react with MAO inhibitors.

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.

Stop taking this medicine and get emergency help immediately if any of the following effects occur:

Symptoms of unusually high blood pressure (hypertensive crisis)
Chest pain (severe)
enlarged pupils
fast or slow heartbeat
headache (severe)
increased sensitivity of eyes to light
increased sweating (possibly with fever or cold, clammy skin)
nausea and vomiting
stiff or sore neck

Check with your doctor as soon as possible if any of the following side effects occur:

More common
Dizziness or lightheadedness (severe), especially when getting up from a lying or sitting position
Less common
Diarrhea
fast or pounding heartbeat
swelling of feet or lower legs
unusual excitement or nervousness
Rare
Dark urine
fever
skin rash
slurred speech
sore throat
staggering walk
yellow eyes or skin
Symptoms of overdose
Anxiety (severe)
confusion
convulsions (seizures)
cool, clammy skin
dizziness (severe)
drowsiness (severe)
fast and irregular pulse
fever
hallucinations (seeing, hearing, or feeling things that are not there)
headache (severe)
high or low blood pressure
muscle stiffness
sweating
trouble in sleeping (severe)
troubled breathing
unusual irritability

Some 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. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
Blurred vision
decreased amount of urine
decreased sexual ability
dizziness or lightheadedness (mild), especially when getting up from a lying or sitting position
drowsiness
headache (mild)
increased appetite (especially for sweets) or weight gain
increased sweating
muscle twitching during sleep
nausea
restlessness
shakiness or trembling
tiredness and weakness
trouble in sleeping
Less common or rare
Chills
constipation
decreased appetite
dryness of mouth

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.


Last Updated: 6/12/2013

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