Monoamine Oxidase Inhibitors Information - Drug Interactions, Uses and Benefits

Type of Drug:

Antidepressants; mood-elevating agents; MAOls.

How the Drug Works:

Monoamine oxidase inhibitors (MAOls) prevent the breakdown of the body’s own mood-elevating substances. The effect may take several weeks to be noticed.

Uses:

To treat chronic (long-term) depression in patients who have not responded satisfactorily to other antidepressants. They are rarely used as first-line antidepressant therapy.

Unlabeled Uses: Occasionally doctors may prescribe MAOls for bulimia and panic disorder associated with agoraphobia (fear of open or public places) and glob us hystericus syndrome (choking sensation associated with hysteria). Phenelzine has been investigated for use as an aid in treating cocaine addiction, night terrors, post-traumatic stress disorder, and migraines resistant to other therapies. Tranylcypromine has been used to treat Binswanger’s encephalopathy, seasonal affective disorder, and subjective symptoms of multiple sclerosis.

Drug abuse and dependence: Drug abuse and dependence have been reported in patients using excessive doses of tranylcypromine and isocarboxazid. Some of these patients had a history of substance abuse. The following withdrawal symptoms have been reported: Restless­ness; anxiety; depression; confusion; hallucinations; headaches; weakness; diarrhea.

Hypertensive Crisis: Hypertensive crisis (extreme elevations in blood pressure) can result from coadministraton of MAOls and certain drugs and foods.

Chest pain: MAOls may suppress chest pain that would otherwise serve as a warning of myocardial ischemia (inadequate circulation of blood to the heart, usually as a result of heart disease).

Liver Dysfunction: Discontinue isocarboxazid use at first sign of liver dysfunction or jaundice (yellowing of skin or eyes).

Depression: Tranylcypromine and isocarboxazid may aggravate coexisting symptoms in depression, such as anxiety and agitation.

Tyramine-containing foods: Do not eat foods with high tyramine, dopamine, or tryptophan content (see the following listing) during or for 2 weeks after the discontinuation of MAOI’s. Any high-protein food that is aged or undergoes breakdown by a putrefaction process to improve flavor is suspected of producing a significant increase in blood pressure in patients taking MAOI’s. Do not take any new prescription medication without first reviewing it with your doctor or pharmacist. Do not drink alcoholic beverages or self-medicate with dietary supplements, cold, hay fever, or weight-reducing preparations while undergoing therapy. Do not consume excessive amounts of caffeine in any form, and report headache or other unusual symptoms promptly.

Other Problem Foods: Broad beans (fava beans, overripe); chocolate; caffeine (eg, coffee, tea, colas); ginseng.

Pregnancy: Safety for use during pregnancy has not been established. Use during pregnancy or in women of childbearing age only when clearly needed and when the potential benefits outweigh the potential hazards to the fetus.

Breastfeeding: Tranylcypromine appears in breast milk. It is not known if the other MAOls appear in breast milk. Because of the potential for serious adverse effects in the nursing infant, decide whether to discontinue nursing or the drug, taking into account the importance of the drug to the mother. Consult your doctor before you begin breastfeeding.

Children: Use in children younger than 16 years of age is not recommended.

Elderly: The most serious reactions to MAOI use involve changes in blood pressure. Older patients may suffer more problems than younger patients during and following an episode of increased blood pressure or malignant hyperthermia (extremely high fever). Older patients have less compensatory reserve to cope with any serious adverse reactions. Use with caution in the elderly.

Lab Tests: Lab tests may be required to monitor therapy. Tests may include periodic liver chemistry (isocarboxazid).

Drug Interactions:

Tell your doctor or pharmacist if you are taking or if you are planning to take any over-the-counter or prescription medications or dietary supplements with MAOI’s. Doses of one or both drugs may need to be modified or a different drug may need to be prescribed. The following drugs and drug classes interact with MAOls:

• anesthetic agents (eg, anesthesia, cocaine)
• anorexiants (eg, amphetamine, phentermine)
• antidiabetic agents (eg, insulin, sulfonylureas, glyburide, tolbutamide)
• beta blockers (eg, metoprolol, nadolol)
• buproprion HCI (eg, Zyban)
• meperidine (eg, Demerol)

Side Effects:

Every drug is capable of producing side effects. Many MAOI users experience no, or minor, side effects. The frequency and severity of side effects depend on many factors including dose, duration of therapy, and individual susceptibility. Possible side effects include:

Digestive Tract: Nausea; constipation; diarrhea; stomach pain; appetite loss.

Nervous System: Hyperactivity; tremor; muscle twitching; unusual muscle movements; headache; dizziness; faintness; anxiety; jitteriness; memory impairment; sleep disturbances (eg, sleeplessness, excessively long sleeping periods); weakness; fatigue; drowsiness; restlessness; agitation; exaggerated reflexes; mania (eg, irritability, euphoria, distractability, excitability); abnormal skin sensations; lethargy; sedation.

Circulatory System: Changes in heart rate and rhythm; postural and orthostatic hypotension (dizziness or light headedness when rising from a seated or lying position); palpitations (pounding in the chest).

Skin: Rash; itching; sweating; jaundice (yellowing of skin or eyes).

Other: Dilated (widened) pupils; stiff neck; dry mouth; urinary frequoncy; edem (fluid retention) blurred vision; weight g8in; sexual problem; chills; impotence; abnormal blood cell counts; glucome; heavy feeling.

Guidelines for Use:

• Phenelzine - Recommended initial dosage is 15 mg 3 times daily. Increase dose to at least 60 mg/day at a fairly rapid pace consistent with patient tolerance. It may be necessary to increase dose up to 90 mg/day to obtain sufficient MAO inhibition. Many patients do not show clinical response until treatment at 60 mg has been continued for 4 weeks or more. After maximum benefit is achieved, reduce dose slowly over several weeks. Maintenance dosage may be as low as 15 mg/day or 15 mg every other day; continued for as long as required.
• Tranylcypromine - The usual effective dose is 30 mg/day in divided doses. Improvement should be seen within 48 hours to 3 weeks after starting therapy. If there is no improvement after 2 weeks, increase dose in 10 mg/day increments at 1- to 3-week intervals. Dosage range may be extended to a maximum of 60 mg/day from the usual 30 mg/day. Gradually withdraw tranylcypromine when discontinuing therapy.
• Isocarboxazid - Recommended initial dosage is 10 mg twice daily. If tolerated, increase by 10 mg every 2 to 4 days to achieve a dose of 40 mg by the end of the first week of treatment. Dose can then be increased by increments of up to 20 mg/week, if needed and tolerated, to a maximum recommended dose of 60 mg/day. Daily dose should be divided into 2 to 4 doses. After a maximum clinical response is achieved, attempt to reduce the dose slowly over a period of several weeks with­out jeopardizing therapeutic response. Beneficial effect may not be seen in some patients for 3 to 6 weeks. If no response is obtained by then, discontinue therapy. Caution is indicated in patients for whom a dose of 40 mg/day is exceeded.
• Do not discontinue this medication or adjust dosage except on the advice of your doctor. Consult your doctor before taking any other medication, including nonprescription items, while taking an MAOI.
• This medicine may take several weeks to become effective. Continue to take as directed.
• If a dose is missed, take it as soon as possible. If several hours have passed or if it is nearing time for the next dose, do not double the dose in order to catch up, unless advised to do so by your doctor. If more than one dose is missed, or it is necessary to establish a new dosage schedule, contact your doctor.
• Avoid tyramine-containing foods, alcohol, caffeine, and tryptophan (see Precautions).
• May cause drowsiness or blurred vision. Use caution while driving or performing other tasks requiring alertness, coordination, or physical dexterity.
• Dizziness, weakness, or fainting may occur when rising from a lying or sitting position. If this occurs, get up slowly.
• At doses over 30 mg/day, postural hypotension (dizziness or lightheadedness when rising from a seated or lying position) is a major side effect and may result in fainting. Dosage increases will be more gradual in patients showing a tendency toward low blood pressure at the beginning of therapy. Postural hypotension may be relieved by lying down until blood pressure returns to normal.
• Hypertensive crises (increase in blood pressure) as a result of concur­rent use of MAOI and certain foods or drugs (see Precautions) can occur and are potentially fatal. These crises usually occur within several hours after ingestion of the interacting food or drug. Notify your doctor immediately if you experience a headache that starts in the back of the head and moves forward, pounding in the chest, neck stiffness or soreness, nausea, vomiting, sweating (sometimes with fever or cold, clammy skin), dilated pupils, sensitivity to light, or changes in heart rate with or without chest pain or tightness.
• Notify your doctor if you experience rash or intolerable side effects.
• Use may complicate other medical treatment (eg, general anesthesia, surgery). Inform your doctors and dentist about your use of MAOls. Wear a Medic Alert bracelet or carry a card saying that you are taking an MAOI.
• A waiting period of 10 to 14 days is recommended when switching from one MAOI to another or from a dibenzapine-related agent. Other medications that interact with MAOls (eg, fluoxetine) have different waiting periods. Discuss appropriate waiting periods for changes in therapy with your doctor or pharmacist.
• Blood pressure will need to be monitored frequently.
• Lab tests may be required to monitor therapy. Be sure to keep appointments.
• Store at room temperature.

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