Isocarboxazid (Marplan): Uses, Food Limits and Warnings

What isocarboxazid is

Isocarboxazid is a tablet in the monoamine oxidase inhibitor (MAOI) group of antidepressants. It is sold as Marplan.

NIMH says older antidepressants such as MAOIs are associated with more side effects, though they can still suit some people. Hearing about an older medicine can feel like a last resort, but it is often just one more option to weigh with someone who knows your history.

What it is approved for, and off-label uses

The FDA label says isocarboxazid is indicated for the treatment of depression. It also says it is not a first-choice antidepressant for people newly diagnosed, and should be kept for those who have not responded well to other antidepressants, because of its serious side effects.

Its effectiveness was shown in 6-week trials in outpatients with major depression, many of whom also had anxious mood, panic or phobic symptoms. That is a description of the people studied, and it does not make anxiety an approved use. The label says long-term use beyond 6 weeks has not been systematically evaluated, and that people on it longer should be checked regularly. It has not been adequately studied in people in the hospital for depression. It is not approved for children or for bipolar depression.

MedlinePlus says only that it may be prescribed for other uses, without naming them, so this page does not list one.

How it is thought to work

The label describes isocarboxazid as a non-selective MAOI that blocks the enzyme in the brain, heart and liver. The way MAOIs act as antidepressants is not fully understood, but it is thought to involve raising levels of certain chemical messengers in the brain.

What taking it can be like

MedlinePlus says it may take 3 to 6 weeks or longer to feel the full benefit, and to tell your doctor if symptoms do not improve during the first 6 weeks. That can feel like a long wait, so regular check-ins are helpful.

Food planning becomes part of the routine. The label says to avoid cheese (especially strong or aged kinds), sour cream, Chianti wine, sherry, beer including non-alcoholic beer, liqueurs, pickled herring, anchovies, caviar, liver, canned figs, raisins, overripe bananas or avocados, chocolate, soy sauce, sauerkraut, fava bean pods, yeast extracts, yogurt, meat extracts, meat prepared with tenderizers, and dry sausage. It also says to avoid alcoholic drinks and excess caffeine in any form.

MedlinePlus says the medicine may remain in your body for 2 weeks after you finish it, so tell any provider who wants to give you something new during that time.

Side effects and warnings

Boxed warning: in short-term studies, antidepressants increased the risk of suicidal thoughts and behavior in children, teens and young adults. No increase appeared in adults over 24, and adults 65 and older had less risk. Anyone taking it should be observed closely, especially early on. In a crisis, call or text 988, or call 911. Locascio Wellness does not provide emergency services. Our crisis resources page lists more help.

The most important reaction is a hypertensive crisis, a sudden rise in blood pressure that has sometimes been fatal. Signs can include a headache spreading from the back of the head, pounding heartbeat, stiff or sore neck, nausea, vomiting, sweating, light sensitivity and chest tightness. Treat this as an emergency and call 911.

• Do not combine with: other MAOIs, tricyclics and related medicines, SSRIs, bupropion, buspirone, stimulants such as amphetamines, cold, hay fever or weight products with decongestants, dextromethorphan, meperidine and alcohol. The label also lists some blood pressure, diuretic, antihistamine, sedative and anesthetic medicines.
• The label says not to use it with known or suspected blood vessel problems in the brain, heart disease, high blood pressure, a history of headache, pheochromocytoma, a history of liver disease or abnormal liver tests, or severe kidney impairment.
• Low blood pressure and faintness can occur, and drowsiness may affect driving or using machinery.
• It can have varying effects on seizures, and the label calls for periodic liver tests.
• Tell your prescriber if you are pregnant, planning a pregnancy or breastfeeding.

Can it be managed online in Pennsylvania and New York

The label says Marplan is not a controlled substance, and it does not limit it to a certified healthcare setting. Still, it says blood pressure should be followed closely and liver tests should be done periodically. A video visit cannot do either directly, so ask how they would be arranged. An emergency reaction needs 911, not a video visit.

A licensed psychiatrist on our team, a Doctor of Osteopathic Medicine (DO) with more than three decades of practice, offers online depression treatment and medication management by secure video for people physically located in Pennsylvania or New York during each visit. Our therapists do not prescribe.

Whether it is an option for you is a decision for you and your prescriber. Ask us whether our psychiatrist can help using our medication contact form.