- What Is an MAOI?
- MAOI Side Effects
- MAOIs and Drug Interactions
- MAOI Diet
- MAOIs and Pregnancy
- Monoamine oxidase inhibitors
- What are Monoamine Oxidase Inhibitors used for?
- What are the differences between Monoamine Oxidase Inhibitors?
- Are Monoamine Oxidase Inhibitors safe?
- What are the side effects of Monoamine Oxidase Inhibitors?
- MAO inhibitors: Risks, benefits, and lore
- MAO inhibitors: the forgotten antidepressant that saved my life
- Giving SSRIs a try
- A case for MAOIs
- Elsevier Connect Contributor
- Monoamine oxidase inhibitors (MAOIs) for depression
- MAOIs available in Australia
- How do MAOIs work?
- Diet and MAOIs
- MAOIs and other medicines
- Taking MAOIs
- Side effects of MAOIs
- Who should not take MAOIs?
- Reversible inhibitors of monoamine oxidase (RIMAs)
- Switching antidepressant medicines
- Young people starting antidepressants
What Is an MAOI?
MAOIs were the first type of antidepressant developed, and became widely used in the 1950s.
A monoamine oxidase inhibitor, or MAOI, is a type of antidepressant drug.
In addition to treating depression, MAOIs are sometimes used to treat such conditions as:
- Bipolar disorder
- Panic disorder
- Social anxiety disorder
- Post-traumatic stress disorder (PTSD)
- Eating disorders, including anorexia or bulimia
- Other psychiatric disorders
- Parkinson’s disease
MAOIs balance the level of certain chemicals in the brain by inhibiting the enzyme known as monoamine oxidase.
The following medicines are examples of MAOIs:
- Isocarboxazid (Marplan)
- Phenelzine (Nardil)
- Selegiline (Emsam)
- Tranylcypromine (Parnate)
MAOIs were the first type of antidepressant developed, and became widely used in the 1950s.
Today, a doctor typically prescribes an MAOI only when other antidepressants fail, because newer drugs are often more effective and have fewer side effects.
MAOI Side Effects
There is a risk of serious side effects, especially when MAOIs are combined with certain food or drugs.
Some side effects of MAOIs include:
- Dry mouth
- Diarrhea or constipation
- Insomnia or other sleep disturbance
- Skin reactions
- Low blood pressure
- Involuntary muscle jerks or muscle aches
- Reduced sexual desire or decreased sexual ability
- Weight gain
- Difficulty urinating
- Tingling sensation of the skin
MAOIs — like all antidepressants — also carry a black-box warning about the potential for suicidal thoughts and behaviors.
In short-term studies, antidepressants increased the risk of suicidal tendencies in some children and young adults with depression or psychiatric disorders.
MAOIs and Drug Interactions
MAOIs can cause serious reactions if you take them with certain other drugs.
Be sure to tell your doctor and pharmacist all the medications you’re taking before you take an MAOI.
This includes prescriptions and over-the-counter medications, vitamins and other dietary supplements (nutritional shakes, protein powders, etc.), herbal remedies, and illegal or recreational drugs.
Certain foods and drinks can cause dangerous reactions if they’re taken with an MAOI.
Your physician will probably tell you to avoid foods that contain high levels of tyramine, dopamine, and tryptophan.
Some restricted foods may include:
- Aged cheeses
- Cured meats and certain other meat products
- Fermented sausages such as pepperoni, salami, and bologna
- Beef or chicken liver
- Shrimp paste
- Draft beer and red wine
- Certain liqueurs
- Fermented soy products, such as soy sauce, miso, or tofu
- Certain fruits, such as bananas, raspberries, dried fruits, or overripe fruits
- Fava beans
- Caffeinated beverages, such as coffee, tea, or cola
Talk to your doctor about all dietary restrictions before taking an MAOI, and make sure you understand which foods and drinks to avoid.
MAOIs and Pregnancy
Since there is so little known about the effects of MAOIs on a developing baby, doctors generally avoid prescribing them during pregnancy or breastfeeding.
Also, MAOIs may interact with other medications that you may need during labor and delivery.
Monoamine oxidase inhibitors
Monoamine oxidase inhibitors (also called MAO inhibitors or MAOIs) block the actions of monoamine oxidase enzymes.
Monoamine oxidase enzymes are responsible for breaking down neurotransmitters such as dopamine, norepinephrine, and serotonin in the brain. Low levels of these three neurotransmitters have been linked with depression and anxiety. By blocking the effects of monoamine oxidase enzymes, MAOIs increase the concentration of these three neurotransmitters and are useful at relieving symptoms associated with depression, such as sadness or anxiety.
MAOIs are typically only used when other antidepressants have proven ineffective, because they have a higher risk of drug interactions than standard antidepressants and can also interact with certain types of food such as aged cheeses and cured meats. They also tend to have more side effects than standard antidepressants and may cause a withdrawal syndrome on discontinuation.
What are Monoamine Oxidase Inhibitors used for?
MAOIs may be used to treat the symptoms of depression, such as sadness, anxiety, or worry, that have not responded to other antidepressants. They should not be used to treat severe depression or bipolar disorder.
There are some other drugs that also inhibit monoamine oxidase enzymes (in addition to having other properties), but are not used for the treatment of depression. These drugs should not be taken within 14 days of another MAOI nor with food or beverages that have a high tyramine content. Some resources may not list these drugs as MAOIs even though they inhibit monoamine oxidase enzymes. Examples include:
- Linezolid (Zyvox): an antibiotic used to treat certain bacterial infections that are resistant to other antibiotics
- Methylene blue (Provayblue): a potent MAOI that is used to treat drug-induced methemoglobinemia (a condition where an inefficient form of hemoglobin is present in large quantities in the blood)
- Procarbazine (Matulane): Used in addition to other medications to treat Hodgkin’s disease
- Rasagiline (Azilect): Used to treat symptoms of Parkinson’s disease
- Selegiline (Eldepryl, Zelapar): May be used for the treatment of Parkinson’s disease in addition to other medications.
What are the differences between Monoamine Oxidase Inhibitors?
All three MAOIs (isocarboxazid, phenelzine and tranylcypromine), available in the U.S. and used for the treatment of depression, are irreversible inhibitors of the enzyme monoamine oxidase. Irreversible means that the body must regenerate new monoamine oxidase enzymes to resume previous levels of enzymatic activity. This can take weeks, which means that the effects of MAOIs persist long after the drugs have been cleared from the body.
Phenelzine may be more likely to cause sedation and weight gain than isocarboxazid or tranylcypromine.
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Are Monoamine Oxidase Inhibitors safe?
When taken at the recommended dosage, MAOIs are considered safe. However, they are potentially fatal in overdose and have also been associated with a few serious, potentially fatal, side effects such as:
- Very severe drug interactions. Since the effects of MAOIs persist for several weeks after the last dose is taken, at least a 14-day washout period is required before starting any other type of antidepressant or medicine that also increases levels of serotonin or other chemical neurotransmitters
- Very severe food interactions. Extremely high blood pressure, which could lead to a fatal stroke, may result if foods high in tyramine such as aged cheeses, fermented meats, Fava or broad beans, beer, marmite, or soy sauce, are consumed while taking MAOIs
- An increase in suicidal thoughts and behaviors, particularly in children and young adults under the age of 25 years. This is most likely to occur when starting therapy
- Serotonin syndrome, usually when MAOIs are taken in conjunction with other medicines or supplements that also increase serotonin, or when taken at high dosages. Symptoms include confusion, restlessness, muscle jerking, and excessive sweating
- Rarely, rapid but transient increases in blood pressure within 30 minutes to two hours of MAOI ingestion.
MAOIs should not be given to people with heart disease or high blood pressure, or to people with pheochromocytoma. They should be discontinued 10 days prior to elective surgery.
What are the side effects of Monoamine Oxidase Inhibitors?
One of the more common side effects associated with MAOIs on drug initiation is low blood pressure when going from a standing to a sitting position (called orthostatic hypotension). In most people this can be managed by slowly increasing the dosage of the medication, giving split doses, and increasing fluid intake.
Other common side effects when starting therapy include:
Insomnia may be helped by not giving doses too late in the evening.
Side effects that tend to occur with regular, long-term therapy include:
- Edema (fluid retention)
- Muscle pains
- Myoclonus (spasmodic, jerky, muscle contractions)
- Paraesthesias (abnormal sensations or prickling in the nerves)
- Sexual dysfunction
- Weight gain.
Paraesthesias may be helped by pyridoxine supplementation.
For a complete list of side effects, please refer to the individual drug monographs.
Vitamin E: Taking vitamin E with a blood-thinning medication such as Coumadin can increase anti-clotting activity and may cause an increased risk of bleeding.
Ginseng: This herb can interfere with the bleeding effects of Coumadin. In addition, ginseng can enhance the bleeding effects of heparin, aspirin, and nonsteroidal anti-inflammatory drugs such as ibuprofen, naproxen, and ketoprofen. Combining ginseng with MAO inhibitors such as Nardil or Parnate may cause headache, trouble sleeping, nervousness, and hyperactivity.
Ginkgo Biloba: High doses of the herb Ginkgo biloba could decrease the effectiveness of anticonvulsant therapy in patients taking the following medications to control seizures: Tegretol, Equetro or Carbatrol (carbamazepine), and Depakote (valproic acid).
Drugs with Other Drugs
Two out of every three patients who visit a doctor leave with at least one prescription for medication, according to a 2007 report on medication safety issued by the Institute for Safe Medication Practices. Close to 40 percent of the U.S. population receive prescriptions for four or more medications. And the rate of adverse drug reactions increases dramatically after a patient is on four or more medications.
Drug-drug interactions have led to adverse events and withdrawals of drugs from the market, according to an article on drug interactions co-authored by Shiew-Mei Huang, Ph.D., deputy director of FDA’s Office of Clinical Pharmacology. The paper was published in the June 2008 issue of the Journal of Clinical Pharmacology.
However, market withdrawal of a drug is a fairly drastic measure. More often, FDA will issue an alert warning the public and health care providers about risks as the result of drug interactions.
Examples of drug interactions with other drugs …
Cordarone (amiodarone): FDA issued an alert in August 2008, warning patients about taking Cordarone to correct abnormal rhythms of the heart and the cholesterol-lowering drug Zocor (Simvastatin). Patients taking Zocor in doses higher than 20 mg while also taking Cordarone run the risk of developing a rare condition of muscle injury called rhabdomyolysis, which can lead to kidney failure or death. “Cordarone also can inhibit or reduce the effect of the blood thinner Coumadin (warfarin),” said Huang. “So if you’re using Cordarone, you may need to reduce the amount of Coumadin you’re taking.”
Lanoxin (digoxin): “Lanoxin has a narrow therapeutic range. So other drugs, such as Norvir (ritonvair), can elevate the level of Lanoxin,” says Huang. “And an increased level of Lanoxin can cause irregular heart rhythms.” Norvir is a protease inhibitor used to treat HIV, the virus that causes AIDS.
Antihistamines: Over-the-counter (OTC) antihistamines are drugs that temporarily relieve a runny nose, or reduce sneezing, itching of the nose or throat, and itchy watery eyes. If you are taking sedatives, tranquilizers, or a prescription drug for high blood pressure or depression, you should check with a doctor or pharmacist before you start using antihistimines. Some antihistamines can increase the depressant effects (such as sleepiness) of a sedative or tranquilizer. The sedating effect of some antihistamines combined with a sedating antidepressant could strongly affect your concentration level. Operating a car or any other machinery could be particularly dangerous if your ability to focus is impaired. Antihistamines taken in conjunction with blood pressure medication may cause a person’s blood pressure to increase and may also speed up the heart rate.
Tips to Avoid Problems
There are lots of things you can do to take prescription or over-the-counter (OTC) medications in a safe and responsible manner.
- Always read drug labels carefully.
- Learn about the warnings for all the drugs you take.
- Keep medications in their original containers so that you can easily identify them.
- Ask your doctor what you need to avoid when you are prescribed a new medication. Ask about food, beverages, dietary supplements, and other drugs.
- Check with your doctor or pharmacist before taking an OTC drug if you are taking any prescription medications.
- Use one pharmacy for all of your drug needs.
- Keep all of your health care professionals informed about everything that you take.
- Keep a record of all prescription drugs, OTC drugs, and dietary supplements (including herbs) that you take. Try to keep this list with you at all times, but especially when you go on any medical appointment.
MAO inhibitors: Risks, benefits, and lore
Monoamine oxidase (MAO) inhibitors were the first drugs for treating depression. Introduced in the 1950s, they were used extensively for the next two decades. Their use declined substantially since then because of their reported side effects, their food and drug interactions, and the introduction of new classes of antidepressants.
This trend may be changing. These drugs can be effective in major depressive disorder, and particularly in major depressive disorder with atypical features and in treatment-resistant depression.
New, selective MAO inhibitors are being developed. Moreover, the selegiline transdermal system (Emsam),1,2 introduced in 2006, offers the potential advantage of eliminating the need for burdensome dietary restrictions and has renewed interest in this group of drugs.
In this article, we discuss the history, pharmacology, safety and tolerability of MAO inhibitors, and we summarize recent MAO inhibitor research. Our goal is to familiarize physicians with this class of drugs, including recent updates regarding their safety profile and liberalized dietary recommendations.
DEPRESSION IS COMMON, DIFFICULT
Depression affects 121 million people worldwide.3 According to a study that compared two surveys of 40,000 people each, the prevalence of major depressive disorder in the United States more than doubled (from 3.3% to 7.0%) from 1992 to 2002.4 Another survey, in 2002 and 2003, revealed the lifetime prevalence of major depressive disorder to be 16.6%.5
Treatments for depression have expanded over the past 20 years, with new classes of drugs such as selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). However, depression has remained a difficult condition to treat. In the National Institute of Mental Health’s Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study,6 the remission rate in patients treated with the SSRI citalopram (Celexa) for up to 14 weeks was 28% using one measure and 33% using another. Diversifying and understanding existing and emerging therapeutic options is important to the effective treatment of this disease.
THE RISE AND FALL OF MAO INHIBITORS
The first antidepressant introduced was an MAO inhibitor, iproniazid, followed shortly thereafter by a tricyclic antidepressant, imipramine (Tofranil). When iproniazid, originally an antituberculosis agent, was promoted for its antidepressant properties in the 1950s, very little was known about its side effects. It was later removed from the market because of hepatotoxicity, but several other MAO inhibitors had surfaced for the treatment of depression—eg, phenelzine (Nardil), isocarboxazid (Marplan), and tranylcypromine (Parnate).
Currently, MAO inhibitors are typically reserved for third- or fourth-line treatment. As a result, even psychiatrists have little experience with these agents. In a 1999 survey of the Michigan Psychiatric Association,7 12% of practicing psychiatrists said they had never prescribed an MAO inhibitor, another 27% had not prescribed one in the prior 3 years, and only 2% said they prescribed them frequently. A decade earlier, about 25% had said they prescribed them often.8
The prescription rate of MAO inhibitors has remained low during the past 10 years. In a Canadian population-based study9 conducted among older adults in a large health care database from January 1997 to April 2007, the yearly incidence of MAO inhibitor prescriptions decreased from a rate of 3.1 per 100,000 to 1.4 per 100,000. Drug interactions, side effects, preference for other treatments, and dietary restrictions were the reasons most often cited for not prescribing these drugs.7
The side effects of MAO inhibitors were recognized by the mid-1960s, when more than 40 cases of tyramine-induced hypertensive crisis were reported (particularly with tranylcypromine).10,11 Many of the reported events happened after the patient ate tyramine-rich foods such as aged cheese (hence, “the cheese reaction”—more on this below) or drank draft beer.10,11 The US Food and Drug Administration (FDA) consequently established dietary restrictions for patients taking MAO inhibitors, but people found the guidelines cumbersome and often switched to newer drugs that did not require a restrictive diet, such as tricyclics and, much later (in the 1980s), SSRIs.
MAO HAS TWO SUBTYPES
MAO is a flavin-containing enzyme critical for regulating neurotransmitter levels by catabolizing endogenous monoamines (eg, norepinephrine, serotonin, and dopamine) and exogenous amines (eg, dietary tyramine). It is found throughout the body but is more highly concentrated in the liver, kidneys, intestinal wall, and brain.
MAO has two subtypes, isoenzyme A (MAO-A) and isoenzyme B (MAO-B), which vary in their distribution. MAO-A is found primarily in the intestinal tract, liver, and peripheral adrenergic neurons (adrenal glands, arterial vessels, and sympathetic nerves) and preferentially metabolizes serotonin and norepinephrine. MAO-B is found mostly in the brain and liver. However, both isotypes are found in all of the areas mentioned. Since 80% of intestinal MAO is MAO-A, this isoenzyme is primarily responsible for degradation of tyramine, and thus inhibition of MAO-A is associated with the cheese reaction.10,11
MAO inhibitors: the forgotten antidepressant that saved my life
Cheese contains tyramine, a compound found in many foods that has been linked to headaches in migraine sufferers. For people on an MAOI, eating products with tyramine can cause a rapid and dangerous rise in high blood pressure that can result in a fatal stroke. Aged cheeses, such as cheddar, are especially high in tyramine. People who take MAOIs are advised not to eat aged cheese (cottage, cream cheese and farmer’s cheese are allowed), fava or broad beans, sauerkraut, pickles, olives, soy sauce, teriyaki sauce, tap beer, vermouth or red wine and to limit their intake of chocolate, caffeinated beverages, yogurt, sour cream, avocados and raspberries.
MAOIs also interact with both prescription and over-the-counter medications. You can’t take an antihistamine such as Sudafed and have to remind your dentist not to use Novocain to avoid an interaction that could cause a hypertensive crisis.
The MAOIs available today include Nardil (phenlzine) and Parnate (tranylcypromine). “They have been around for decades. They are just as effective as Tofranil or Prozac,” Dr. McGrath notes. “In terms of treating depression and panic disorder, we have made no progress in efficacy since the 1960s.”
In 2006, a MAOI patch called Emsam TD (selegiline transdermal) was approved. Patient wear a patch that administers selegiline, a drug used to treat Parkinson’s disease, through the skin and into the bloodstream. Patients on low doses of Emsam do not have to follow any dietary restrictions. However, at higher doses, the FDA recommends patients follow the MAOI dietary restrictions.
Despite its favorable side effect profile and efficacy, Emsam is rarely used. “Most patients and psychiatrists are not used to patches. Emsam is also expensive ($450 a month), and most insurance companies do not cover it,” Dr. McGrath said. “It’s a shame because they are effective and well-tolerated by patients, with few side effects.”
Giving SSRIs a try
Today SSRIs are still the first line of treatment for patients with depression and panic disorder. Although they have side effects, including delayed ejaculation in men and difficulty achieving orgasms in women, they only need to be taken once a day and can be prescribed by internists.
A few years Prozac was approved in 1987, I decided to give it a try. I missed eating pizza. In order to go on Prozac, I had to stop taking Nardil and be off it for two weeks. But Prozac was too stimulating for me. I could not go above 2 mg, and the standard dose was 20 mg. When Zoloft was approved, I tried that. But it gave me panic attacks and I couldn’t sleep. This was a huge disappointment to me as I was working at Pfizer at the time, which marketed Zoloft, and knew that it was effective as Prozac but had a low agitation rate of only 2 percent. Unfortunately I was among the 2 percent and advised never to take an SSRI again. So I went back on Nardil, and that’s what I take today along with low doses of Xanax (alprazolam), an anti-anxiety medication.
Dr. Brunswick said I am his only patient on an MAOI. Although he has offered it to patients who failed on other medications he told me they are reluctant to try it because of the dietary restrictions and the drug interactions that can occur.
A case for MAOIs
Despite the downsides of MAO inhibitors, I have made my peace with it. I would rather take Nardil then have panic attacks. I wear a MedicAlert tag that says I take MAO inhibitors and I carry around a blood pressure medication in case I accidentally eat a food or take a medication that interacts with Nardil. Since I started to take Nardil, I have never had a problem or had to raise my dose. In fact, I have lowered my dose substantially over the years. I believe for people who don’t respond to other medications for depression and panic attacks, it’s a good alternative.
Both Drs. McGrath and Brunswick say MAOIs should be used more.
“I have had patients with depression who have been given electroconvulsive therapy (ECT) and it did not make them better,” Dr. McGrath said. “But they responded well to MAOIs. I wish more doctors considered trying an MAOI first before going to ECT.”
Dr. Brunswick notes that with patients whose symptoms are not totally relieved by Prozac or Zoloft, psychiatrists often add antipsyhotic drugs such as Seroquel (quetiapine) to their medication regimen, but these can cause extreme weight gain and metabolic disorders such as diabetes. “Everyone is looking at alternative treatments for depression and other mental illnesses, including transcranial magnetic stimulation and ketamine,” he said. “No one knows how well these new treatments will work, but we do know that MAOIs work, and they are as effective as any existing treatment for both depression and panic disorder.”
Elsevier Connect Contributor
David Levine (@Dlloydlevine) is co-chairman of Science Writers in New York (SWINY) and a member the National Association of Science Writers (NASW). He served as director of media relations at the American Cancer Society and as senior director of communications at the NYC Health and Hospitals Corp. He has written for Scientific American, the Los Angeles Times, The New York Times, More magazine, and Good Housekeeping, and was a contributing editor at Physician’s Weekly for 10 years. He has a BA and MA from The Johns Hopkins University.
Monoamine oxidase inhibitors (MAOIs) for depression
Monoamine oxidase inhibitors (MAOIs) were the first antidepressants to be developed. They are sometimes referred to as irreversible monoamine oxidase inhibitors, and can be used to treat depression in adults.
These days, MAOIs are not often prescribed as the first treatment for depression. That’s because of their potential for serious side effects and interactions with certain foods and other medicines. However, they can be useful in treating depression when newer, safer antidepressants have not been effective.
MAOIs can also be used to treat some anxiety disorders, but again, they are not usually the first choice medicine because of the associated risks of the side effects and interactions.
MAOIs available in Australia
There are 2 types of MAOI available in Australia:
- phenelzine (brand name Nardil); and
- tranylcypromine (brand name Parnate).
Both are available as tablets.
How do MAOIs work?
Depression is associated with reduced levels of chemicals in the brain that transmit signals between nerve cells. These chemicals are called neurotransmitters. MAOIs increase the levels of these neurotransmitters in the brain by blocking their breakdown.
MAOIs work by blocking the monoamine oxidase enzyme, which is involved in the breakdown and removal of several of the neurotransmitters – namely, dopamine, noradrenaline and serotonin.
Diet and MAOIs
MAOIs also block the breakdown of a substance called tyramine. Tyramine is found naturally in the body as well as in certain foods and drinks, and is involved in regulating blood pressure.
Eating high-tyramine foods while taking a monoamine oxidase inhibitor can cause tyramine levels in the body to rise to dangerous levels. This can cause sudden and severe elevations in blood pressure.
People taking MAOIs need to follow a strict diet, which involves avoiding foods and drinks containing a large amount of tyramine.
What foods should be avoided when taking MAOIs?
Some of the foods and drinks that are high in tyramine and should be avoided while taking MAOIs (and for 2 weeks after stopping taking them) include:
- matured (aged) or strong cheeses or out-of-date cheeses;
- certain meats (e.g. salami, pepperoni, mortadella);
- pickled herring;
- pâté and liver;
- Vegemite and other concentrated yeast extracts (Promite, Marmite, Bovril);
- protein extracts;
- soy sauce and other soybean products, such as miso and tofu;
- banana skins, banana chips and banana-flavoured desserts (banana peel is used in flavouring);
- fava or broad bean pods;
- fermented soya beans; and
- beer and wine.
In addition, foods such as meat, fish, poultry and eggs can contain high amounts of tyramine if they have not been stored correctly and have gone off. Excessive amounts of chocolate and caffeine should also be avoided.
If you consume any of these foods while taking a MAOI, your blood pressure may rise rapidly and you may get severe symptoms such as a throbbing headache, nausea, vomiting, or a fast heartbeat. Such a situation is a medical emergency and can be very dangerous if not treated properly. If you have a reaction after eating any of these foods, contact your doctor, call 000 for an ambulance or go to hospital immediately.
Your doctor should give you a list of all the foods and drinks you need to avoid while taking this medication. Even if you stop taking MAOIs, you’ll need to keep avoiding these foods and drinks for at least 14 days afterwards. You should also have a plan in case you accidently eat or drink something with a high level of tyramine.
MAOIs and other medicines
MAOIs interact with a long list of other medicines, so you must always check with your doctor or pharmacist before taking any other medicines, including non-prescription and complementary medicines.
It is especially important not to take certain other antidepressants when you are taking (or have recently been taking MAOIs), including SSRIs, SNRIs and tricyclic antidepressants. Painkillers such as pethidine and tramadol are other medicines that cannot be taken while you are on MAOIs. Taking these types of medicines together can cause a serious condition called serotonin toxicity.
You also should not take cold and flu preparations or any similar medicines while you are taking MAOIs, as you can develop very high blood pressure. Certain antihistamines used to treat allergies and hay fever also need to be avoided.
A variety of other medicines should also be avoided if you are taking MAOIs, including:
- some asthma medicines;
- blood pressure medicines;
- weight loss medicines; and
- some anaesthetic medicines, including certain local anaesthetics.
MAOIs also interact with illicit drugs such as amphetamines.
Your doctor or pharmacist should give you a list of all foods, drinks and medicines to avoid, and you should follow this list to the letter. Even after you stop taking MAOIs, you need to continue to avoid these foods and medicines for at least 14 days, as there is still a possibility of interactions during this period.
When you begin treatment, your doctor will recommend starting with a low dose. The dose is then gradually increased over several days.
MAOIs are taken several times per day, and the last dose should be taken no later than early afternoon to reduce the risk of having trouble sleeping at night.
It’s important that you don’t stop taking these antidepressants suddenly. Stopping MAOIs can be associated with developing flu-like symptoms, and the risk of this is higher if you stop them suddenly. Your doctor can advise on the best way to stop these medicines to avoid withdrawal symptoms. Talk to your doctor, and if your medicine needs to be stopped, they the dose should generally be reduced slowly.
Side effects of MAOIs
MAOIs are often not the first choice of antidepressant because they are associated with many side effects. Some of these side effects include:
- low blood pressure when standing up;
- dry mouth;
- insomnia (trouble sleeping);
- blurred vision;
- sexual problems;
- rapid heartbeat; and
- weight gain.
Who should not take MAOIs?
MAOIs should not be used by children and teenagers.
If you are pregnant or planning a pregnancy, let your doctor know, as it will impact on the type of medicine that your doctor prescribes. Your doctor will weigh up the risks and benefits of treatment for both you and your baby.
Breast feeding is not recommended if you are taking monoamine oxidase inhibitors.
Reversible inhibitors of monoamine oxidase (RIMAs)
There is another class of medicine that is similar to MAOIs – reversible inhibitors of monoamine oxidase type A (RIMAs). Moclobemide is the only medicine in this class available in Australia. Examples of brand names include Aurorix, Amira and Clobemix.
Moclobemide can be used to treat depression in adults. It can be especially helpful in people with symptoms of sleeping difficulties, anxiety and inability to concentrate. Moclobemide is generally well tolerated and is not subject to as many of the dietary restrictions as the MAOIs when taken in recommended doses.
How moclobemide works
Like the MAOIs, moclobemide works on brain chemicals, but it is more targeted. It inhibits just one of the 2 monoamine oxidase enzymes, blocking MAO type A but not type B.
This means that people taking moclobemide can generally still eat foods containing tyramine, because tyramine still gets broken down by MAO-B and doesn’t build up dangerously in the brain to cause high blood pressure. To be doubly sure, moclobemide is usually taken after food.
People taking moclobemide should still avoid cough and cold preparations that contain pseudoephedrine, and it is still prudent to check with your doctor or pharmacist before starting new prescription or over-the-counter medicines.
Moclobemide should be taken after meals twice a day.
Side effects of moclobemide
Most people experience few side effects with moclobemide. Side effects that are associated with moclobemide, including difficulty sleeping, dizziness, nausea and headache, usually go away after a while.
Moclobemide and other medicines
Moclobemide can interact with some other medicines, but not as many as MAOIs. Medicines that should be avoided while taking moclobemide include:
- St John’s wort;
- Triptans (medicines used in treating migraine);
- certain other antidepressants (including SSRIs, SNRIs and tricyclic antidepressants);
- some painkillers; and
- certain cough and cold medicines.
Switching antidepressant medicines
If you are changing antidepressants, your doctor will usually recommend slowly stopping the first medicine and then having a break before starting the new one. This is called a ‘washout period’, and it’s important because it prevents the antidepressants interacting, which can cause serious harm.
Depending on the antidepressants you are stopping and starting, the washout period may need to last for days or several weeks. The main concern is serotonin toxicity (also known as serotonin syndrome), which is an overload of serotonin in the brain.
Young people starting antidepressants
People younger than 25 years of age with depression may have a slightly increased risk of suicidal thoughts and behaviour when they first start taking antidepressants. So, close monitoring is needed in any young person taking antidepressants, especially when they are first started. Get help straight away if you experience any suicidal thoughts.
Last Reviewed: 20/08/2018