MAOIs inhibit monoamine oxidase (MAO) in the
brain. As MAO catabolizes serotonin,
norepinephrine, and dopamine, treatment with an
MAOI leads to increased amounts of these
neurotransmitters.
III. Indications
A. Atypical depression: i.e., a depression
characterized by non-autonomous depression, high
levels of anxiety, great lethargy when depressed,
overeating and oversleeping.
B. Hysteroid dysphoria (a subtype of atypical
depression): i.e., a depression in patients who
are characterized by flamboyance, seductiveness,
marked vulnerability to personal rejection with
dramatic crashes in mood. Such patients often
report extreme lethargy when depressed (leaden
paralysis), retreating to bed, and oversleeping
and often overeating. The depression is often
reversible if the patient receives positive social
input from a new boyfriend for example.
C. Bulimia: an eating disorder which many
psychiatrists is closely related to depression,
frequently responds to treatment with MAOIs.
D. Depression in the elderly. Excessive levels of
monoamine oxidase activity have been demonstrated
in depressed geriatric patients. Many such
patients do very well when treated with MAOIs.
E. Panic disorder. While panic attacks can be
controlled by the use of benzodiazepines such as
Xanax, and by tricyclic antidepressants such as
Tofranil, many psychiatrists consider MAOIs to be
the drugs of choice in blocking panic attacks in
patients with severe Panic Disorder.
F. Social phobias. Individuals with phobias
regarding eating, writing or appearing in public
often respond better to MAOIs than to other
psychopharmacologic agents.
IV. Dosing
A. Despite the doses listed in PDR, adults usually
require a daily dose of at least 1 mg/Kg. of
Parnate, Nardil or Marplan..
Pediatric doses are usually stated as 0.3 to 1
mg/Kg, but larger doses may be necessary.
V. Duration of treatment
As relapse of depression is common in the first
two years after an index episode, it is often
suggested that patients remain on MAOIs for at
least two years. Patients who have had three or
more episodes of depression are candidates for
lifetime prophylactic medication. Lithium or
MAOIs may be employed for long-term therapy.
VI. Laboratory monitoring of MAOI therapy
A. Routine tests to detect adverse effects on the
bone marrow,liver etc
CBC, Chemscreen and urine analysis should be
obtained every 6 months.
B. Measurements of platelet MAO activity. Platelet
MAO activity has been shown to be highly
correlated with MAO activity in the brain. by
measuring the degree of inhibition of platelet MAO
one may titrate the dose of an MAOI. MAOIs are
maximally effective only when there is an 80% or
greater inhibition of platelet MAO
VII. Adverse Effects - With incidence over 10%
Anorgasmia
Blurred vision
Drowsiness/sedation
Excitement/hypomania
Headache
Insomnia
Nausea
Orthostatic hypotension (While hypertension
Tachycardia is feared, hypo-
Weight Gain tension is a greater
problem for many
more patients.)
The adverse effects that most frequently lead
patients to prematurely discontinue MAOI therapy
are:
Anorgasmia
Edema
Hypomania
Insomnia
Orthostatic hypotension
Weight gain
VIII. Drug-Food Interactions
The fermentation of protein liberates tyramine, an
amino acid that has indirect sympathomimetic
effects. Among some of the foods highest in
tyramine are:
Aged cheeses (e.g. blue, cheddar, Parmesan,
Stilton, Swiss)
Pickled herring, pickles, sauerkraut.
Aged sausages such as hard salami, bologna,
mortadella, pepperoni
Sour cream
Overripe fruit, especially bananas and
avocados
Red wine, beer, sherry, liqueurs
Caviar, escargot, anchovies
If a food high in tyramine is ingested the patient
may experience a hypertensive episode
characterized by a severe occipital headache,
stiff neck, nausea, vomiting, constricting chest
pain, dilated pupils, and tachycardia.
Patients may be prescribed Nifedipine 10 mg
capsules and instructed that if they experience
the symptoms of a hypertensive episode that they
should bite into a capsule and immediate swallow
it. They should also head for a hospital E.R.
where more definitive treatment is available.
IX. Drug-Drug Interactions
Amipaque - Potentiation of seizure-inducing
properties (used in myelography).
Alcohol, barbiturates, anesthetics - increased CNS
depression.
Anti-cholinergics - increased atropine-like
effects.
Buspar - hypertension reported
Demerol - Absolutely contraindicated. Demerol is
responsible for more deaths in patients taking
MAOI than all other drugs combined.
Narcotics - Codeine or morphine may be used. As
potentiation is possible start by reducing usual
dose by 50%. Titrate dose according to patient's
response.
Over-the-counter drugs to be avoided are:
Cold remedies containing decongestants
Appetite suppressants such as Dexatrim
Anti-asthma drugs such as Primatine
Cough medications containing dextro-
methorphan.
Prozac and other selective serotonin reuptake
blockers such as Zoloft and Paxil may cause a
fatal serotonin syndrome characterized by CNS
irritability, increased muscle tone, myoclonus,
diaphoresis, and hyperpyrexia.
Succinylcholine - Prolonged apnea a possibility
Sympathomimetics
Indirect: such as: amphetamine, methyl-
phenidate, ephedrine, pseudoephedrine, phenyl-
propanolamine, dopamine, tyramine are DRAMATICALLY
potentiated.
Direct: such as epinephrine, isoproterenol,
norepinephrine, and methoxamine are less
dramatically potentiated but should be avoided
except in emergency situations.
Tricyclic antidepressants - Dangerous if started
while a patient is on an MAOI but safe if started
with the MAOI or if the MAOI is started after the
tricyclic drug has been started.
X. Overdose
A syndrome characterized by insomnia, restlessness,
anxiety and at times agitation has been reported
in patients taking an overdose. Mental confusion,
and incoherence may be seen. While hypertension
is possible, hypotension is seen more often.
Hyperpyrexia may be severe and should be treated
with external cooling.
XI. Use in Pregnancy and lactation
A. Use in Pregnancy
The safety of MAOIs in pregnancy is unknown.
B. Use in nursing mothers
The American Academy of Pediatrics considers
Parnate therapy to be compatible with breast
feeding even though small amounts of the drug are
found in breast milk
XII. Future developments
A reversible inhibitor of monoamine oxidase
(RIMAO) has been developed. This drug.
moclobemide, will make MAOI therapy easier as
there are no food restrictions as long as the drug
is taken at the end of meals and no foods high in
tyramine are eaten for the next 3-4 hours.
Moclobemide has many fewer side effects than the
conventional MAOI. Insomnia, the most common side
effect, is reported by less than 10% of those who
have been treated to date. This drug seems to be
especially useful for the treatment of long-
standing mild depressions (dysthymia) that do not
respond to other antidepressan
