MAOIs – Monoamine Oxidase Inhibitors.

MAOIs or monoamine oxidase inhibitors are among the earliest treatments used for depression. They rolled out of the laboratory soon after the tricylic antidepressants. The MAO inhibitors are quite effective but their use is reserved because of their potential side effects. 

What is Monoamine.

A monoamine is an amine compound which contains one amine group, which functions as neurotransmitter. Examples of monoamines are naturally occurring brain chemicals called neurotransmitters such as serotonin, dopamine, epinephrine and norepinephrine and which are responsible for transmission of brain signals.

What is Monoamine Oxidase (MAO).

Mono amine oxidase is a protein enzyme of the brain and liver which brings about the oxidation of the monoamine and deaminates it.

MAOI – Monoamine Oxidase Inhibitor.

A MAOI drug or monoamine oxidase inhibitor is a substance that inhibits the activity of monoamine oxidase thereby increasing the levels of monoamines in the brain. Increase in levels of monoamines like serotonin, dopamine and epinephrine helps to maintain the mood effect.

MAOIs can cause negative interactions (sudden rise in blood pressure) with other medications and certain types of food, especially those rich in tyramine. Such foods include cheese, chocolates, bananas, wines and chicken liver.

Such a reaction between such foods and MOAIs is called the “cheese effect”. Tyramine is a naturally occurring monoamine which acts as dopamine, epinephrine and norepinephrine releasing agent.

The positive side of MAOIs is that they can show positive results in certain forms of depression where other medications have been ineffective.

Uses of MAOIs.

Monoamine oxidase inhibitors are used in treatment of the following mental disorders.

• Depression
• Social anxiety
• Parkinson’s disease
• As an alternative to migraine prophylaxis.

How MAOIs Work.

MAOIs also act like other antidepressants but their action is on a wider range of neurotransmitters. Neurotransmitters are naturally occurring brain chemicals which are also called monoamines. They include serotonin, norepinephrine and dopamine. They act as messengers of the brain and responsible for maintaining the mood of the person and  lower levels of these substances lead to depression. Once they have played their function, they are burnt up causing their levels to fall. This is brought on by a protein called monoamine oxidase which is a liver and brain enzyme.

Monoamine oxidase inbitors, as the name suggests, block this action of monoamine oxidase leading to maintaining of adequate levels of the neurotransmitters in the brain. This gives a “good mood” to the depressed person.

Monoamine oxidase enzyme not only reduce the levels of the neurotransmitters but also of tyramine. Therefore rise in levels of the neurotransmitters is also associated with rise in levels of tyramine. This can be dangerous.

Though high levels of neurotransmitters are beneficial, simultaneous increase in tyramine can be disastrous as this can cause high spikes in blood pressure which can even lead to brain hemorrhage (bursting of an artery) due to interaction between MAOIs and tyramine.

MAOI List.

Below is the MAOI list or examples of MAOIs which are used in treatment of certain mental conditions.

          Generic names and brand names.

• Phenezil – Nardil.
• Tranylcypromine – Parnate
• Isocarboxazid – Marplan
• MAOI patch:  Selegiline – Emsam.  This is newer MAOI which is stuck to the skin as a patch and not swallowed. It is believed to cause fewer side effects than other MAOIs.

Side Effects of MAOIs.

Common side effects of MOAIs or monoamine oxidase inhibitors include

• Headache
• Nausea
• Restlessness
• Dizziness
• Insomnia
• Increased appetite leading to weight gain
• Drowsiness but difficulty if falling asleep
• Blurred vision
• Sexual problems
• As explained above, sudden increase in blood pressure with certain foods.
• There maybe withdrawal symptoms and therefore this drug is to be withdrawn in tapering doses.

Precautions with MAOIs|Interactions with other Drugs.

If you are taking MAOIs, the following precautions should be taken.

• Do not eat foods containing tyramine (explained above) If you are on MAOI, make sure you get a complete list of such foods from your doctor.
• MAOI and alcohol. Do not drink alcohol or any non alcoholic fermented drinks. Drinking alcohol when on MAOIs can make you feel drowsy. Even moderate drinking of alcohol can delay the therapeutic effect of antidepressants.
• Do not smoke cannabis. The effect is unpredictable.
• MAOI and Smoking. Do not smoke tobacco as the addictive potential of smoking  is worsened with MAOIs.
• MAOI interaction with other antidepressants. Combining MAOIs with certain other antidepressant can be dangerous. Combination of SSRIs and MAOIs can lead to a life threatening condition called serotonin syndrome. A period of at least five weeks has to elapse if you are switching from SSRIs to MAOIs.
• MAOI interaction with other drugs. When on MAOIs, do not take other medicines such as painkillers, medicines for cold, weight loss pills and stimulants
• Stick to your dose. Overdose can cause death.

Call medical help, if you develop the following when on therapy with MAOI:

• Allergic reaction such as a hive or a swollen face opr lips.
• Stiff neck
• Chest pain
• Fast or slow heart beat
• Severe headache
• Vomiting
• Breathing difficulty

Related posts:

1. Methotrexate Uses and Side Effects.
2. Cyclosporine Uses, Side Effects and Precautions.
3. Antihistamine Uses, Side Effects and Contraindications.
4. Melatonin for Sleep – Uses, Side Effects and Contraindications.
5. Benzodiazepine Sleeping Pill – Use, Side Effects and Contraindications.
6. 13 Side Effects of Chemotherapy.
7. Side Effects of Radiation Therapy.
8. Cinnamon – Side Effects.