Final answer:
MAOIs are antidepressants that increase neurotransmitter levels by inhibiting the monoamine oxidase enzyme. They are used primarily when other treatments fail and can treat depression with atypical features, anxiety, and phobias. Due to safety concerns, they are prescribed less frequently and require dietary and medication restrictions.
Step-by-step explanation:
Monoamine Oxidase Inhibitors: Monoamine oxidase inhibitors (MAOIs) are a class of drugs that include isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), selegiline (Emsam), and moclobemide (Amira). These antidepressants work by inhibiting monoamine oxidase, an enzyme responsible for breaking down neurotransmitters such as dopamine, serotonin, and norepinephrine. By preventing the breakdown of these neurotransmitters, MAOIs increase their levels in the synaptic cleft, which can alleviate symptoms of depression. Although these drugs were among the first antidepressants to be used, they are now typically reserved for cases where other treatments have been ineffective due to potential toxicities and harmful interactions with certain foods and other drugs. MAOIs were once also used to treat hypertension, but their use in this area has become limited. Clinically, MAOIs are most beneficial for treating certain neurotic illnesses, depression with atypical features, anxiety, and phobias. While major depression might not always be the primary indication, these drugs can be particularly effective for specific subsets of patients. Potential toxicities of MAOIs include severe high blood pressure episodes triggered by certain foods containing tyramine (such as aged cheese and red wine), as well as interactions with other medications. Symptoms of an MAOI overdose may include muscle stiffness, fever, and confusion, which could lead to a life-threatening condition known as serotonin syndrome.