Final answer:
MAO-B inhibitors like selegiline increase neurotransmitter levels but can interact dangerously with drugs like meperidine, tramadol, cyclobenzaprine, and dextromethorphan, potentially leading to serotonin syndrome. They are often reserved for when other antidepressants are ineffective due to their potential for severe side effects and interactions.
Step-by-step explanation:
MAO-B inhibitors, such as selegiline, are medications that inhibit the activity of the monoamine oxidase B enzyme, which is responsible for breaking down certain neurotransmitters in the brain. By inhibiting this enzyme, selegiline increases the levels of neurotransmitters like dopamine, which can be beneficial in conditions like Parkinson's disease and as an adjunct treatment in major depressive disorder.
However, MAO-B inhibitors can have potentially dangerous interactions with several other medications. For example, combining MAO-B inhibitors with drugs like meperidine, cyclobenzaprine, tramadol, or dextromethorphan can lead to serious side effects due to excessive serotonin, norepinephrine, or dopamine in the brain. These MAOI interactions can lead to a condition known as serotonin syndrome which is characterized by high body temperature, agitation, increased reflexes, tremor, sweating, dilated pupils, and diarrhea.
Additionally, there are dietary restrictions associated with MAO inhibitors due to their ability to interact with tyramine, found in certain foods, which can cause hypertensive crises. Due to severe side effects and potential for these serious drug interactions, MAO-B inhibitors are often used when other antidepressants, such as tricyclic antidepressants or selective serotonin reuptake inhibitors (SSRIs), have not been effective.