I'm Dr. Shukle. Let’s talk about monoamine oxidase inhibitors today.
The monoamine oxidase inhibitors are drugs that inhibit the breakdown of norepinephrine and serotonin in the presynaptic neuron.
This allows more of these neurotransmitters in to the synaptic cleft.
The increase amounts of norepinephrine and serotonin are stored in the vesicles
and then they're eventually released when the nerve fires.
We have several types of monoamine oxidase inhibitors.
They can be nonselective or selective.
The nonselective agents are seen here, there's many of them, there's over twenty MAO-A, MAO-B inhibitors.
We also have selective agents.
The monoamine oxidase A inhibitors like maclobemide are some of the earliest antidepressants that we've ever used.
This particular drug was sold commercially as Mannerix.
Selective monoamine oxidase type B inhibitors include drugs like selegiline.
These are also commonly used – we see them still being used today.
Side effects to these medications are usually due to increase amounts of norepinephrine in the nerve terminals themselves
so this can include peripheral autonomic sympathomimetic effects.
This can lower your blood pressure and it can also increase your risk of seizures by lowering the seizure threshold.
Now, what's up with the blood pressure?
I just finished saying that there was more norepinephrine in the synaptic cleft.
If it’s sympathomimetic, it should cause more blood pressure and higher blood pressure.
Well in the absence of an indirect sympathomimetic, monoamine oxidase inhibitors
actually cause a drop in blood pressure, that’s a little bit hard to remember.
In the presence of an indirect sympathomimetic monoamine oxidase inhibitors cause a rise in blood pressure.
Monoamine oxidase inhibitors, I'll say MAOIs from now on, may cause severe hypertension in patients taking things like tyramine.
Tyramine is metabolized by monoamine oxidase.
Tyramine is found in things like aged-cheeses, soybeans, beers, and red wine, cured and processed meats.
So when you're talking about a wonderful Charcuterie board like this, you're talking about a tyramine overload.
If you have this kind of a picnic or a romantic dinner and you're on a monoamine oxidase inhibitor,
you can run into the risk of having very high blood pressures in the presence of those drugs.