BLOG No. NINETEEN

I thought perhaps I would take a break from discussing cases talk about some side effects of some of the medicines that are used to decrease D2 dopamine. The vast majority of my patients tolerate the medicines just fine, but I want to be honest and have full disclosure. I would like to commit this blog to the direct D2 dopamine suppressors, discussing possible side effects for those of you that are interested.

But before I do that, I need to teach my readers little neuroanatomy. (The way the brain is built). There are four major neurological tracts of the brain and they are as follows. First, there is the mesocortical tract, which is the tract that brings us our affect. Our affect includes the facial expressions, gestures, and posture we show to others when experiencing emotions. For example, imagine running into an old friend you haven’t seen a while. The look on your face, is your affect.

If one of the D2 dopamine drugs accidentally bleeds into this tract, it can blunt your affect. It’s the facial expression of a sports fan whose team has a 95% chance of winning—but loses in the final seconds of overtime. Their face becomes emotionless.

The second of four tracts is called the mesolimbic tract. The limbic system is the neurological center for joy. And when this tract it is affected by dopamine meds, a person loses his joy. I remember watching films in college, back when dinosaurs roamed the earth, regarding the mental institutions of the 1950s and 60s, where the old D2 dopamine meds like Thorazine and Haldol were used. Patients wandered the halls of the institution with flat affect and no joy. Many patients stopped their medicines, as they would rather hear voices then lose their joy. Though we rarely use those medicines anymore, the newer D2 drugs can occasionally bleed into this tract and people lose their ability to feel joy.

But understand, this is extremely rare.

A third track requires the reader to read a B.A.W. Not familiar with that term? That stands for big-ass-word! Tubuloinfundibular. See, told you. This tract is the dopamine tract responsible for making breast milk. (No kidding, I wouldn’t make this stuff up). So when a D2 med bleeds into this track, milk can be produced—yes in boys and girls. Risperdal (risperidone) is the most common medicine to do this, though it’s usually only at extremely high doses used for schizophrenia.

In the last of the four neurological tracts I wish to discuss is the niagrostriatal pathway. This is the tract for movement. Damage to this pathway causes Parkinson’s disease. And accidental irritation by a dopamine medication can make people feel like they just have to move—kind of like reggae music, but not as pleasant. Neurologists call this sensation akisthesia. Abilify is one of the more common drugs to cause this, but it only happens in 3-4% of those who take it. But the good news is once you stop the medication, the side effect goes away.

Well evening here on our last night in Cabo has the sun setting in the distance. And a magical fairy has changed my Chardonnay into a gin and tonic. So until next time, when we discuss the side effects of the anti-seizure meds that balance GABA and glutamate, this is Dr. G saying, keep the faith.