Posts Tagged ‘neurotransmitter dopamine’
By Trevor Shewfelt, Pharmacist at the Dauphin Clinic Pharmacy
Honk, Honk, Honk. I hate it when I accidentally hit the panic button on my car fob. I was inside my car but, as the car was in the garage everything was very, very loud. I hit the panic button again to turn off the honking. The honking didn’t stop. I hit the unlock button on the car fob. The honking didn’t stop. I got out of the car. It was even louder outside the car. The horn was going off, lights were flashing, and I started to panic. Then I noticed that the lights weren’t just flashing on my car. They were flashing on my wife’s car as well. I ran back into the house, got her car fob and hit her panic button. Finally the noise and lights stopped. I guess my panic alarm set off the car alarm in my wife’s car. Stupid panic buttons. And that Myles, is why I was late getting back from lunch.
On days when nothing seems to be going right, it is nice when someone does some of your work for you. That’s what happened with this week’s story idea. We had an email into the store asking if we could do an article on domperidone. So here it is.
Domperidone is an interesting medication. It blocks the neurotransmitter dopamine. Neurotransmitters are chemical messengers in your brain. But domperidone doesn’t get into your brain. It can’t cross the blood brain barrier. It blocks dopamine from getting to another large clump of nerve cells in your body. This large clump of nerve cells is in your guts. There are so many nerve cells in your gut, it is sometimes called your gut brain. Some researchers say you have as many nerve cells in your gut as a cat has in its head.
When domperidone blocks dopamine in your gut it speeds things up. Food moves faster from your mouth to your stomach. This makes it useful to treat heart burn from acid reflux. If you give some one an acid blocker and domperidone that can be an effective way to stop the acid from splashing back up the esophagus.
I like to tell patients that domperidone helps everything in the gut move in a downward direction. So if someone has nausea, when we give domperidone before they eat, that can be help their nausea a lot.
In some conditions, the guts don’t move as well as they should. For example, some people with diabetes get diabetic gastroparesis. Their diabetes effects those gut brain nerves such that their guts don’t move their food and waste in a downward direction very well. Giving domperidone can help stimulate those damaged nerves and get the guts moving again.
Domperidone has off label uses too. One of the more unusual ones has to do with milk. Domperidone increases the hormone prolactin. As a useful side effect, this increase in prolactin means that domperidone can help increase the amount of milk a nursing mother produces when breast feeding.
The off-label use of domperidone for enhanced milk production brings up an interesting controversy. Domperidone is available inCanadabut not in theUS. That seems backward to many of us in pharmacy because new medications are often available first in theUSand can take years to be available here. Domperidone is an older medication, but you can’t find it on the shelves of aUSpharmacy. The Food and Drug Administration or FDA has banned domperidone in theUS. Among the reasons it has cited is the increased risk of heart problems with domperidone, especially in nursing mothers.
The FDA isn’t wrong about domperidone and heart problems. Domperidone can cause a specific type of heart problem call QT interval prolongation. But this side effect is quite rare and usually only happens if the person has a pre-existing heart condition, if they are on other medications that interact with the domperidone or they are on other medications that cause QT prolongation. In theUSthe closest alternative they have to domperidone is metoclopramide. Metoclopramide is available inCanadatoo and it can be used to treat nausea, diabetic gastroparesis, and it can be used off label to promote milk production. It also blocks dopamine receptors in the gut brain nerve cells. However, metoclopramide crosses the blood brain barrier. That means unlike domperidone, metoclopramide can cause sedation, dizziness and depression. Even more scary is that metoclopramide can cause movement disorders that make the person move as if they had Parkinson’s disease.
It’s not that we don’t use metoclopramide inCanada. We do and it is a very good drug that is very safe in most people. But when you look at the possible side effects, domperidone has many fewer side effects because it doesn’t cross the blood brain barrier. It seems odd that out of the two, the FDA has banned domperidone. It is kinda like the FDA didn’t know which of the two drugs it hit the panic button on.
The information in this article is intended as a helpful guide only. It is not intended to be used as a substitute for professional advice. If you have any questions about your medications and what is right for you see your doctor, pharmacist or other health care professional.
We now have this and most other articles published in the Parkland Shopper on our Website. Please visit us at www.dcp.ca
As always if you have any questions or concerns about these or other products, ask your pharmacist.
Food Scientist Heribert Watzke talks about “The brain in your gut”- www.ted.com/talks/heribert_watzke_the_brain_in_your_gut.html