October 7, 2011

Chemo = Vom

Looking at or smelling chemotherapy drugs don't make you feel sick; they have to be inside the body to cause nausea and vomiting. And this doesn't involve the stomach (well, not at first, the vomiting bit is all stomach), it involves the small intestine.

Because cells lining the small intestine are particularly sensitive to chemotherapy drugs.

When these cells are damaged by chemotherapy drugs, they release the neurotransmitter serotonin. The name serotonin is loaded with meanings related to happiness in people and bullying in male animals, but around 90% of serotonin in the human body is found in cells lining the gut, where it has the mundane job of regulating how fast the digestive system pushes food along.

Three roads lead to vomit town.

The main road

Serotonin released by intestinal cells damaged by chemotherapy drugs is detected by vagal nerves hanging out near these cells. Vagal nerves send information (WARNING: Gut has been poisoned) to the medulla oblogata, the region of the brain where the Vomiting Centre is located. Then you feel sick and vomit.

The small side road

Serotonin released by upset intestinal cells enters the blood stream, chemoreceptor trigger zones detect it and alert the Vomiting Centre that something isn't right (WARNING: High levels of serotonin in blood stream mean gut is poisoned). Then you feel sick and vomit.

The smaller side road

The chemo itself is directly detected by the chemoreceptor trigger zones that alert the Vomiting Centre (WARNING: Poison in blood stream). Then you feel sick and vomit.

Controlling the flow

Oxaliplatin is a non-targeted chemotherapy drug and a part of my treatment. It is especially emetic, meaning it causes nausea and vomiting (emesis) in nearly everyone that has it. It even causes nausea and vomiting when given to patients in combination with super duper drugs that stop nausea and vomiting.

Drugs that try and stop nausea and vomiting act as road blocks along the streets that lead to vomit town. I'm a particular fan of one of these drugs, a steroid, because I now put on one kilogram of weight a week, have bouts of anxiety, and suffer from insomnia.

I refer to these side effects collectively as Roid Rage.


  1. Poor Ben...Vomiting sucks. When will you be off chemo?


  2. This is extremely informative Ben-o - especially serotonin's moonlighting gig as gut protector, but why is roid rage man sporting a milk moustache? Fascinating. Pipxx

  3. Jian - I have not vomited once while on chemo. The anti-nausea works fine on me.