Nausea/vomiting

Nausea and vomiting is a subjective sensation that can be very debilitating at the end of life.  The gastrointestinal tract or the brain (chemoreceptor trigger zone, vestibular apparatus, and cerebral cortex) are the primary organs involved with nausea and vomiting.   It occurs in 50-60% of patients with advanced cancer, and is more common in patients over 65 years of age, women, and those with stomach and breast cancer.

COMMON CAUSES
Nausea and vomiting is multi-causal and may be a component of cachexia syndrome.  The most common causes are the following:

  • medications  (i.e. opioids, chemotherapy, and anti-inflammatory drugs)
  • ulceration and gastritis
  • functional gastric stasis
  • constipation
  • gastroduodenal and intestinal obstructions
  • metastases to the brain or liver
  • mucosal irritation
  • motility
  • biochemical causes (hypercalcemia, liver or kidney failure, infection, tumour toxins);
  • increased intracranial pressure
  • anxiety
  • unrelated condition (i.e. gall bladder disease, gastroenteritis)

ASSESSMENT
Identification of the pathophysiologic origin of nausea and vomiting is helpful in deciding what intervention to use.  In most cases the causes of vomiting and nausea is multi-factorial and a careful history and clinical examination can help to determine the causes.  Information regarding the volume, content, and timing of vomits is useful.  In some cases a biochemical profile is ordered, but other investigations are generally not necessary.

MANAGEMENT

Non-Pharmacological Interventions
Patients should be encouraged to try eating small light meals throughout the day, which include bland, soft and easy-to-digest foods.

Relaxation and cognitive therapy such as mental imagery can be used to control the cortical causes of nausea and vomiting and studies have shown that it can also be effective for patients receiving chemotherapy.

TENS and acupuncture have also been used to control nausea and vomiting and can add to the effects of anti-emetic drugs.

Pharmacological Interventions

Dopamine antagonists
Dopamine-mediated nausea is the most common form of nausea and, therefore, antidopaminergic drugs should be used first when cause of nausea is not clear.

The dose should be optimized in this situation before changing to or adding another drug.

Different drugs in this class work at different areas: haldol works at the chemoreceptor trigger zone (CTZ), metoclopromide and domperidone work at the gut by stimulating anticholinergic activity, increasing peristalsis and decreasing gastroparesis

Side effects include: hypotension, drowsiness and extrapyramidal effects (incidence is low if use domperidone)

Dose of metoclopramide must be reduced in renal failure.

Histamine antagonists (antihistamines)
Histamine antagonists act on H1 receptors in the vomiting centre and on vestibular afferents. They also have anticholinergic effects.

Side effects include: sedation and hypotension, dry mouth, blurred vision.

Acetylcholine antagonists (anticholinergics)
Anticholinergics can be particularly useful if nausea and/or vomiting is triggered by opioids and anesthetics which act by triggering acetylcholine receptors in the vestibular apparatus.
 
They are also useful if nausea and vomiting is caused by partial or complete bowel obstruction since it decreases peristalsis, resulting in a decrease in colic and decreased secretions.

Side effects of anticholinergics include: drowsiness; dry mouth; dry secretions; blurred vision; ileus and urinary retention.

Serotonin antagonists
Serotonin has been particularly implicated in chemotherapy-associated nausea. 5HT3 receptors are located in vomiting center chemoreceptor trigger zone (VC CTZ) and in the vagal nerves and enterochromaffin cells of the gut wall.
 
These are very expensive so typically used in chemotherapy and radiation associated nausea or if other medications have failed.
 
Can be useful for refractory nausea of diverse types but are typically tried only when other medications have failed.

Prokinetic agents
Altered peristalsis can be an important cause of nausea and vomiting in advanced disease or may be seen as side effects or drugs used to palliate other symptoms, such as opioids. 

Antacids/ Cytoprotective agents
Hyperacidity, gastroesophageal reflux and/or gastric or duodenal erosions, may also cause nausea and vomiting.
 
Consider using an antacid, or H2 receptor blockers or proton pump inhibitors such as ranitidine, famotidine, and omeprazole.

Other medications
Other medications do not have a mechanism of action that can be clearly defined.

These include:

Steroids: Dexamethasone. Thought to have intrinsic antiemetic properties and may increase the effects of other drugs.

Cannabinoids: Tetrahydrocannabinol. Marijuana may be more effective than synthetic analogues, but psychomimetic effects, especially dysphoria, in elderly, often limit its use and low doses of phenothiazines can help.

Benzodiazepines: Lorazepam. These drugs do not have any antiemetic properties but may reduce anticipatory nausea.

You must login to your Care Journal to bookmark pages.

This page was last updated: March 8th, 2005 at 5:39pm.