Palliative Care: Nausea And Vomiting Flashcards
N&V is the …..most troublesome symptom for cancer patients
Second
Occurs in up to 70% with advanced disease
What percentage does it affect with non malignant end stage disease?
Up to 50%
Is it true that vomiting even daily, without nausea is usually better tolerated?
Yes
Nausea and vomiting in palliative care is often multi-factorial, but which are most common?
Gastric stasis
Chemical disturbance
What causes are there?
Infection Metabolic Gastric stasis GI disturbance Neurological Psychological Drug related Organ damage
What infections can cause N&V?
Gastroenteritis Thrush Pneumonia UTI Viral labyrinthitis
What metabolic disturbances can cause N&V?
Renal impairment Hepatic impairment Hyponatraemia Hypercalcaemia Sepsis Hyperglycaemia
What drugs can cause nausea and vomiting?
Opioids Chemotherapy RT Antibiotics NSAIDS Diuretics Digoxin SSRIs
What can cause gastric stasis?
Pyloric tumour/nodes Ascites Hepatomegaly Opioids Anticholinergics
What GI disturbances can cause N&V?
Constipation
Gastritis
Ulceration
Obstruction
What neurological factors can cause N&V?
Raised ICP (usually in context of cerebral mets)
Motion sickness
Meningeal disease
Vestibular - related to activation of acetylcholine and histamine (H1) receptors
What psychological factors can cause N&V?
Anxiety
Fear
Pain
Anticipatory nausea
What percentage will have more than 1 cause ?
25%
How is choice of anti emetic decided upon?
The probable cause and the mechanism by which the drug acts
What neurotransmitters are implicated in the control of nausea and vomiting?
Acetylcholine (AChm receptor) Dopamine (D2 receptor) Histamine (H1 receptor) Substance P (NK-1 receptor) Serotonin (5HT3 or 2 receptors)
What can vomiting also be referred to as?
Emesis
What symptoms are associated with emesis?
Profuse salivation Sweating Tachycardia Pallor Nausea Retching movements
How are the contents of the stomach expelled?
The stomach, oesophagus and their sphincters are relaxed during vomiting. Most of the expulsion force arises from the contraction of the diaphragm and the abdominal muscles .
Where is the chemoreceptor trigger zone located in the brain?
Medulla - specifically the area postrema (on the floor of the fourth ventricle)
Is the CTZ in or outside the BBB?
Outside - so emetic toxins in blood can reach it
What is the role of the chemoreceptor trigger zone?
Respond to various stimuli - toxins and drugs in the blood
Communicate with the vomiting centre, which initiates emesis
Where is the vomiting centre found?
Within medulla (has a BBB)
Which cancer chemotherapy agents are highly emetic?
Cisplatin
Cyclophosphamide
Adriamycin
What receptors are located at the CTZ?
D2
NK1
5HT3
What receptors are located at the vomiting centre?
AChm
H1
5HT2
NK1
Also mu receptors
How does CNVIII interact?
It has AChm and H1 receptors
Communicates with CTZ and vomiting centre
How does Haloperidol work?
A potent D2 antagonist
Widely used in context of chemical causes of nausea and vomiting
What are the features of chemical associate nausea and vomiting?
Persistent, often severe nausea
Unrelieved by vomiting
Aggravated by sight/smell of food, drowsiness/ confusion
What anti emetics are best for chemical causes?
Haloperidol
Metoclopramide
Ondansetron
Metaclopramide acts on what receptors?
D2 and 5HT3
Helps in those with delayed stomach emptying and GORD
What anti emetics are best for gastric stasis?
Pro kinetics
- they are often D2 antagonists
E.g metaclopramide or domperidone
Domperidone acts at what receptor ?
D2
What are the features of gastric status nausea and vomiting?
Fullness and regurgitation Reduced appetite Vomiting large volumes relives nausea Epigastric discomfort Hiccups
How does cyclizine work?
H1 antagonist
ACh antagonist
What antiemetics are good for bowel obstruction?
Cyclizine - slows peristalsis
Dexamethasone - reduces oedema
What does NICE suggest to use for raised intracranial pressure induced N&V?
Cyclizine
Dexamethasone also used
What features are associated with raised ICP associated N&V?
Nausea worse in morning
Projectile vomiting
Worse on head movement
Headache
What anti emetic is best for vestibular causes?
Cyclizine
Refractory cases: prochlorperazine
What can be used if anticipatory nausea is the clear cause?
Short acting benzodiazepine e.g lorazepam
If benzodiazepines not ideal - cyclizine
What is Aprepitant?
An anti emetic that works by blocking substance P from acting at NK1 receptors
Acts mainly centrally
What is aprepitant used for?
Emetogenic chemotherapy
What is frequently cited as the most distressing side effects of chemotherapy?
Nausea and vomiting
CINV has increased risk associated with what?
Specific chemo agents
Female gender
Age less than 50
Past history of nausea and vomiting - pregnancy, motion sickness, prior chemotherapy use
What types of CINV are there?
Acute
Delayed
Anticipatory
What side effects of aprepitant are there?
Constipation
Headache
CINV consists of an acute and delayed phase. Acute phases emesis responds well to …
5HT3 antagonists e.g ondansetron
Delayed phase remains difficult to control (but the discovery of NK1 antagonists helped as they elicit anti emetic effects in acute and delayed)
When is ondansetron used?
Chemotherapy, radiotherapy or surgery
No effect on vomiting caused by motion sickness
Only 5HT3 effect
How does hyoscine work?
Anticholinergic
Very sedating
When is hyoscine used?
Motion sickness
Post op nausea and vomiting
May be used pre surgery to reduce saliva
Bowel obstruction
Control of symptoms using one anti emetic is possible in what percentage of patients?
60%
1/3 required second antiemetic - combine antiemetics with different mechanisms of action
What route is generally preferred?
Oral absorption likely to be poor, so consider SC for at least 24 hours
Switch to oral if improving
What non pharmacological measures can be tried?
Smells that patient likes
Small, appropriate meals
Acupuncture ?
What is levomepromazine typically used for?
Low potency antipsychotic
Analgesic, antiemetic and hypnotic properties
Primarily used in palliative care
“Dirty drug” - blocks a variety of receptors: D2, 5HT2, H1, ACH
Why is dexamethasone useful?
Reduces permeability of BBB to emetogenic substances
Improves effects of other anti emetics including NK1 antagonists, 5HT3 and metaclopramide
Why are seratonin antagonists useful in CINV?
Following chemotherapy there is a huge release of serotonin from enterochromaffin cells in bowel wall
What would be the first choice in pregnancy associated nausea and vomiting?
Cyclizine - greater experience with them and not thought to be teratogenic
What are the side effects of cyclizine?
Sedation
Dry mouth, blurry vision, urinary retention
