Nausea and Vomiting Management Flashcards
What is nausea?
Nausea is an unpleasant feeling of the need to vomit associated with autonomic symptoms (pallor, sweating, tachycardia, salivation)
What is vomiting?
The forceful propulsion of gastric contents through the mouth
What should you ask about in the history for a cancer patient with nausea and vomiting?
When did it start? Has it been constant or improved? What did it look like? Was there any blood in the vomit? How did it start? Has this happened before? how has it been treated if it has happened before Has anything helped to make it better or worse
How should you manage a patient complaining of nausea and vomiting?
Identify and correct any reversible causes- e.g. hypercalcemia, uraemia, GI infection
Non-pharmacological methods- avoid triggers, small frequent meals, ginger, mint
Pharmacological- Prescribe an anti-emetic
Correct any prescribing issues- PO route may no longer be suitable. Identify possible drug causes.
What are syringe drivers?
Syringe drivers are used for continuous subcutaneous infusions of drugs. This therefore gives continuous delivery via an alternative route to PO. They allow for rapid control of symptoms and easy dose adjustments by adjusting the drive rate.
What are some commonly used antiemetics?
Metoclopramide Cyclizine Haloperidol Ondansetron Levomepromazine
What are the symptoms of gastric stasis?
Feeling of epigastric fullness Early satiety Large volume vomits Hiccups Regurgitation Nausea quickly relieved by vomiting
What causes gastric stasis?
Drug side effects- anticholinergics, opioids
Gastric outflow obstruction- tumour, hepatomegaly, ascites
Gastritis
How should gastric stasis be managed?
Reduce intake to little and often
Reduce gastric secretions- PPI or H2 antagonist (Ranitidine)
Prokinetic agent: Dopamine Antagonists e.g. Metoclopramide, Domperidone
What is metoclopramide, how does it work?
Metoclopramide is an antiemetic that works as a prokinetic agent.
It is a D2 receptor antagonist and 5-HT4 agonist
Metoclopramide crosses the blood brain barrier so can worsen parkinson’s and cause EPSEs
What is the usual dose of metoclopramide?
10mg TDS PO
What are some side effects of metoclopramide?
Metoclopramide crosses the blood brain barrier. It can therefore cause EPSEs and worsen parkinson’s disease.
Caution in younger patients as there is a risk of oculogyric crisis.
What is an alternative to metoclopramide that does not cross the blood brain barrier?
Domperidone- this should be used in patients with parkinson’s or who develop EPSEs
Why does chemotherapy cause nausea and vomiting?
Chemotherapy targets cells with a rapid turnover, such as the GI mucosa. This is reduced when chemotherapy is taken and so there is irritation of the GI tract which causes nausea and vomiting.
What agent should be used to treat chemotherapy related nausea?
Ondansetron should be used
How does ondansetron work?
Ondansetron is a 5-HT3 antagonist
When should ondansetron be used?
Post chemotherapy
Post radiotherapy
Post surgery
What are two side effects of ondansetron?
1) Causes constipation- give laxative too
2) QT prolongation
How does cyclizine work?
It is a centrally acting anti-muscarinic and antihistamine
When is cyclizine used?
It is a good first line antiemetic in hospital
Useful for motion sickness and vomiting secondary to raised ICP
What is the dose of cyclizine?
50mg TDS IV/PO/SC
What are some side effects of cyclizine?
Antimuscarinic- dry mouth, constipation
Antihistamine- sedation
What condition should cyclizine be avoided in?
Heart failure
Why should cyclizine and metoclopramide not be prescribed together?
Metoclopramide is a pro-kinetic that treats gastric stasis, due to D2 antagonism.
Cyclizine slows gastric transit due to its antimuscarinic effect.
Therefore block the effects of each other.
What are some metabolic causes of nausea and vomiting?
Renal failure- Uraemia Liver failure Hypercalcaemia Hyponatremia Sepsis
What drugs should be used to treat chemical or metabolic nausea and vomiting, due to stimulation of the CTZ?
Stimulation of the chemoreceptor trigger zone involves D2 receptors and 5HT receptors. Treatment for chemical (drugs) or metabolic nausea and vomiting therefore involves:
Haloperidol- D2 antagonist
Levomepromazine- Multiple receptors
Ondansetron- 5- HT3 Antagonist
When should haloperidol be used for N+V?
If it is thought to be due to drugs or metabolic stimulation of the CTZ.
How does haloperidol reduce N+V?
Haloperidol is a D2 receptor antagonist. This prevents stimulation of D2 receptors at the CTZ.
What is the dose of haloperidol for antiemetic action?
1.5mg-3mg SC/PO
What are some side effects of haloperidol?
EPSEs- due to dopamine blockade
Sedation
QT prolongation
When is levomepromazine used?
Used commonly in palliative care, use for drug or metabolic induced nausea
These cause stimulation of the CTZ via D2 and 5HT receptors
What are some side effects of levomepromazine?
Sedation
Postural hypotension
What are some symptoms of raised ICP?
Headache Nausea and vomiting Worse when coughing/sneezing or bending forward Worse when lying down Classically a morning headache Papilloedema
What agent might be used to treat nausea and vomiting due to raised ICP?
Cyclizine- antimuscarinic and antihistamine activity
Treat the cause of raised ICP- e.g. high dose steroids if brain mets
What antiemetic is recommded for treatment of motion sickness?
Cyclizine
Why should metoclopramide not be combined with ondansetron?
Risk of serious cardiac arrhythmia
How does metoclopramide work?
D2 antagonists- passes through BBB so can cause EPSEs
How does cyclizine work?
Antihistamine and antimuscarinic
How does haloperidol work?
D2 antagonism
How does ondansetron work?
5-HT3 antagonist
How does levomepromazine work?
Lots of receptors are targeted
What are some causes of constipation?
Drugs- opiates, ondansetron, anticholinergics, diuretics
Diet- low fibre, poor fluid intake
Reduced activity- sedentary lifestyle, inability to get to the toilet
Electrolyte imbalance- hypercalcaemia, hypokalemia
Bowel obstruction- malignancy, strictures, scarring, adhesions
Hypothyroidism
Neurological conditions- spinal cord compression, GBS
What should you ask about in the history for a patient with constipation?
When did you last open your bowel? What is normal for you? Are you passing any air? It not this is total obstruction What are their stools like? Hard, softt Recent drug changes?
Do a PR.
What are some basic rules for managing constipation?
If stool is hard- needs a softener
If stool is soft- needs a stimulant
How do stimulant laxatives work?
This increase the amount of peristalsis
Give an example of a stimulant laxative
Senna
Bisacodyl
Danthron- used only in terminal care as carcinogenic
What type of laxative should be used in opioid induced constipation?
Stimulant laxative e.g. Senna
When are stimulant laxatives contraindicated?
Stimulant laxatives are contraindicated if there is bowel obstruction as they could cause bowel perforation.
When should stool softeners be used?
If patients are constipated with hard stools
Give an example of a stool softener
Docusate sodium
Osmotic laxatives- Lactulose/ Movicol
How do osmotic laxatives work?
They draw fluid into the bowel, patients therefore require a good fluid intake
What suppositories may be used to treat constipation?
Bisacodyl- causes anorectal stimulation
Glycerol- draws fluid into the rectum to soften and lubricate the stool
These are often required by patients on high dose opiates
What is likely to cause bowel obstruction in palliative care patients?
GI malignancy causing obstruction
External compression with gynaecological malignancy
This is called malignant bowel obstruction
What indicates true obstruction rather than constipation?
Failure to pass any gas
What are the features of bowel obstruction?
Constipation
Distension
Colicky abdominal pain
Failure to pass any gas
If the patient does not have colicky pain and bowel sounds are absent what does this suggest?
This suggests that there is a paralytic component- the bowel is not contracting. This is an ileus.
How should malignant bowel obstruction be managed?
If possible relieve the obstruction. This is done surgically with tumour resection or bowel stenting.
Medical management-
Steroids can reduce oedema around tumours and relieve obstruction
Reduce colicky pain with opiates and antispasmodics such as buscopan
Antiemetics
Antimuscarinics to reduce secretions?
Keep hydrated
How should antiemetics be given in malignant bowel obstruction?
Any medications can no longer be given PO.
Syringe driver for continuous subcutaneous infusion.
If no colic, paralytic ileus- Prokinetic such as metoclopramide (D2 antagonist)
If colic- cyclizine, haloperidol, levomepromazine
What agents can be given to reduce secretions in malignant bowel obstruction?
Buscopan is antispasmodic and anti secretory due to its actions on anti-muscarinic receptors.
Buscopan is hyoscine butylbromide
How does buscopan help in malignant bowel obstruction?
It is antimuscarinic and antispasmodic
Therefore reduces secretions and smooth muscle contraction
What are some side effects of buscopan?
Dry mouth
Constipation
How should buscopan be given for malignant bowel obstruction?
Subcutaneously
What is octreotide?
This is another anti-secretory
It works quicker than buscopan and is given by syringe driver or BD SC injection
It is more expensive than buscopan
What is important to consider at the mouth for patients with malignant bowel obstruction?
Patients are prone to developing a dry mouth and this can be very uncomfortable. Ice chips can help with this. Pineapple juice also helps.
