Nausea and Vomiting

Appropriate assessment to identify cause and severity of symptoms

Explanation to patient and family at all stages

Correct reversible factors

Consider disease-specific palliative therapy

Institute non-pharmacological interventions

Prescribe appropriate first-line treatment

Consider adjuvant/second-line treatment

Review assessment and management regularly

Vomiting: Forceful expulsion of gastric contents through the mouth. 

Nausea: Unpleasant feeling of the need to vomit, often accompanied by autonomic symptoms e.g. pallor, cold, sweating, tachycardia and fear. 

Retching: Rhythmic, laboured spasmodic contractions of the diaphragm and abdominal muscles. It is essentially an effort to vomit that fails to expel gastric contents. Nausea is usually present and retching often ends in vomiting. 

40-60% of patients with advanced cancer suffer from nausea. Vomiting is present in 30% of these patients. 

Appropriate assessment to identify cause and severity of symptoms 

Assessment to identify probable cause and mechanism of nausea and vomiting (NB more than 1 may play a role) There are generally 3 pathophysiological mechanisms that cause nausea and vomiting: 

• Mechanical – gastric stasis, intestinal obstruction, excessive coughing, drug action on GIT, gastritis, ascites (increased intra-abdominal pressure), squashed stomach syndrome, Post surgery; eg. gastrectomy, resection of large tumour, constipation 
• “Toxic” mediated through chemo-emetic trigger zone – drugs, chemotherapy, infection, renal failure, hypercalcaemia, hyponatraemia, toxins from tumour breakdown. 
• Central mediated through vomiting centre- brain metastases and raised ICP, anxiety, pain, radiotherapy, vagal stimulation (mechano-receptors in GIT and chemo-receptors in GIT, sensory stimulus e.g. smell, sight 

An understanding of the emetic process and the main neurotransmitters involved is helpful in assessing and treating patients who are vomiting because anti-emetic drugs are predominantly neurotransmitter blocking agents. They are effective at different receptor sites and therefore treat different causes of vomiting. 

Vomiting is a complex reflex process. The vomiting centre lies in the medulla and has both histamine and muscarinic cholinergic receptors. 

• Stimulation of the vomiting centre occurs: 
• From the chemo-receptor trigger zone (CTZ) where dopamine receptors are concentrated
• From vagal afferents from the gastrointestinal tract
• From the vestibular centre. This, like the vomiting centre, contains both histamine and muscarine cholinergic receptors
• Directly, from raised intracranial pressure
• From psychological causes

Explanation to patient and family at all stages 

Nausea is an extremely distressing and debilitating symptom. The goal of treatment should be to control nausea. It may not be possible to eliminate vomiting, particularly in patients with malignant intestinal obstruction. Most patients will tolerate one or two episodes of vomiting when they understand the reason for this and when the symptom of nausea is controlled. Continuous nasogastric drainage is seldom necessary. Some colleagues are using intermittent nasogastric drainage under sedation using low doses of midazolam for unresponsive vomiting in bowel obstruction that is not considered for surgery. 

Correct reversible factors 

Consider surgery for intestinal obstruction, treat hypercalcaemia, drain ascites, stop unnecessary medications, antacids PPI (proton pump inhibitor) for gastritis, manage constipation 

Consider disease-specific palliative therapy 

• Surgery, chemotherapy, radiotherapy for cerebral tumour 
• Dexamethasone for raised intracranial pressure for inoperable cerebral tumour 

Institute non-pharmacological interventions 

• Adjust environment away from sight and smell of food/cooking 
• Avoidance of cooking smells and unpleasant odours 
• Arrange for someone else to prepare the food 
• Offer small portions 
• Cold food is often more palatable than hot food 
• Patient preference is more important than nutritionally correct diet 
• Positioning after meals (sit up ½ hour) 
• Eliminate odours from wounds through thorough wound care and other management e.g. antibiotic for infection, crushed metronidazole tablets applied to wound 
• Ensure good mouth care 

Prescribe appropriate first-line treatment 

Choose an anti-emetic based on the most likely cause of nausea and vomiting. If first choice drug is only partially successful after 24 hours, increase dose or use different anti-emetic 

Metoclopramide e.g. Maxolon 

Metoclopramide is useful for most causes of nausea and vomiting, except labyrinthine causes such as motion sickness. It is one of the most commonly used first-line anti-emetics in palliative care. It is particularly useful for mechanical causes of nausea and vomiting (except for complete intestinal obstruction) – metoclopramide 10 mg 6 hrly by mouth or 40-100mg/24 h by continuous subcutaneous infusion (CSCI). 

• Dopamine (D2) antagonist 
• Serotonin (5-HT3) antagonist in high doses 
• Serotonin (5-HT4) agonist in the gut, hence gastrokinetic effect 
• Extra pyramidal effects more common in young patients; Hyperprolactinaemia is possible 

Cyclizine e.g. Valoid 

Cyclizine is a useful first-line anti-emetic with a central action such as raised intracranial pressure and is used in managing the nausea of complete intestinal obstruction (vomiting will still occur) cyclizine 50 mg 8 hrly by mouth, 100 mg rectally 8 hrly 

• Histamine (H1) antagonist 
• Some anti-muscarinic activity 

Haloperidol: e.g. Serenace 

Haloperidol is particularly useful for drug-associated or metabolic nausea. Much lower doses are used to control nausea than in psychiatric practice haloperidol 1.5mg-5mg by mouth or by CSCI 

• Butrophenone neuroleptic 
• Dopamine (D2) antagonist 
• Sedating 
• Extra-pyramidal side-effects especially in patients who are HIV positive 
• Use with caution in epilepsy, liver disease, thyroid dysfunction 

Consider adjuvant/second-line treatment 

Anti-Emetics for specific syndrome 

If using more than one anti-emetic drug, metoclopramide can be combined with haloperidol. Cyclizine and haloperidol also form an effective combination. Cyclizine may antagonise the prokinectic effects of metoclopramide and they should not usually be administered together. Metaclopramide and hyoscine are also not a good combination. 

Vomiting is usually treated with oral drugs but in severe vomiting alternate methods will be used. An anti-emetic injection is suitable to control a single episode. Preferably anti-emetics are given as a suppository rectally or subcutaneously using a syringe driver. 

Indications for SC Infusions 

• Persistent nausea and vomiting refractory to tablets 
• Dysphagia 
• Intestinal obstruction 
• Semi-comatose or comatose states 
• Profound weakness 
• Poor absorption of drugs in the G-I tract 

Review assessment and management regularly 

At all stages of management consider: 

• Involvement of interdisciplinary team 
• Referral to appropriate service/more experienced clinician