Nausea Flashcards
Causes of nausea at EOL
GI Factors:
- Pharyngeal Irritation (Oral/esophageal candidiasis, tenacious sputum/persistent cough)
- Gastric irritation (PUD, gastritis)
- Gastric stasis (Opioids or anticholinergics, hepatomegaly or GOO)
- Stretching or distortion of the GI tract (Constipation, intestinal obstruction, mesenteric mets)
- Infections of the GI tract (fungal, bacterial, parasitic infections - particularly in HIV/AIDS)
Meds:
- Opioids, particularly intro or increase
- Cytotoxic drugs
- SSRIs
- Antivirals or Antibiotics
Metabolic
- Hypercalcemia
- Renal failure
- Liver failure
- DM
- Cytokine or other tumour factors
Cranial
- Raised ICP secondary to brain mets or leptomeningeal involvement, post-rads
- CNS infections (AIDS)
Psychosomatic
- Anxiety, pain, anticipator nausea
Pathophysiology of emesis - Chemoreceptor Trigger Zone
Chemoreceptor Trigger Zone (area postrema in fourth ventricle)
- No blood brain barrier - Bathed in CSF with chemoreceptors (D2, serotonin, and cannabinoid) responsive to drugs and electrolytes - Relays neurotransmitters to Vomiting Centre and vomiting reflex
Pathophysiology of Emesis - Vomiting Centre
Vomiting Centre is a diffuse network in the medulla oblongata of the mid brainstem
- Nausea without vomiting may be due to stimulation of the VC without enough amplification to trigger the vomiting cascade - H1, acetylcholine, serotonin receptors - Input from the CTZ, vestibular apparatus and cerebellum, higher cortex, gut chemoreceptors and mechanoreceptors, mechanoreceptors in viscera/serosa (head and neck, thorax, abdomen, pelvis) - Stimulation causes parasympathetic and sympathetic output as well as neurotransmitter cascade to induce vomiting
Inputs to Vomiting Centre
CTZ (area postrema in fourth ventricle)
- D2, serotonin 5-HT3, opioid receptors, acetylcholine receptors, substance P reeptors
Vestibular system (via CN 8 - vestibulocochlear), motion sickness - muscarinic and H1 receptors
CN X (vagal nerve) - pharyngeal irritation (gag reflex)
Vagal and enteric nervous system (chemoreceptors, mechanoreceptors in gut, mechanoreceptors from viscera/serosa), D2 and Serotonin
CNS (psychiatric disorders, stress), H1 receptor
Approach to Nausea/Vomiting
- Identify likely cause(s) and evaluate for dehydration, potential for opioid neurotoxicity
- Identify pathway by which each case triggers vomiting reflex
- Identify neurotransmitter pathway
- Choose most potent antagonist to the receptor identified (dictated by binding affinity)
- Choose route (often not oral as patients may not be able to tolerate)
- Titrate carefully
- Give regularly
- If symptoms persist - review likely cause and consider overlooked causes or other contributing causes
- Consider combining antiemetics, but be mindful of interactions (antihistamines and anticholinergics may counteract prokinetics!)
Rx for Opioid nausea, neurotransmitter and site
- CTZ
- D2 receptor
- Haldol 1.5 - 5mg q8-12h, PO or SC (first line)
- Levomepromazine 5 - 12.5mg q daily, PO or SC
- Prochlorperazine 5-10mg (PO, SC, IV) BID-QID
Rx for Gastric stasis, Ileus, neurotransmitter and site
- Gastroinstestinal site
- Serotonin (to a lesser extent, dopamine, histamine, Ach)
- Prokinetics preferred
- Domperidone 10-20mg PO q4-8H AC meals
- Metaclopramide - 10-20 mg PO/SC/IV TID AC meals
Rx for Gastric Obstruction, neurotransmitter and site
- Gastroinstestinal site
- Serotonin (to a lesser extent, dopamine, histamine, Ach)
- Phenothiazines, antihistamines, anticholinergics
- Levomepromazine 5-12.5mg/24hr PO/SC
- Cyclizine 25-50mg PO/SC/PR q8h
- Scopolamine 20mg PO/SC q6h (especially if colicky)
- Dex 8mg qAM to try to relieve obstruction (trial for 4-5 days)
Rx for Chemotherapy nausea, neurotransmitter and site
**Check guidelines from ASCO for this
- CTZ (area postrema in fourth ventricle) and gastrointestinal site
- CTZ = dopamine, GI site = serotonin (to a lesser extent for both, Ach and histamine)
- 5-HT3 antagonists, NK1 antagonist, prokinetics
- Ondansetron 8mg PO/SC (consider addition of Dex to enhance efficacy)
- Aprepitant 125mg PO 1hr prior to chemo, then 80mg OD for the next two days
- Metoclopramide 10-20mg PO/SC q4h
Also consider haldol, and olanzapine 5-10mg q daily on days before and during chemo has been found to be effective, though evidence may be poor.
Rx for raised ICP nausea, neurotransmitter and site
- Cerebral Cortex
- GABA, Histamine
-Use Phenothiazines (prochlorperazine 5-10mg/12.5-25m IM q8H) along with Dex for decreasing ICP
Maxeran for Nausea (indications, dose, side effects, notes)
Metoclopramide 10-20mg PO/SC/IV q4H
CTZ and GI tract, D2. Note that metoclopramide potentiates 5-HT3 receptors (may be used with ondansetron, but watch QT) and can act on 5-HT3 at higher doses. Central antiemetic effect plus prokinetic effect and decreased pylorus activity - food passes through more quickly.
Indications: Gastric stasis, ileus (avoid in complete obstruction), may use for Chemotherapy
Do not combine with anticholinergics (scopolamine, hyoscine, diphenhydramine) due to counteracting effects. Note that olanzapine, levomepromazine also have anticholingeric effects and increase risk of EPS.
Side effects: EPS, restlessness, drowsiness, colic in GI obstruction. Risk of tardive dyskinesia, especially if used longer than 12 weeks, at higher doses, or in patients under 20 years old. Risk increased with combination with antipsychotics!
Prolonged half life in renal failure, long QTc. Caution in Parkison’s (may worsen symptoms as a dopamine antagonist)
EPS with anti-nauseants - symptoms, pathophys, agents
Symptoms: Parkinsonism, dystonia, tardive dyskinesia, akathisia
Seen with Maxeran and prochlorperazine overdose (usually but not always reversible)
Levomepromazine for nausea (indications, dose, side effects, notes)
5-12mg PO/SC over 24 hrs (BID or continuous SC infusion)
Receptors: D2, 5HT2, H1, acting on VC
Indications: Intestinal obstruction, peritoneal irritation, vestibular, raised ICP, unknown causes
Side effects: Long QTc, sedating, orthostasis, anticholinergic effects (esp in elderly) - confusion, hallucinations, EPS
Non-pharm measures for nausea
Citrus Ginger Peppermint Cold, lightly carbonated beverages Hydration Decrease odours
Glucocorticoids for nausea (indications, dose, side effects, notes)
Exact mechanism unknown, likely glucocorticoid receptors in central nucleus.
Dexamethasone 4-8 mg PO qAm (higher doses if related to increased ICP)
Side effects: Hyperglycemia, Cushing syndrome, weight gain, PUD, infection, aseptic necrosis (femoral/humerol heads), impaired wound healing, steroid psychosis, adrenal suppression,
Pearls:
- Antiemetics are better at vomiting control than nausea, but a higher dose may control nausesa better
- Initially, use a single drug to maximum tolerated dose
- Broader spectrum drugs (methotrimeprazine, olanzapine) may be as effective as multiple simultaneous antiemetics
- Oral administration is preferred, but consider parenteral if the patient has vomiting, malabsorption, or stasis. After 3 days, consider converting to PO administration except in cases of mechanical obstruction
Combinations to avoid
Prokinetics (maxeran) and anticholinergics (dimenhydrinate, scopolamine) as combination is illogical
Maxeran with antipsychotics (increased risk of EPS)
Cannabis for nausea - evidence
No controlled clinical efficacy studies
Nabilone
Antiemetic alternative
Nabilone 0.25 - 2mg PO BID (start low)
Acts on cannabinoid receptors (CB1) in CNS
Side effects: Drowsiness, dizziness, vertigo, euophoria, ataxia, xerosteomia
Approach to opioid nausea
- Antiemetics may be helpful, but no clear evidence for a preferred antiemetic choice
- Switching opioids or route may help.
- Note that most patients develop tolerance to the emetic effect of opioids after 5-7 days, and so anti-nauseants after that point can be PRN (or a half hour prior to meals if connected with eating)
Epidemiology of Nausea and Vomiting (cancer)
Occurs in 50-70% of patients with advanced cancer
Epidemiology of Nausea and Vomiting (AIDS)
43 - 49% of patients with AIDS
Epidemiology of Nausea and Vomiting (ESRD)
30 - 43% ESRD
Epidemiology of Nausea and Vomiting (Advanced cardiac disease)
17 - 48% Advanced Cardiac Disease
Epidemiology of Nausea and Vomiting (Multiple Sclerosis)
26% in MS
Antihistamines for vomiting - examples, receptors, site of effect, and side effects
- Dimenhydrinate 50-100mg PO/subcut q6h PRN, cyclizine 25-50mg PO/SC/PR q8H
- H1
- Works at CTZ, GIT, CNS, VC, Vestibular nuclei
- Useful for motion sickness
- Side effects: Sedation, constipation (often avoided for these reasons)
Anticholinergics for vomiting - examples, receptors, site of effect, and side effects
- Scopoloamine 20mg PO/SC q6h
- Targets ACh
- Works at VC, GIT
- Useful for intestinal obstruction, peritoneal irritation, raised ICP, excess secretions
- Side effects: Dry mouth, sedation, ileus, urinary retention, blurred vision, occasionally agitation
- Useful if NV coexist with colic, illogical to give with prokinetics
Phenothiazines for Nausea/vomiting - examples, receptors, site of effect, and side effects
- Prochlorperazine 5-10mg PO, 12.5-25mg IM q4-6H regular, q1H PRN
- Methotrimeprazine (Nozinan) 6.25-12.5mg PO/SC q6H reg, PRN
- Targets D2, H1, 5HT3, ACh (Prochlorperazine only for ACh)
- Works at CTZ, GIT, VC, CNS (but NOT vestibular nuclei)
- Useful for intestinal obstruction, peritoneal irritation, nausea of unknown etiology, vestibular causes, raised ICP
- Side effects include drowsiness, orthostatic hypotension
- Prochlorperazine can cause EPS (less likely with Nozinan)
Serotonin antagonists for nausea/vomiting - examples, receptors, site of effect, and side effects
- Ondansetron 8mg PO/SC/IV q8H
- Targets 5HT3
- Works at GIT, CTZ
- Useful for chemotherapy, abdominal radiotherapy, post op NV
- Side effects: Constipation
- Note - expensive
Butyrophenones for nausea/vomiting - examples, receptors, site of effect, and side effects
- Haldol 1.5-5.0mg/day PO or SC in two divided doses, plus hourly PRN
- Targets D2
- Works at CTZ
- Useful for opioid-related nausea, chemical or metabolic nausea
- Side effects: EPS (at higher doses) QTc, somnolence. Side effects unusual at lower doses
- Caution with liver impairment
Cannabinoids for nausea/vomiting - examples, receptors, site of effect, and side effects
- Nabilone 1-2mg PO BID
- CB1 receptor
- Works at CNS, GIT (decreases intestinal motility)
- Side effects: Euphoria, dysphoria, anxiety, mania, tachycardia, dry mouth, appetite stimulation, later drowsiness
- Use with caution, not first line
Prokinetics for Nausea/vomiting - examples, receptors, site of effect, and side effects
- Maxeran 10mg PO/SC/IV q4-8H
- Domperidone 10-20mg PO/q4-8H – cannot be given parentally
- Targets D2 (Maxeran targets 5HT4 at higher doses)
- Works at GIT, CTZ
- Useful for gastric stasis or ileus
- Side effects: Colic if obstruction, long QTc, EPS (maxeran, note Domperidone does not cause BBB
Anxiolytics for nausea/vomiting - examples, receptors, site of effect, and side effects
- Lorazepam 1mg PO/SL
- Works at CNS
- Useful for anticipatory nausea/vomiting
- Side effects: Drowsiness, lethargy, confusion – caution when combining with opioids
Dexamethasone for nausea/vomiting - examples, receptors, site of effect, and side effects
- Dexamethasone 4mg PO qDaily
- Mechanism of action not well understood, works well with Aprepitant or Ondansetron with highly emetogenic chemo
- Side effects: Confusion, euphoria, insomnia, psychosis, fluid retention, gastric irritation, hyperglycemia, osteoporosis, osteonecrosis (long term)
NK1 antagonists for nausea/vomiting, examples, receptors, site of effect, and side effects
- Aprepitant 125mg PO prior to chemo, 80mg per day there after for two days
- NK1, wide spread site of activity
- Used for late onset chemotherapy NV
- Side effects: hiccups, asthenia, fatigue, anxiety, somnolence