Clinical chemotherapy Flashcards
What are the 4 different types of Chemotherapy-induced nausea and vomiting (CINV)
- Acute - patients experience n&v within 24hrs of chemo
- Delayed - patients experience n&v after 24hrs but within 2-5 days
- Anticipatory - conditional response that occurs after chemotherapy treatment. can be triggered by sight and smell
- Breakthrough - occurs despite prophylaxis treatment
What drugs can be used for CINV
- Ondansetron and Palonsetron
- Aprepitant
- Dexamethasone
- Metoclopramide
- Cyclizine
What is the MOA of Ondansetron and Palonsetron?
They are selective serotonin (5HT3) receptor antagonist
What is the MOA of Aprepitant
It is a neurokinin-1 (NK1) receptor antagonist and is a relatively new drug
What is the MOA of Dexamethasone
It is a corticosteroid that can be used for high risk acute or delayed CINV
What is the MOA of Metoclopramide
It is a D2 receptor antagonist and tends not to be used longer than 5 days because it prolongs the QT interval
What is the MOA of Cyclizine
It is a H1 receptor antagonist and has anti-muscarinic activity
What are the 2 pathways of CINV
-Peripheral pathway - it is primarily involved in the acute phase of CINV.
Chemoreceptors: (5HT3 and D2 in the GI tract) and liver are involved.
-Central pathway - it is predominantly involved in the delayed phase of CINV.
The receptors involved in the chemoreceptors trigger zone are D2, 5HT3, NK1
How can Dexamethasone be used for CINV?
For Acute CINV - use IV before chemotherapy
For delayed CINV - use orally for a few days after chemo
How is Ondasetron used for CINV?
- it can increase QT prolongation but that is dose-dependent
- smaller doses used if over 75 years old
Compare palonsetron to ondansetron
Palonsetron has a longer half life (40hrs) in comparison to Ondansetron (5hrs)
So if palonsetron is given in the acute phase of chemo then it is not required to take home
What is mucositis/stomatitis and drugs commonly cause it?
Inflammation and damage of the mucous membranes - lining of the mouth and other part of the GI tract.
The antimetabolite drugs such as 5-FU, Capcitabine, Methotrexate commonly cause it
How is mucositis/stomatitis managed
Oral hygiene advice:
- avoid spicy food
- use a soft toothbrush
- brush 2-3x a day
could use mouthwash such as chlorohexidine gluconate
What is Hand-foot syndrome (palmar plantar erythrodysesthesia) and drugs commonly cause it?
Patients hand and foot become red & sore then peels and ulcerate.
May require dose reduction or delay in chemotherapy in this case.
capecitabine is the most common cause of this.
How is Hand-foot syndrome (palmar plantar erythrodysesthesia) managed
Use moisturising cream for hand and feet so skin doesn’t dry out
Can use Udder cream that contains urea
How does Capcitabine cause Hand-foot syndrome
It is a pro-drug and the enzyme which breaks it down is found a lot in the hand and feet
What is the most common cause of chemotherapy-induced diarrhoea
Irinotecan (used to treat colorectal cancer) - its metabolite (SN38) causes diarrhoea
How do you treat diarrhoea WITHIN 24 hrs of having Irinotecan
Atrapine subcutaneous
How do you treat diarrhoea AFTER 24 hrs of having Irinotecan
High dose Loperamide
What can myleosuppresion lead to?
Anaemia - so fatigue
Neutropenia - so more likely to have an infection
Thrombocytopenia - so more likely to have a bleed
What is the common side effect of FEC-T
- Neutropenia
- Can give GCSF (Granulocyte colony-stimulating factor) which stimulates the bone marrow to produce granulocyte and bone marrow and release it into the blood.
What is neutropenic sepsis
a patient with low levels of neutrophils + an infection
it is a medical emergency that is a urgent referral.
How is neutropenic sepsis treated
Broad spectrum antibiotics
What is a common side effect with kinase inhibitors (-nib)?
Can develop an acne kind rash - more likely w/ EGFR inhibitors
Hair problems
- their hair becomes brittle and thin.
- eyelash becomes very long - common with EGFR inhibitors
What advice/ treatment can be given for the acne kind rash linked to kinase inhibitors
The patient can moisturise or topical antibiotics/steroids can be used
How does neuropathic pain occur in palliative care
the cancer tumour grows and pressed on nerves
What is the neuropathic pain ladder?
Step 1: TCA (e.g amitriptyline) or AC
Step 2: TCA (e.g amitriptyline) AND AC (e.g Gabapentin)
Step 3: TCA (e.g amitriptyline) AND alternative AC (e.g valproate)
Step 4: specialist use Ketamine or methadone
What is the MOA of amitriptyline for neuropathic pain and its side-effects
It prevents the re-uptake of noradrenaline or serotonin and takes 3-7 days to see the effect
Taken at night for neuropathic pain
side-effects: drowsiness and constipation
What are the side-effects of Gabapentin
Drowsiness and dizziness
it is an analogue of PABA and binds to site in the CNS
What classes of laxative are there?
Stimulant - e.g Senna
Softner - e.g docusate
Bulk formers - ispaghula husk
Osmotic - movicol, lactulose
How is breathlessness managed?
- oxygen prescribed for hypoxaemic patients ONLY
- low dose opioid could be used e.g morphine 1-2 mg
What are the causes of N&V
- chemotherapy
- biochemical imbalance
- fear and anxiety
- raised intracranial pressure
- muscle contraction
What is the most common adverse effect of DOXORUBICN (and other anthracyclines) and how is it managed?
- cardiotoxicity by generating OH radicals
- it is a dose limiting problem so there’s a max lifetime dosage (450mg/m2)
What is the most common adverse effect of Cyclophosphamide and how is it managed?
Haemorrhagic cystitis because of acrolin byproduct which is reactive and carcinogenic so causes damage to bladder
- Give mesna to react with acrolin
- aggressively hydrate
Why is FOLINIC ACID, Potassium chloride and sodium bicarbonate used after the treatment of methotrexate?
Potassium chloride and sodium bicarbonate;
-it ionises methotrexate which is acidic so methotrexate becomes more water soluble so can be excreted renally
FOLINIC ACID:
-Can form methyl donor and formyl donor w/out using dihdryfoloate reductase (DHFR) - the enzyme methotrexate inhibits. This means normal DNA can still be synthesised.
What are the 3 types of pain
Somatic pain - pains in the bone or muscle - deep, dull ache
Visceral pain - pain related to internal organs - can be throbbing/pressure pain
Neuropathic pain - pain in nerves - can be burning/stinging
What is the WHO analgesic pain ladder
Step 1 - Non-opioid - paracetamol
Step 2- weak opioid - 15-30mg codeine every 4 hrs PRN + adjuvant
Step 3 - strong opioid - morphine 10mg every 4 hrs PRN + non-opioid/adjuvant
How do you titrate a strong opioid from a weak opioid
- add up codeine dose used in last 24hrs then divide by 10
- divide the dose achieve by 2 to get the BD dose
- IR breakthrough opioid is 1/6 TDD
How do you titrate a patients dose who has not had a weak opioid
- titrate immediate release opioid 4hrly PRN
- so add up what the patient had in 24hrs then divide by 2 to get a MR opioid BD
- IR opioid PRN - 1/6th TDD
How is fentanyl used?
- used for stable pain
- can be used in renal impairment
- has a matrix and resvovoir patch.
- damage to resovioir patch can cause dose dumping
- the patch should be replaced every 72 hrs
- it should not be placed on hot skin as it can lead to over dose
What is the antiemetic treatment ladder
- Step 1: no antiemetics pre-chemo, metoclopramide take home
- Step 2: IV Dexamethasone pre chemo, Metcolopramide take home
- Step 3: IV Ondansetron/Dexamethasone pre-chemo, then Ondansetron/dexamethasone/metoclopramide take home
- Step 4: Same as step 3 with either Aprepitant in addition or Palonsetron instead of Ondansetron (IV/oral)
- Step 5: As step 4 with BOTH Aprepitant AND Palonsetron in place of Ondansetron (IV&oral)
What are the signs and symptoms of hypercalcemia and how is it managed
signs and symptoms:
- drowsiness/confusion/coma
- nausea/vomiting/constipation
- thirst/polyuria
Diagnosis:
blood test - ionised calcium levels or corrected calcium
Management:
- rehydrate
- bisphosphonate - given in severe cases eg Zoledronic acid IV - its potent and lasts a month
What are the signs and symptoms of superior vena cave obstruction (SVCO) and how is it managed
signs and symptoms:
- breathlessness
- swollen neck
- visible swollen veins
- oedema on the face, hand and neck
Management:
- stent to open up the vein
- high dose dexamethasone
- radiotherapy to the tumour
What are the signs and symptoms of spinal cord compression and how is it managed
signs and symptoms - can be non-specific:
- pins and needles in hand and feet
- paralysis of lower limbs
- urinary or faecal incontinence
Management:
- high dose dexamethasone for inflammation and oedema
- radiography
