Chemoreceptor trigger zone situated where
postrema on the floor of 4th ventricle
Vomiting centre situated where
Close to CTZ, in medulla
With regards to BBB where are CTZ/ vomiting centre are
Inside BBB ; VOMITING CENTRE
Outside BBB: CTZ
Vomiting centre role
Collection of motor nuclei
Coordinates emetic process
Antiemetics for peripheral cause of nausea/vomitting
prokinetics
Prokinetics eg
Domperidone
Metoclopramide
Antiemetics for CTZ centrally caused nausea and vomiting
D2 antagonist
D2 antagonist eg
Haloperidol
Antiemetics for other centrally caused nause and vomiting
H1 antagonist
H1 antagonist eg
cyclizine
Levomepromazine
Broad spectrum antiemetic
antagnoist at 5HT2, H1, A1
Granisetron
anti emetic 2nd line
5HT3 antagonist
Aprepitant
antiemetic 2nd line
neurokinin receptor antagonist
Nabilone
2nd line antiemetic
cannabinoid (specialist use only)
Laxative classes
Softner
Stimulant
Osmotic
Bulk forming
Softner eg
docusate
Stimulant eg
Senna
Bisacodyl
Osmotic eg
Movicol
Laxido
Lactulose
Bulk forming eg
Fybogel
Opiod induced constipation rx eg
Methylnaltrexone injection,
naloxegol
Glycerine
softening suppository
Bisacodyl
Stimulant suppository
Micralax
combined suppository
Arachas oil
softening enema
Phosphate
stimulant enema
Rx of diarrhoea
Loperamide
Opioids
Hyoscine butylbromide
Octreotide
Creon (steatorrhoea)
Xerostomia
dry mouth
Xerostomia mx
saliva substitute
saliva stimulant
Malignant obstruction mx
opioid for analgesia
antispasmodic for colic
Haloperidol
+/- octreotide
Antispasmodic eg
Hyoscine butylbromide
Octreotide
dry GI secretion
malignant bowel obstruction rx
WHO analgesic ladder
Non opioids
Weak opioids
Strong opioids
Non opioids
Paracematol
NSAID
Weak opioid eg
cocodamol (30/500)
Tramadol
Tapentadol
Strong opioid eg
Morphine
Diamorphine
Hydromorphone
Oxycodone
Fentanyl
Buprenorphine
Methadone
Adjuvant analgaesic
Amatryptiline
Gabapentin
Pregabalin
Steroids
Morphine metabolism
Liver metabolises to
- M3G (inactive)
- M6G (active)
Kidney -> excretion
How steroids work as analgesic
reduces oedema around tumour, reduce compression
Myoclonic jerks
opioid toxicity
symmetrical twitches
arms flexed (vs hepatic flap=arms extended)
Morphine hallucinations
Ants/moths/bats/rats crawling/flying
Arms coming down from the ceiling
Hallucinating a close relative
Pethidine use
labour
very short duration of action
doesnt distress fetal resp on delivery (still shouldnt be given within 2hours of delivery)
Strong opioid in liver failure
Methadone
Strong opioid in kidney failure
fentanyl
Calculation for break through pain dose of opioid
1/6th of total 24hr morphine dose
How much to increase opioid dose by if no pain relief
Increase total 24hr dose by 1/3rd
How long does opioid induced constipation last?
Entire duration of opioid use
How long does opioid induced N/V last?
~ 1 wk