Cancer and Palliative Drugs

Question 1

Paracetamol indications

Answer 1

Pain

Fever (anti-pyrexial)

Question 2

Consequences/mechanism of paracetamol overdose

Answer 2

Liver failure:

• Metabolised by cP45, forming a toxic metabolite which is eliminated
• Overdose saturates elimination pathway
• Toxic metabolite (NAPQI) causes liver necrosis

Question 3

Paracetamol dose

Answer 3

0.5-1g ever 4-6 hours

MAX: 4g per day

Question 4

Codeine indications

Answer 4

Mild-moderate pain (e.g. post-op)

Question 5

Codeine MOA

Answer 5

Metabolised by liver to produce small amounts of morphine.

Question 6

IV Codeine effects

Answer 6

Anaphylaxis-like reaction

DO NOT GIVE IV

Question 7

Doses of codeine

Answer 7

Regular or PRN

30mg 4 hourly

Question 8

Co-codamol doses

Answer 8

Combination of paracetamol and codeine

E.g. 15/500 = 15mg codeine, 500mg paracetamol

Question 9

MST indications

Answer 9

Modified release morphine. Lasts 12 hours.

Chronic pain relief

Reduce breathlessness/anxiety in EOL and pulmonary oedema

Question 10

Morphine MOA

Answer 10

Activates opioid μ receptors in CNS, reducing neuronal excitability and pain transmission.

Blunts response to hypoxia, reducing respiratory drive and breathlessness

Question 11

Side effects of opioids

Answer 11

Nausea/vomiting (transient)

Constipation

Drowsiness

Itchy skin/sweating

Euphoria/hallucinations

Tolerance/dependence

Question 12

MST contra-indications

Answer 12

Renal impairment (eGFR <50)

It is renally eliminated

Question 13

MST doses

Answer 13

Determined by 24 hour use of immediate release morphine (e.g. oramorph).

Orally = dose is BD

Question 14

Morphine doses at EOL

Answer 14

Opioid naive: 20-30mg SC over 24 hours

Question 15

Oramorph indications

Answer 15

Immediate release morphine.

Acute, severe pain relief.
Lasts 20-30 mins.

Question 16

Oramorph dose and administration

Answer 16

IV, IM, SC or oral

2-10mg depending on age, weight + background dose of morphine

Question 17

Metoclopramide drug type and MOA

Answer 17

Dopamine antagonist (prokinetic)

Prevents stimulation of d2 receptors in CTZ.

Prevents stimulation of d2 receptors in the gut, increasing gastric emptying.

Question 18

Metoclopramide indications

Answer 18

Chemotherapy induced n+v

n+v due to delayed gastric emptying (e.g. opioids, gastroparesis)

AVOID IN PARKINSON’s (crosses blood-brain barrier)

Question 19

Cyclizine drug type and MOA

Answer 19

Anti-histamine.

Blocks h1 receptors in VC

Some anti-muscarinic properties

Question 20

Cyclizine indications and dose

Answer 20

N+V due to vertigo, motion sickness and high ICP

Mechanical bowel obstruction (anti-muscarinic)

50mg 8 hourly

Question 21

Haloperidol drug type and indications

Answer 21

Dopamine antagonist (anti-psychotic)

N+V due to toxins, radiotherapy and metabolic causes (e.g. renal failure)

AVOID IN PARKINSON’s (crosses blood-brain barrier)

Question 22

Levomepromazine

Answer 22

Anti-emetic (anti-psychotic dopamine antagonist)

Wide spectrum, give when others have not worked

Question 23

Domperidone

Answer 23

Dopamine antagonist (prokinetic)

Chemotherapy induced n+v

n+v due to delayed gastric emptying (e.g. opioids, gastroparesis)

Question 24

Dexamethasone

Answer 24

Useful synergist

Chemotherapy induced n+v

n+v due to raised ICP (e.g. brain tumour)

Question 25

Drugs for EOL care (4)

Answer 25

Analgesia = diamorphine

Anti-emetic = levomeprozamine

Anti-secretory = hyoscine butylbromide

Anti-agitation = miadazolam