Opioids (general)

Question 1

MoA

Answer 1

Acts on opioid receptors in the brain, spinal cord and other nervous tissue to relieve pain

Question 2

Weak opioids

Answer 2

• Codeine (CD5, injections = CD2)
• Dihydrocodeine (CD5)
• Meptazinol (POM)

Question 3

Moderate opioids

Answer 3

Tramadol
- CD3
- Exempt from safe custody requirements

Question 4

Strong opioids

Answer 4

• Morphine
• Oxycodone
• Diamorphine
• Buprenorphine (S/L or 3/4/7 day pacthes)
• Fentanyl (72 hr patch or injection)
• Methadone
• Hydromorphone

All CD2, except buprenorphine which is CD3

Question 5

Others

Answer 5

Pethidine
- Used in labour
- If accumulates = convulsions

Tapentadol
- Less nausea, vomiting and constipation than other strong opioids.

Question 6

Breakthrough pain

Answer 6

• 1/10th or 1/6th of daily dose every 2-4 hours PRN
• Must be IR preparations

Question 7

Opioid overdose

Answer 7

Symptoms = pinpoint pupils, coma, respiratory depression
Antidote = naloxone

Question 8

Naloxone

Answer 8

Opioid receptor antagonists
Reverses respiratory depression
- Effects of buprenorphine are only partially reversed.
Can be supplied without a prescription by drug treatment services for the purpose of saving a life in an emergency e.g. heroin

Question 9

Opioids - side effects

Answer 9

NERDSCeverything
(nerds see everything)
- N + V
- Euphoria, hallucinations
- Reduced concentration + confusion
- Dry mouth
- Sedation
- Constipation

Question 10

N + V

Answer 10

Frequently with morphien
Give an antiemetic at start of treatment
- Prokinetic drug e.g. metoclopramide

Question 11

Euphoria

Answer 11

Common with morphine

Question 12

Sedation

Answer 12

Alcohol enhances this effect.
Driving may be impaired.

Question 13

Constipation

Answer 13

Faecal softener + peristaltic stimulant
e.g. Senna + Lactulose

Question 14

Larger doses - side effects

Answer 14

Respiratory depression
Hypotension
Pupil constriction
Muscle rigidity

Question 15

Long term use - side effects

Answer 15

Hypogonadism
- Reduced fertility
- Amenorrhoea
- ED
Adrenal insufficiency
Hyperalgesia
- Reduce dose or switch

Question 16

Respiratory depression

Answer 16

Major concentration
Treatment:
- Artificial ventilation
- Naloxone

Question 17

Dependence

Answer 17

Becomes apparent on withdrawal
Avoid abrupt withdrawal after long-term treatment

Question 18

Tolerance

Answer 18

Larger doses needed to achieve same level of analgesia

Question 19

Contraindications

Answer 19

• Comatose patients
• Risk of paralytic ileus (reduced GI motility)
• Respiratory depression (avoid in asthma attacks/COPD)
• Head injury or raised intraocular pressure (interact with pupillary responses vital for neurological assessment)

Question 20

Interactions - increased sedation

Answer 20

• Antidepressants
• Antihistamines
• Antipsychotics
• Antiepileptics
• Alcohol
• Benzodiazepines (also cause respiratory depression)
• Z drugs

Question 21

Interactions - CNS excitation or depression

Answer 21

Hypertension
Hypotension
MAOIs

Question 22

Cautionary labels

Answer 22

Warning: this medicine may make you sleepy. If this happens do not drive or use tools or machines. Do not drink alcohol

Question 23

Side effects - SUMMARY

Answer 23

“MORPHINE”
- Miosis (pinpoint pupils), muscle rigidity
- Out of it (sedation)
- Respiratory depression
- Postural hypotension
- Hyperalgesia, hallucinations
- Infrequency (constipation + urinary retention)
- N + V
- Euphoria

Question 24

Methadone

Answer 24

Used in opioid dependence
OD
More sedating
Long half life
- Accumulates = toxicity
Side effects
- QT prolongation

Question 25

When would methadone be given?

Answer 25

Long history of opioid misuse
Increased anxiety during withdrawal
Abuses sedative drugs/alcohol

Question 26

Buprenorphine - opioid dependency

Answer 26

OD
Less sedating
Safer
- can be used with other sedatig drugs
- less interactions
Milder withdrawal reaction
Lower risk of overdose

Question 27

Buprenorphine - when to take (opioid dependency)

Answer 27

Take first dose on withdrawal signs
Take first dose 6-12 afters hour after OR 24-48 hours after methadone.