Morphine

Question 1

What is morphine?

Answer 1

Morphine (10mg/1mL ampule) is a narcotic analgesic that acts on the CNS by binding with opioid receptors, altering processes that affect pain perception and emotional response to pain. It also causes respiratory depression, vasodilation, decreases gag reflexes and slows AV node conduction.

Metabolised by the liver, kidney and lungs.

Onset: 5-10 mins IM, 2-5 min IV
Duration: 1-2 hrs
Half-life: 2 hrs

Question 2

Indications for morphine?

Answer 2

1. Significant pain
2. Sedation (CCP)
3. Autonomic dysreflexia (with SBP >160 mmHg)
   (a condition that emerges after a spinal cord injury, usually when the damage has occurred above the T6 level)

Note: Morphine is the preferred narcotic agent except in:

• allergy/ADR
• haemodynamic instability
• known/suspected kidney disease
• when NAS narcotic administration is preferred
• suspected ACS

Question 3

Contraindications for morphine?

Answer 3

1. Allergy/ADR

2. Kidney disease (renal failure)

Question 4

Precautions for morphine?

Answer 4

1. Hypotension
2. Respiratory tract burns
3. Respiratory depression and/or failure
4. Known addiction to narcotics
5. Concurrent MAOI therapy
6. Cardiac chest pain

Question 5

Side effects of morphine?

Answer 5

1. Bradycardia
2. Drowsiness
3. Hypotension
4. Nausea & vomiting
5. Pinpoint pupils
6. Respiratory depression

Question 6

What is the dose of morphine for an adult?

Answer 6

IM
Under 70 yrs
2.5mg to 10mg 
Repeated at up to 5mg every 10 min
Total max dose 20 mg 

Over 70 yrs/cachectic (low body weight) or frail
2.5mg to 5mg
Repeated at up to 5mg every 10 min
Total max dose 10 mg

IV 
Under 70 yrs
2.5mg to 5mg 
Repeated at up to 5mg every 5 min
Total max dose 20 mg 

Over 70 yrs/cachectic (low body weight) or frail:
2.5mg
Repeated at up to 2.5mg every 5 min
Total max dose 10 mg

SUBCUT - QAS clinical consult required in all circumstances

Question 7

What is the dose of morphine for a paediatric?

Answer 7

Less than 1 yr - QAS clinical consult required in all circumstances

Over 1 yr 
Significant pain:
IM 
200 microg/kg (rounded down to the nearest 5kg)
Single dose only 
10-15 kg - 2 mg (0.2 mL) 
15-25 kg - 3 mg (0.3 mL) 
25-30 kg - 5 mg (0.5 mL)

Significant pain & autonomic dysreflexia: 
Over 1 yr
100-200 microg/kg IM 
Single max dose 5mg 
Total max dose 200 microg/kg

100 microg/kg IV
Single max dose 2.5mg
Repeated at 50 microg/kg (max 2.5mg) at 5 min intervals
Total max dose 200 microg/kg