Morphine DTP

Vocabulary flashcards covering clinical pharmacology, indications, contraindications, special clinical notes, and adult/paediatric dosing protocols for morphine as issued by the Queensland Ambulance Service (QAS).

Drug Class

Narcotic analgesic

Pharmacology

Acts on the central nervous system by binding with opioid receptors, altering pain perception and emotional response to pain; combines to cause respiratory depression, vasodilation, decreases in the gag reflex, and slows AV node conduction.

Metabolism

Metabolised by the liver, kidney, and lungs.

Indications

1. Significant pain

2. Sedation

3. Autonomic dysreflexia (with systolic BP $> 160\,\text{mmHg}$).

Contraindications

1. Known allergy AND/OR Adverse Drug Reaction

2. Kidney disease (renal failure).

Precautions

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.

Side Effects

1. Bradycardia

2. Drowsiness

3. Hypotension

4. Nausea and/or vomiting

5. Pin point pupils

6. Respiratory depression.

Presentation

Ampoule containing $10\,\text{mg}/1\,\text{mL}$ morphine sulphate pentahydrate.

Pharmacokinetics

Onset: $5\text{--}10\,\text{minutes}$ (peak $20\text{--}30\,\text{minutes}$ IM) or $2\text{--}5\,\text{minutes}$ (peak $20\,\text{minutes}$ IV)

Duration: $1\text{--}2\,\text{hours}$

Half-life: $2\,\text{hours}$.

Adult Dosages

1. Significant pain: 2.5mg-5mg IV or 2.5mg-10mg IM, both repeated at up to 5mg every 5 minutes, no max dose.

2. Sedation: 2.5mg IV & IO, repeated every 5 minutes, no max dose.

Paediatric dosages

IM:

200microg/kg, single max dose 5mg repeated at 100microg/kg (max 2.5mg), 10 minute intervals, no max dose. (Significant pain and autonomic dysreflexia)

IV:

100microg/kg, single max dose 2.5mg, repeated every 5 minutes at 50microg/kg (max 2.5mg), no max dose (significant pain and autonomic dysreflexia)

IV & IO:

100microg/kg, single max dose 2.5mg, repeated PRN, no max dose (sedation)