Glyceryl Trinitrate (GTN)

UNCONTROLLED WHEN PRINTED

Introduction

Nitrates cause the relaxation of vascular smooth muscle resulting in:

Also known as nitroglycerin

Indications

Chest pain/discomfort of presumed cardiac origin not relieved by rest and reassurance with systolic BP > 90 mmHg.
Acute Cardiac Pulmonary Oedema with systolic BP >90 mmHg.
Autonomic Dysreflexia with systolic BP > 160 mmHg.

Contraindications

Hypersensitivity
Hypotension < 90 mmHg
Recent use of medications used for erectile dysfunction:
- Sildenafil (Viagra®) or Vardenafil (Levitra®) or Avanafil (Spedra®) use in the previous 24 hours
- Tadalafil (Cialis®) use in the previous 3 days

Precautions / Notes

Nitrates are an early intervention and should not be delayed until on the stretcher or inside the ambulance
Administer to the patient in a seated or semi-recumbent position
Prime the bottle before using it for the first time by pressing the nozzle 5 times, spraying it into the air
Do not shake GTN bottle prior to administration
Assess BP before every dose
Severe hypotension is an uncommon side effect

COVID-19 / Febrile Respiratory Illness

Crews should allow the patient to administer their own GTN spray wherever possible
Allow patient to self-administer GTN spray under crew direction; stand clear and wait a minute before approaching the patient
If you have to use SJA supplied Glyceryl Trinitrate (GTN Spray), assess whether it can be reused and wipe with Clinell wipe after use. Discard the MDI in the sharps bin if the patient is very unwell or highly symptomatic of infectious respiratory condition.
Note: If administering St John supplied medication, crews are NOT to leave the remainder of the medication with the patient. This is a violation of the St John WA poisons licence and the Medicines and Poisons Act 2014.
No vehicle should be considered non-operational due to not having GTN available; if GTN is not available step up to the next level of pain relief.

Management

Cardiac Chest Pain

400 microg (1 spray) sublingually.
If pain persists after 5 minutes and BP maintained, consider further sprays of GTN at 5 minute intervals
Should the first 3 doses provide some relief but symptoms persist, continue with further doses at 5 minute intervals if no contraindications

Acute Cardiogenic Pulmonary Oedema

400 microg (1 spray) sublingually
If BP maintained, consider further sprays of GTN at 5 minute intervals
Should the first 3 doses provide some relief but symptoms persist, continue with further doses at 5 minute intervals if no contraindications

Autonomic Dysreflexia

400 microg (1 spray) sublingually.
Repeat doses at 5 minute intervals until symptoms resolve or systolic BP < 160mmHg.

Special Considerations

References

Presentation

Spray bottle containing 200x atomised sprays

Colour assist:

Directorate

Clinical Services

Responsible Manager

Head of Clinical Services

Date of Issue

Date of Expiry