UNCONTROLLED WHEN PRINTED
Introduction

Nitrates cause the relaxation of vascular smooth muscle resulting in:

  • Vasodilation
  • Peripheral pooling and reduced venous return
  • Reduced left ventricular and diastolic pressure (preload)
  • Reduced systemic vascular resistance (afterload)
  • Reduced myocardial energy and oxygen requirements
  • Relaxes spasm of coronary arteries

Pharmacology Review

Indications
  • Chest pain/discomfort of presumed cardiac origin not relieved by rest and reassurance with systolic BP > 90mmHg.
  • Acute Cardiac Pulmonary Oedema with systolic BP >90mmHg.
  • Autonomic Dysreflexia with systolic BP > 160mmHg.
Contraindications
  • Hypersensitivity
  • Hypotension < 90mmHg
  • Medications used for erectile dysfunction within 24 hours (e.g. SildenafilĀ®, VardenafilĀ®)
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.
  • Do not shake GTN bottle prior to administration.
  • Assess BP before every dose.
  • Severe hypotension is an uncommon side effect.
Management
Cardiac Chest Pain
  • 0.4mg (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 contra-indications.
Acute Cardiogenic Pulmonary Oedema
  • 0.4mg (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 contra-indications.
Autonomic Dysreflexia
  • 0.4mg (1 spray) sublingually.
  • Repeat doses at 5 minute intervals until symptoms resolve or systolic BP < 160mmHg.
Special Considerations
  • Hypotension (rare)
  • Tachycardia
  • Flushing
  • Headache

References
References
Presentation
Spray bottle containing 200x atomised sprays
GTN
Colour assist:

Document Control


Directorate
Clinical Services

Responsible Manager
Head of Clinical Services

Date of Issue

Date of Expiry

St John WA Ā© Copyright 2020. All Rights Reserved

Privacy Policy | Copyright Statement & Disclaimer