Glyceryl Trinitrate GTN

Question 1

Glyceryl Trinitrate GTN Intro

Answer 1

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

Also known as nitroglycerin

Question 2

3 Glyceryl Trinitrate GTN Indications

Answer 2

• Chest pain/discomfort of presumed cardiac origin not relieved by rest and reassurance with systolic BP > 90mmHg where the heart rate is within 50-150 beats per minute.
• Acute Cardiac Pulmonary Oedema with systolic BP >90mmHg.
• Autonomic Dysreflexia with systolic BP > 160mmHg.

Question 3

4 Glyceryl Trinitrate GTN Contraindications

Answer 3

• Hypersensitivity
• Hypotension < 90mmHg
• Ventricular Tachycardia (VT)
• 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

Question 4

Glyceryl Trinitrate GTN Precautions / Notes

Answer 4

• 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.
• Intoxication (effect are enhanced)
• Phosphodiesterase 5 inhibitor medication administration in previous 4 days

Question 5

Glyceryl Trinitrate GTN Special Considerations (Side Effects)

Answer 5

Hypotension (rare)
Tachycardia
Flushing
Headache
Dizziness