Glyceryl Trinitrate

Question 1

GTN: Introduction

Answer 1

Nitrates cause the relaxation of vascular smooth muscle resulting in:
1) Vasodilation
2) Peripheral pooling and reduced venous return
3) Reduced left ventricular and diastolic pressure (preload)
4) Reduced systemic vascular resistance (afterload)
5) Reduced myocardial oxygen and energy requirements
6) Relaxes spasm of coronary arteries

Question 2

GTN: Indications

Answer 2

Chest pain/discomfort of a presumed cardiac origin not relieved by rest and reassurance with a systolic BP of >90mmhg where the heart rate is with 50-150 beats per minute.

Acute cardiogenic pulmonary oedema with systolic BP >90mmhg

Autonomic dysreflexia with systolic BP >160mmhg

Question 3

GTN: Contraindication

Answer 3

Hypersensitivity

Hypotension <90 mmhg

Ventricular Tachycardia (VT)

Recent use of medications used for erectile dysfunction:
Sildenafil (24 hours)
Tadalafil (3 days)

Question 4

GTN: Considerations

Answer 4

HFTHD

Hypotension

Flushing

Tachycardia

Headache

Dizziness