GTN

Question 1

What are the indications for GTN?

Answer 1

• Myocardial Ischaemia
• STEMI
• Cardiogenic pulmonary oedema
• Control of hypertension associated with autonomic dysreflexia
• Control of hypertension (usually in conjunction with labetalol) prior to fibrinolytic treatment for STEMI.
• Control of hypertension (usually in conjunction with labetalol) during inter-hospital transfer for STEMI.

Question 2

What are the contraindications for GTN?

Answer 2

• Known severe Allergy
• Systolic blood pressure below 110 mmHg
• HR below 40BPM
• HR above 150BPM
• Ventricular Tachycardia

Question 3

What are the precautions for GTN?

Answer 3

• STEMI involving the right ventricle (decrease in CO)
• The patient is frail
• Signs of shock (decrease in CO)
• Dysrhythmia (decrease in CO)
• Has taken Phosphodieterase inhibitor in the last 24 hours
• Known aortic and mitral stenosis (decrease in CO)

Question 4

What are the Dosages for GTN?

Answer 4

• MI: 0.4mg every 5 minutes
• STEMI: 0.4mg with caution
• CPO: 0.8mg every 5 minutes
• Control of hypotension: 0.4mg every 5 minutes

Question 5

What is the usual preparation for GTN?

Answer 5

Metered dose bottle delivering 0.4mg doses

Question 6

What is the MOA for GTN?

Answer 6

GTN (glyceryl trinitrate) is a vasodilator that mainly relaxes veins, with some effect on arteries. It likely works by increasing nitric oxide, which widens blood vessels.
GTN effects:
Reduces venous return (preload) → Less blood returns to the heart, lowering oxygen demand.
Dilates arteries (reduces afterload) → The heart pumps more easily, reducing oxygen demand.
Widens coronary arteries → May slightly improve blood flow to the heart.