GLYCERYL TRINITRATE (GTN)

Question 0

PHARMACOLOGY OF GLYCERYL TRINITRATE (GTN)

Answer 0

Principally, a vascular smooth muscle relaxant

A potent venodilator- it reduces Cardiac output via reduced venous return

Question 1

PRESENTATION OF GLYCERYL TRINITRATE (GTN)

Answer 1

0.6 mg tablets

Transdermal GTN patch 50mg (0.4mg/hr release)

Question 2

ACTIONS OF GLYCERYL TRINITRATE (GTN) & ITS EFFECTS

Answer 2

Actions:

• Venous dilatation promotes venous pooling & reduces return to the heart = REDUCES PRELOAD
• Arterial dilatation reduces systemic vascular resistance and arterial pressure = REDUCES AFTERLOAD

Effects:

• Reduced myocardial O2 demand
• Reduced systolic, diastolic and mean arterial blood pressure, whilst usually maintaining coronary perfusion pressure
• Mild collateral coronary arterial dilatation may improve blood supply to ischaemic areas of myocardium
• Mild tachycardia secondary to slight fall in blood pressure
• Preterm labour: Uterine quiescence in pregnancy

Question 3

PRIMARY EMERGENCY INDICATIONS FOR GLYCERYL TRINITRATE (GTN)

List all 5

Answer 3

1. Chest pain with ACS
2. Hypertension associated with ACS
3. Acute LVF
4. Autonomic dysreflexia
5. Preterm labour (consult)

Question 4

CONTRAINDICATIONS FOR GLYCERYL TRINITRATE (GTN)

Answer 4

Pneumonic KISSHSVR

1. Known Hypersensitivity
2. Inferior STEMI with systolic BP < 160mmHg
3. Systolic blood pressure 150 bpm
4. Heart rate <50 bpm (excluding autonomic dysreflexia)
5. Sildenafil; Viagra or Levitra administration in the past 24hrs or Cialis administration in the previous 4 days
6. VT
7. Right ventricular Infarct

Question 5

PRECAUTIONS FOR GLYCERYL TRINITRATE (GTN)

List all 4

Answer 5

1. No previous administration
2. Elderly Pts
3. Recent MI
4. Concurrent use with other tocolytics ( Medications to suppress premature labour)

Question 6

ROUTE OF ADMINISTRATION FOR GLYCERYL TRINITRATE (GTN)

Answer 6

Sub-Lingual
Buccal
Transdermal
Infusion ( Interhospital transfer only)

Question 7

SIDE EFFECTS OF GLYCERYL TRINITRATE (GTN)

List all 5

Answer 7

Tachycardia
Hypotension
Headache
Skin flushing (uncommon)
Bradycardia (occasionally)

Question 8

ONSET & DURATION OF GLYCERYL TRINITRATE (GTN)

Answer 8

S/L
Onset:     30 sec - 2 min
Peak:       5 -10 min
Duration:  15 - 30 min
IV
Onset:       30sec - 1min
Peak:         3 - 5min
Duration:    15 - 30 min
TRANSDERMAL
Onset:        Up to 30 min
Peak:          2 hr

Question 9

DOSE OF GTN

Answer 9

ACS
BP>110 = 600 mcg Tablet, if symptoms persist repeat @ 5/60
* If no previous admission = 1/2 dose 300mcg tablet

BP>90 50mg patch upper torso/arms (0.4mg/hr. If BP drops <90 remove patch)