Glyceryl Trinitrate

Question 1

GTN
Type

Answer 1

Nitrate smooth muscle relaxant and vasodilator

Question 2

GTN
Presentation

Answer 2

White 300mcg or 600mcg sublingual tablet
metered dose pump spray - multiple patient use 400mcg/dose - 200 doses per bottle

Question 3

GTN
Actions

Answer 3

1. Arterial and venous vasodilation
2. Dilation of collateral coronary vessels

Question 4

GTN
Uses

Answer 4

1. Relieve cardiac pain of ischaemic origin
2. Relieve acute pulmonary oedema
3. management of autonomic dysreflexia

Question 5

GTN
Adverse Effects

Answer 5

HHOF
1. Hypotension
2. Headache
3. Flushing of the skin
4. Occasionally - bradycardia

Question 6

GTN
Contraindications

Answer 6

1. Do not administer if SBP <90mmHg
2. Do not administer if HR is <50/min (this dose not apply to patients with autonomic dysreflexia
3. Noting that patients of all genders are prescribed the following medications for a range of conditions:
   - do not administer GTN if patient has taken sildenafil (viagra), vardenafil (levitra) or avanafil (spedra) within the past 24hrs
   - following the last dose of tadalafil (cialis), do not administer GTN within 4-5 days in the elderly and those with renal impairment, or 3-4 days in all other patients
4. Known hypersensitivity.

Question 7

GTN
Precaution

Answer 7

Be cautious in the event of suspected right ventricular ischaemia/infarct - have fluids running and use nitrates with caution.

Question 8

GTN
Dose (chest pain)

Answer 8

Adult Only
1 tablet (600mcg) or 1 metered dose (400mcg) sublingually. repeat every 5 mins if pain persists, up to a total of 3 doses.

If patient has not previously used nitrates or if systolic BP is between 90-110mmHg, give 300mcg tablet. Repeat 300mcg tablet once, if necessary.

Question 9

GTN
Dose APO

Answer 9

Adult only
1 tablet sublingually (300 or 600mcg). Repeat every 5 mins if in severe respiratory distress (max. 1800 mcg)
OR
1 metered dose (400mcg), sublingually. repeat every 5 mins if in severe respiratory distress (max. 1600mcg)
If patient has not previously used nitrates or if SBP is between 90-110mmHg, give 300mcg tablet. repeat 300mcg tablet. Repeat 300mcg tablet once, if in severe respiratory distress.

Question 10

GTN
Dose Autonomic Dysreflexia

Answer 10

Adult: 300mcg tablet sublingually or 1 metered dose (400mcg) sublingually
if little or no effect - repeat up to two times (total 3 doses), with 5mins between doses, monitoring BP

Paed (12-16yrs) tablet use only
Half adult dose (150mcg) sublingually
If little or no effect - repeat up to two times (total 3 doses), with 5 mins between doses, monitoring BP.

Question 11

GTN
Notes and Administration

Answer 11

• Tablet should fizz under tongue if still potent
• Use tablets within 3 months of opening bottle
• the container MUST be dated when first opened
• Prior to use for the first time (ie when the bottle if first opened), prime the pumpspray by pressing the nozzle 5 times, directing away from any person or animal
• prior to subsequent uses, prime the pumpspray by pressing the nozzle once.
• during administration, the patient should be sitting, so that the bottle stays vertical
• pHold the nozzle head as close to the open mouth as possible and spray sublingually
• instruct the patient to close mouth immediately after each dose - do not inhale or swallow.
• following each use, wipe down the pumpspray with an alcohol wipe (discard is significantly contaminated)