Download Glyceryl Trinitrate

South Western Sydney Local Health District
Policy No: SWSLHD_GL2014_018
Date Issued:
Guideline Critical Care
Glyceryl Trinitrate (GTN)
Document Number:
SWSLHD_GL2014_018
Functional Sub-Group:
Clinical
Summary:
This guideline has been developed to ensure
standardized preparation and administration of
glyceryl trinitrate throughout the SWSLHD.
Approved by:
Clinical Quality Council
Publication (Issue) Date:
July 2014
Next Review Date:
July 2017
Replaces Existing Guideline:
No
Previous Review Dates:
None
Contents:
1. Introduction
2. Aims/Expected Outcomes
3. Principles
4. Definitions
5. References and Links
1.
Introduction:
This guideline has been developed to streamline the delivery of GTN throughout the
Local Health District. GTN is predominantly a venous vasodilating agent.
The risk addressed by this policy:
Patient Safety
2. The Aims / Expected Outcome of this policy:
GTN will be administered safely and without adverse side effects
SWSLHD_GL2014_018
Page 1 of 6
South Western Sydney Local Health District
Policy No: SWSLHD_GL2014_018
Date Issued:
Related Standards or Legislation
NSQHS Standard 1 Governance
National Standard 4 Medication Safety
Related Policies (if relevant)
PD2013_043 Medication Handling in NSW Public Hospitals
http://www0.health.nsw.gov.au/policies/pd/2013/pdf/PD2013_043.pdf
3. Principles
•
•
•
•
•
•
•
•
•
All care provided within SWSLHD will be in accordance with infection control, manual
handling and minimisation and management of aggression guidelines.
Medications are to be prescribed and signed by a medical officer/authorised nurse
practitioner (NP) unless required during an emergency.
All drugs administered during an emergency (under the direction of a medical
officer/authorised nurse practitioner) are to be documented during the event, then
prescribed and signed following the event.
Medications are to be given at the time prescribed (as close to the time as is possible
when multiple drugs require ‘same time’ administration and, when the nurse is caring
for more than one patient, recognition is given to a possible short delay to
administration – antibiotics and other lifesaving drugs are to be prioritised) and are to
be signed by the administering nurse.
Parenteral medication prescriptions and the drug are to be checked with a second
registered or endorsed enrolled nurse prior to administration. The “rights of drug
administration” must be followed: right: patient, drug, dose, route, administration, time,
reason for the drug and documentation.
Adverse drug reactions are to be documented and reported to a medical officer.
Medication errors are to be reported using the hospital electronic reporting system:
IIMS.
Guidelines are for adult patients unless otherwise stated.
This guideline is for administration of drugs in critical care areas only.
Actions1,2,3

Glyceryl trinitrate is a nitrate vasodilating agent that causes relaxation of vascular
smooth muscle. It produces dose related dilation of both arterial and venous beds.
Venous dilation predominates over dilation of the arterioles.

Reduces systolic, diastolic and mean arterial pressures and myocardial oxygen
consumption.

Peripheral pooling may reduce venous return to the heart, reducing left ventricular enddiastolic pressure (LVEDP) and pulmonary capillary wedge pressure (PCWP, preload).

Arterial relaxation reduces systemic vascular resistance (afterload) and there is
dilatation of the coronary arteries.

Effective coronary perfusion pressure is usually maintained, but can be compromised if
blood pressure falls excessively or an increased heart rate decreases diastolic filling
time.

Heart rate is usually slightly increased, presumably a reflex response to the fall in blood
pressure.

Half-life is estimated at one to four minutes.
Indications1,2

Ischaemic chest pain or angina pectoris.

Control of acute hypertension.

Acute left ventricular failure.
SWSLHD_GL2014_018
Page 2 of 6
South Western Sydney Local Health District

Policy No: SWSLHD_GL2014_018
Date Issued:
Congestive heart failure associated with acute myocardial infarction.
Contraindications

Hypersensitivity to GTN or a known idiosyncratic reaction to organic nitrates.

Hypotension or uncorrected hypovolaemia.

Increased intracranial pressure (e.g. head trauma or cerebral haemorrhage).

Constrictive pericarditis and pericardial tamponade.

Severe anaemia and arterial hypoxaemia.

Concomitant administration of GTN with Viagra (Sildenafil) as Sildenafil has been
shown to potentiate the vasodilatory effects of GTN, resulting in severe hypotension.

Obstructive cardiomyopathy especially with aortic, mitral stenosis and constrictive
pericarditis.
Precautions

After prolonged continuous infusion, activity and effect are reduced requiring increased
doses; consider alternate vasodilator.

Not for direct intravenous injection. The vial must be further diluted using either sterile
5% glucose or sterile 0.9% sodium chloride prior to infusion.

Non-PVC fluid bags and non-PVC administration line should be used for the
administration of GTN, due to the problem of glyceryl trinitrate absorption by PVC
tubing

GTN should only be used in acute myocardial infarction for treating definite left
ventricular failure. Avoid decreases in BP or reflex tachycardia, which may reduce
coronary perfusion and increase myocardial oxygen demand, resulting in extension of
ischaemia/injury.

Titrate carefully to avoid hypotension, which may adversely affect organ perfusion and
increase the risk of ischaemia and thrombus formation.

Observe where available, the PCWP as a decrease will precede arterial hypotension.

Administration of vasodilators to hypertensive patients has been suspected of causing
acute blindness.

Patients who have previously been treated with organic nitrates may require larger
doses to achieve the appropriate effect.

Glyceryl trinitrate may worsen hypoxaemia in patients with pulmonary disease or cor
pulmonale

Methaemoglobinaemia has been reported in association with GTN therapy.

GTN should be used with caution in patients with malnutrition, hypothermia,
hypothyroidism or hyperthyroidism.
Significant Interactions

Alcohol and Levodopa may cause further vasodilatation, hypotension and syncope.

Information on potential interaction with other drugs is poorly documented. Caution
should be observed if other drugs are given concomitantly during infusion of GTN as an
interaction may adversely affect the haemodynamic response to the drug. Careful
haemodynamic monitoring is essential.

Avoid ergot alkaloids as they may precipitate angina.

Tricyclic antidepressants, anticholinergic agents, vasodilators such as Hydralazine,
Minoxidil, Prazosin and antihypertensive agents (including calcium antagonists, betablockers, diuretics and ACE inhibitors), major tranquillizers and opioid analgesics may
potentiate the hypotensive effect of GTN. Caution should therefore be observed when
any of these drugs are given concomitantly with GTN. Dosage adjustment may be
required in these circumstances.

Aspirin and other nonsteroidal anti-inflammatory drugs may diminish the therapeutic
response to GTN.

The effects of Noradrenaline may be decreased when it is used concurrently with GTN.

The anticoagulant effect of Heparin may be decreased in patients receiving intravenous
GTN. The solvent propylene glycol may be responsible for this effect. Patients should,
therefore, be monitored to avoid inadequate anticoagulation. If intravenous GTN
SWSLHD_GL2014_018
Page 3 of 6
South Western Sydney Local Health District
Policy No: SWSLHD_GL2014_018
Date Issued:
therapy is discontinued in patients receiving Heparin, a reduction in heparin dosage
may be necessary.
Adverse Effects
• Headache, tachycardia, nausea, vomiting, apprehension, restlessness, muscle
twitching, retrosternal discomfort, palpitations, dizziness and abdominal pain.
• Hypotension, bradycardia and decreased arterial oxygen tension.
• Alcohol intoxication has been reported in patients receiving high dose intravenous
infusions. The propylene glycol content may lead to hyperosmolarity.
• Cutaneous flushing, weakness and drug rash or exfoliative dermatitis.
• Hypertension, methaemoglobinaemia, postural hypotension and syncope on assuming
upright posture.
• Withdrawal syndrome e.g. increased frequency of angina attack, blurred vision,
cyanosis (rarely), fainting/ lightheadedness and anaphylaxis.
Presentation
• GTN ampoules containing 50 mg/10 mL.
Administration Guidelines1,3,4
• GTN for Injection is a concentrated potent drug, which must be diluted in sterile 5%
glucose or sterile 0.9% sodium chloride prior to its infusion.
• Intravenous GTN can only be administered in the High Acuity Areas including ICU /
HDU, CCU Operating Rooms/Recovery and the Emergency Department where
patients can be cardiac monitored.
• The infusion once prepared is stable for 24 hours and should be replaced with a new
infusion preparation every 24 hours.
IV Infusion via volumetric pump: (Concentration of 50mg / 500ml =
100micrograms/Ml)
Preparation
• Dilute GTN prior to intravenous infusion (do not use GTN for direct intravenous
injection).
• Avoid skin contact with concentrated solution when preparing infusion.
• Aseptically withdraw and discard 10mL from a 500mL glass IV bottles / non-PVC fluid
bag of 5% glucose.
• Add one GTN 50mg/10mL ampoule to 490mL of 5%glucose giving a final
concentration of 50mg / 500ml = 100micrograms/mL
NB: Concentration may be increased but must not exceed 400 micrograms/mL
• GTN absorbs into many surfaces - to avoid absorption, glass IV bottles / non-PVC
fluid bags and appropriate non-PVC giving sets must be used.
Administration
• Commence at 5 -10microgram/minute (300 -600micrograms /hour = 3 - 6ml/hour)
delivered through an infusion pump.Titrate infusion according to pain response and to
maintain blood pressure in the target range.
• Usual dose range is 5 micrograms to 25 micrograms/minute (3mL to 15mL/hour).
• If systolic blood pressure falls below 90mm Hg, cease the infusion. If blood pressure
does not begin to increase within 5 minutes notify medical officer.
• Monitor blood pressure continuously via arterial line or every 2-3 minutes (if using
NIBP).
• Continue infusion at dose previously tolerated if blood pressure is stable.
Weaning:

Decrease rate by 3mL/hour (300 microgram/hour) every five minutes while
maintaining desired hemodynamic parameters.

Discard any unused GTN infusion after 24 hours and prepare new infusion if
required.
SWSLHD_GL2014_018
Page 4 of 6
South Western Sydney Local Health District
Policy No: SWSLHD_GL2014_018
Date Issued:
Cardiac Surgery routine:

Infusion is at 1mg/hour = 10mL/hour.

Weaning may be commenced when there are no further signs of vasospasm or ST
depression, and the patient is hemodynamically stable.

Commence weaning routinely at day 1 post surgery.

At 05.00 hours, reduce infusion to 8mL/hour.

At 06.00 hours, reduce infusion to 5mL/hour.

At 07.00 hours, reduce infusion to 3mL/hour.

At 08.00 hours, cease infusion.

Observe for ST segment changes in leads that will demonstrate changes according to
the site of previous myocardial injury/surgery (see Cardiac Monitoring protocol).

Chest pain is a late sign of myocardial ischemia/injury.
IV infusion via syringe driver : (50mg / 50ml = concentration of 1mg/mL or 1000
micrograms/mL

Dilute 50mg/10mL glyceryl trinitrate with 40mL sterile 5% glucose using a 50mL syringe
to give a final concentration of 1mg/mL or 1000 micrograms/mL.

Commence at 25 micrograms/minute or 1.5mL/hr; as per clinical studies.

Increase by 5 micrograms/minute (300 micrograms/hour or 0.3mL/hour) until desired
effect is achieved.

Monitor BP closely and cease increasing infusion if the systolic BP falls more than
20mmHg below baseline value. Maintain the infusion at an appropriate rate to achieve
target BP range.

When the patient is pain free (and ST segment changes have reverted), continue GTN
at that rate for 12 – 24 hours.

Commence weaning by reducing infusion by 0.3mL/hour, (300 microgram/hour) every
five minutes while maintaining desired hemodynamic parameters.

Observe for recurrence of pulmonary oedema in patients being treated for cardiac
failure.

Obtain a prescription for, and commence oral or topical nitrates when weaning the
infusion has been weaned to 300 micrograms/hour (0.3mL/hour).
Drug Dosage Table for IV infusion via syringe driver : (50mg / 50ml = concentration
of 1mg/mL or 1000 micrograms/mL
Rate in mL/hour
0.3
0.6
0.9
1.2
1.5
1.8
2.1
2.4
2.7
3.0
3.3
3.6
3.9
4.2
4.5
SWSLHD_GL2014_018
Dose in micrograms/minute
Dose in micrograms/hour
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
300
600
900
1200
1500
1800
2100
2400
2700
3000
3300
3600
3900
4200
4500
Page 5 of 6
South Western Sydney Local Health District
Policy No: SWSLHD_GL2014_018
Date Issued:
Clinical Considerations

Monitor continuously blood pressure, heart rate and pulmonary capillary wedge
pressure to enable appropriate titration of GTN. Patient should be on a cardiac monitor.

Monitor and set appropriate alarms for ST segment monitoring.

Adequate systemic blood pressure and coronary perfusion pressure must be
maintained.

Change the infusion and its administration set at 24-hour intervals.

Non-PVC fluid bags and administration set should be used for administration.

Do not mix GTN with other drug infusions.
4.
1
2
3
4
5
References and links
MIMS Online, CIAP: NSW Health Department, Copyright MIMS Australia Pty Ltd. August 2012.
http://www.use.hcn.com.au
The Society of Hospital Pharmacists of Australia 2011, The Australian Injectable Drugs
th
Handbook, 5 Edition, SHPA publications, Australia.
eTherapeutic Guidelines: CIAP 2012, http://www.tg.org.au/
th
Thomas Reuters, Micromedex 2.0, http://www.micromedex.com/, viewed 27 August 2012.
Liverpool Hospital Intensive Care Unit Guidelines. 2013. Glyceryl Trinitrate, SWSLHD.
Author:
Reviewers:
E Longhurst, CNE HDU Bowral & District Hospital
Grant Isedale (Clinical Manager, Critical Care & Surgical Specialties SWSLHD, SWSLHD
Drug Advisory Committee
Bankstown ICU: Grant Bennet (ICU Director), Ruth Tabvuma (NUM), Kathleen Brennan
(NP).
Bankstown ED: Matthew Smith (ED Director), (NUM), Jenny Morris (CNC), Angela Duncan
(CNE)
Bowral ICU: William Quinn & Simon Grant (Physicians), Gail Hanger (NUM), Elizabeth
Longhurst (CNE).
Bowral ED: Matthew Bragg (ED Director), Daryn Mitford (NUM), Maie Pikkat
- (CNE).
Campbelltown ICU: Gillian Bishop (ICU Director), Bruce Nicholson (NUM), David Sanchez
(CNC), Steve Goodall (CNE).
Campbelltown ED: Sellappa Prahalath (ED Director), Stewart Watkins (Deputy Director),
Kelly-Ann Paddock (NUM), Ron Wilson (CNC), Ray Morgan (CNC), Ann Dillon (CNC).
Fairfield ICU: Jyotsna Dwivedi (ICU Director), Belinda Lloyd (NUM), Jane Gibson (CNE).
Fairfield ED: Harry Doan (ED Director), Belinda Pellizzon (NUM), Glenda Austin
(CNC),
Deborah Raymond (CNC).
Liverpool ICU: Michael Parr (ICU Director), Linda Williams (NM), Sharon Shunker (CNC),
Paula Nekic (CNE), Karla Lopez (CNE), Tony Bogdanovski (CNE).
Liverpool ED: Ian Ferguson (ED Director), Penny Weir (Deputy Director), Lyndal Marlow
(NM), Carlie Tighe (CNC), Kathryn Spears (CNE), Amanda Hawkins (CNE).
Pharmacicts: Madeline Eves, Eugenia Fiakos, Shivon Singh, Sue-Ellen Brown
SWSLHD_GL2014_018
Page 6 of 6