Glyceryl Trinitrate

Glyceryl Trinitrate

[50mg in 50ml $8.19]

ADMINISTRATION ROUTES:

  • IV, Sublingual, Transdermal

ALTERNATIVE NAMES:

  • Nitronal, Lycinate, Glytrin, Nitrolingual, Minitran, Nitroderm

ICU INDICATIONS:

  1. afterload reduction/peripheral vasodilation
  2. treatment of hypertension
  3. treatment of angina

PRESENTATION AND ADMINISTRATION:

  • IV:
    Nitronal 50ml contains 50mg of GTN in 50ml of 5% dextrose
    Use undiluted GTN is readily absorbed into many plastics. Original Perfusor PE tubing causes minimal absorption and is preferred. If other plastics are used, GTN may be absorbed by the tubing particular when running at low rates.
    IT SHOULD BE NOTED THAT WHEN THE APPROPRIATE INFUSION SETS ARE USED, THE CALCULATED DOSE WILL BE DELIVERED TO THE PATIENT BECAUSE THE LOSS OF NITROGLYCERIN DUE TO ABSORPTION IN STANDARD PVC TUBING WILL BE KEPT TO A MINIMUM. NOTE THAT THE DOSAGES COMMONLY USED IN PUBLISHED STUDIES UTILIZED GENERAL-USE PVC INFUSION SETS, AND RECOMMENDED DOSES BASED ON THIS EXPERIENCE ARE TOO HIGH IF THE LOW ABSORBING INFUSION SETS ARE USED.
    Compatible with the following IV fluids:
    5% dextrose, normal salin,e glucose and sodium chloride
    Do not mix with other medications Store at room temperature and protect for light
  • Transdermal:
    Apply once daily to chest or upper arm for 12-18 hours (brand dependent) followed by a 6-12 hour nitrate-free period (usually overnight)
    Minitran 5mg/24 hours and 10mg/24 hours
    Nitroderm TTS 5mg/24 hours (25mg) and 10mg/24 hours (50mg)
  • Sublingual tablets:
    Lycinate 600mcg tablets
  • Sublingual spray:
    Glytrin spray 400mcg/dose Nitrolingual pump spray 400mcg/dose

DOSAGE:

  • IV infusion:
    IV infusion dose range is 0-12ml/hr (equivalent to 0-200mcg/min). In ICU it is usually appropriate to commence the infusion at 5ml/hr and to titrate to effect.
  • Transdermal:
    Usually commence with 5mg/24 hours patch; maximum two 10mg/24 hours patches
  • Sublingual tablets:
    1 tablet under the tongue every 3-5 minutes as required

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

  • Dose as in normal renal function

DOSAGE IN PAEDIATRICS:

  • IV infusion:
    <30kg: 3mg/kg in 50ml 5% dextrose at 0.5-5ml/hr (0.5-5mcg/kg/min)
    >30kg: 3mg/kg in 100ml 5% dextrose at 1-10ml/hr (0.5-5mcg/kg/min)

CLINICAL PHARMACOLOGY:

  • The principal pharmacologic action of nitroglycerin is relaxation of vascular smooth muscle, producing a vasodilator effect on both peripheral arteries and veins with more prominent effects on the latter. Dilation of the postcapillary vessels, including large veins, promotes peripheral pooling of blood and decreases venous return to the heart, thereby reducing left ventricular end-diastolic pressure (preload). Arteriolar relaxation reduces systemic vascular resistance and arterial pressure (afterload).

CONTRAINDICATIONS:

  1. known hypersensitivity to glyceryltrinitrate

WARNINGS

  • Occasionally, high dose GTN may lead to worsened oxygenation due to increased shunting

PRECAUTIONS

  • General:
    GTN may lead to severe hypotension in patients with haemodynamically significant aortic stenosis.
  • Laboratory Tests:
    No tests in addition to routine ICU tests are required
  • Drug/Laboratory Test Interactions:
    None of note

IMPORTANT DRUG INTERACTIONS FOR THE ICU

  • Amplification of the vasodilatory effects of nitroglycerin by sildenafil can result in severe hypotension. Additive effects may be observed when GTN is combined with other antihypertensives

ADVERSE REACTIONS

  • Body as a Whole:
    Allergic reactions
  • Cardiovascular System:
    Tachycardia, hypotension, syncope, rebound hypertension, palpitations
  • Gastrointestinal System:
    Nausea, vomiting, abdominal pain
  • Central Nervous System:
    Headache
  • Haematological System:
    Methemoglobinemia

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