NITROGLYCERIN
(nye-troe-gli'ser-in)
Cellegesic, Minitran, Nitro-Bid, Nitro-Bid IV, Nitrocap, Nitrodisc, Nitro-Dur, Nitrogard, Nitrogard-SR, Nitroglyn, Nitrol, Nitrolingual, Nitrong, Nitrong SR, Nitrospan, Nitrostat, Nitrostat I.V., Nitro-T.D., Transderm-Nitro, Tridil
Classifications: cardiovascular agent; nitrate vasodilator
Pregnancy Category: C

Availability

0.5 mg/mL, 5 mg/mL, 10 mg/mL injection; 0.3 mg, 0.4 mg, 0.6 mg sublingual tablets; 0.4 mg/spray translingual spray; 2 mg, 3 mg buccal tablets; 2.5 mg, 6.5 mg, 9 mg, 13 mg sustained-release tablets, capsules; 0.1 mg/h, 0.2 mg/h, 0.3 mg/h, 0.4 mg/h, 0.6 mg/h, 0.8 mg/h transdermal patch; 2% ointment

Actions

Organic nitrate and potent vasodilator that relaxes vascular smooth muscle by unknown mechanism, resulting in dose-related dilation of both venous and arterial blood vessels. Promotes peripheral pooling of blood, reduction of peripheral resistance, and decreased venous return to the heart. Both left ventricular preload and afterload are reduced and myocardial oxygen consumption or demand is decreased.

Therapeutic Effects

Therapeutic doses may reduce systolic, diastolic, and mean BP; heart rate is usually slightly increased. Produces antianginal, antiischemic, and antihypertensive effects.

Uses

Prophylaxis, treatment, and management of angina pectoris. IV nitroglycerin is used to control BP in perioperative hypertension, CHF associated with acute MI; to produce controlled hypotension during surgical procedures, and to treat angina pectoris in patients who have not responded to nitrate or beta-blocker therapy.

Unlabeled Uses

Sublingual and topical to reduce cardiac workload in patients with acute MI and in CHF. Ointment for adjunctive treatment of Raynaud's disease.

Contraindications

Hypersensitivity, idiosyncrasy, or tolerance to nitrates; severe anemia; head trauma, increased ICP; glaucoma (sustained-release forms). Also (IV nitroglycerin): hypotension, uncorrected hypovolemia, constrictive pericarditis, pericardial tamponade; pregnancy (category C), lactation.

Cautious Use

Severe liver or kidney disease, conditions that cause dry mouth, early MI.

Route & Dosage

Angina
Adult: Sublingual 1–2 sprays (0.4–0.8 mg) or a 0.3–0.6-mg tablet q3–5min as needed (max: 3 doses in 15 min) PO 1.3–9 mg q8–12h IV Start with 5 mcg/min and titrate q3–5min until desired response Transdermal Unit Apply once q24h or leave on for 10–12 h, then remove and have a 10–12 h nitrate free interval Topical Apply 1.5–5 cm (½–2 in) of ointment q4–6h
Child: IV 0.25–0.5 mcg/kg/min, titrate by 0.5–1 mcg/kg/min q3–5 min

Administration

Note: Drug forms appropriate for angina prophylaxis include ointment, transdermal unit, translingual spray, transmucosal tablet, and oral sustained release forms. Drug forms appropriate for acute angina include sublingual tablet, translingual spray, or transmucosal tablet.

Sublingual Tablet
Sustained-Release Buccal Tablet
Sustained-Release Tablet or Capsule
Translingual Spray
Transdermal Ointment
Transdermal Unit
Intravenous

Note: Verify correct IV concentration and rate of infusion in infants and children with physician.

  • Check to see if patient has transdermal patch or ointment in place before starting IV infusion. The patch (or ointment) is usually removed to prevent overdosage.
  • Be aware that when switching from IV to transdermal nitroglycerin, the IV infusion rate is reduced by 50% with simultaneous application of 5 or 10 mg/24 h transdermal patch.

PREPARE: IV Infusion: IV nitroglycerin is available in differing concentrations. Be attentive to the dilution, dosage, and directions for administration on each vial or ampul. Note that a number of nitroglycerin preparations are available prediluted. Other forms must be diluted in D5W or NS, usually to concentrations between 25–500 mcg/mL. Use only glass bottles and manufacturer-supplied IV tubing. Withdraw medication into syringe and inject immediately into the IV solution to minimize contact with plastic. Regular IV tubing can absorb 40–80% of nitroglycerin.  

ADMINISTER: IV Infusion: Give by continuous infusion regulated exactly by an infusion pump. IV dosage titration requires careful and continuous hemodynamic monitoring.  

INCOMPATIBILITIES Solution/additive: Hydralazine, phenytoin. Y-site: Alteplase.

  • Use only glass containers for storage of reconstituted IV solution. Polyvinyl chloride (PVC) plastic can absorb nitroglycerin and therefore should not be used. Non-polyvinyl-chloride (non-PVC) sets are recommended or provided by manufacturer.

Adverse Effects (1%)

CNS: Headache, apprehension, blurred vision, weakness, vertigo, dizziness, faintness. CV: Postural hypotension, palpitations, tachycardia (sometimes with paradoxical bradycardia), increase in angina, syncope, and circulatory collapse. GI: Nausea, vomiting, involuntary passing of urine and feces, abdominal pain, dry mouth. Hematologic: Methemoglobinemia (high doses). Skin: Cutaneous vasodilation with flushing, rash, exfoliative dermatitis, contact dermatitis with transdermal patch; topical allergic reactions with ointment: pruritic eczematous eruptions, anaphylactoid reaction characterized by oral mucosal and conjunctival edema. Body as a Whole: Muscle twitching, pallor, perspiration, cold sweat; local sensation in oral cavity at point of dissolution of sublingual forms.

Diagnostic Test Interference

Nitroglycerin may cause increases in determinations of urinary catecholamines and VMA; may interfere with the Zlatkis-Zak color reaction, causing a false report of decreased serum cholesterol.

Interactions

Drug: Alcohol, antihypertensive agents compound hypotensive effects; IV nitroglycerin may antagonize heparin anticoagulation. Vasodilating effects may be enhanced by sildenafil, vardenafil, or tadalafil, so this combination should be avoided.

Pharmacokinetics

Absorption: Significant loss to first pass metabolism after oral dosing. Onset: 2 min SL; 3 min PO; 30 min ointment. Duration: 30 min SL; 3–5 h PO; 3–6 h ointment. Distribution: Widely distributed; not known if distributes to breast milk. Metabolism: Extensively metabolized in liver. Elimination: Inactive metabolites excreted in urine. Half-Life: 1–4 min.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education


Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug