Isosorbide Dinitrate

Cardiac Therapy · Nitrate

Indications

Angina prophylaxis and treatment. Acute attack of angina. Acute congestive heart failure including after myocardial infarction and chronic congestive heart failure as adjunctive therapy.

Dosage

ORAL: Elderly should be given lowest recommended daily dose initially then titrate upward. Angina: Adults: 5-40 mg 4 times/day or 40 mg every 8-12 hr in sustained-release dosage form. Congestive heart failure: Adults: Initial dose 10 mg 3 times daily; target dose 40 mg 3 times daily; max dose 80 mg 3 times daily. Sublingual Tab: 2.5-10 mg every 4-6 hr. Children: Not recommended. INJECTION: Adults: IV infusion, 2-10 mg/hr, higher doses up to 20 mg/hr may be required. Children: Not recommended.

Administration

By IV infusion diluted to a max concentration of 0.05% in NS or D5W. Also administered as an intra-coronary bolus inj during percutaneous transluminal coronary angioplasty.

Adverse Effects

Postural hypotension, tachycardia (but paradoxical bradycardia also reported); throbbing headache, dizziness; less commonly nausea, vomiting, heartburn, flushing, syncope, temporary hypoxaemia, rash, application site reactions with transdermal patches; very rarely angle-closure glaucoma. Injection Specific side-effects include severe hypotension, diaphoresis, apprehension, restlessness, muscle twitching, retrosternal discomfort, palpitation, abdominal pain; prolonged administration has been associated with methaemoglobinaemia.

Risk Factor (Pregnancy/Lactation)

Pregnancy: Risk cannot be ruled out. Lactation: Caution advised or effect undetermined. Contraindications: Hypersensitivity to nitrates, hypotensive conditions and hypovolaemia, hypertrophic cardiomyopathy, aortic stenosis, cardiac tamponade, constrictive pericarditis, mitral stenosis, toxic pulmonary oedema, head trauma, cerebral haemorrhage, cerebrovascular disease, marked anaemia, raised intracranial pressure, extreme bradycardia, closed-angle glaucoma, G6PD deficiency. Precautions: Hypothyroidism; malnutrition; hypothermia; recent history of myocardial infarction; heart failure due to obstruction; hypoxaemia or other ventilation and perfusion abnormalities, severe renal or hepatic impairment, orthostatic dysfunction. Head trauma, cerebral haemorrhage. Susceptibility to angle-closure glaucoma; metal-containing transdermal systems should be removed before magnetic resonance imaging…

Interactions

Sildenafil, tadalafil, vardenafil, ethanol, heparin, alteplase, ergot alkaloids, PDE5 inhibitors, other nitrates, hypotensive agents, sapropterin.

Advice to Patient

Take 30 minutes before meals. Take at same time each day, as prescribed. Chew chewable tablets well and keep them in mouth for 1 to 2 minutes before swallowing. Allow sublingual tablets to dissolve under tongue, do not chew or swallow them. Swallow sustained release capsules whole with a glass of water, do not crush or chew them. Contact prescriber if there is acute headache, rapid heartbeat, chest pain, unusual restlessness, dizziness, rash, muscular weakness or blurred vision. Do not stop taking medication abruptly, decrease dosage gradually. Avoid alcohol. Carry isosorbide at all times. Change position slowly.

Pharmacokinetics

Onset: SL: 2-5 mins. Oral: <1 hr. Duration: SL: 1-2 hrs. Oral: 4-6 hrs. Absorption: SL: Readily absorbed from the oral mucosa. Topical: Readily absorbed through the skin from an ointment. Oral: Readily absorbed. Metabolism: Taken up by smooth muscle cells of blood vessels and the nitrate group is cleaved to inorganic nitrite and then to nitric oxide. Also rapidly metabolized hepatically. Bioavailability: Oral: Due to extensive first-pass metabolism in the liver and pre-systemic clearance, bioavailability is reduced. The average bioavailability is about 25%. Half-life elimination: SL: 45-60 mins. IV: 20 mins. Oral: 4 hrs. Excretion: Renal.

Compiled by Healify Pharmacy from published drug references. How we compile it →

Always consult a pharmacist or doctor.