ISOSORBIDE DINITRATE (eye-soe-sor'bide) Coronex , Dilatrate-SR, Iso-Bid, Isordil, Isotrate, Novosorbide , Sorbitrate, Sorbitrate SA Classifications: cardiovascular agent; nitrate vasodilator Prototype: Nitroglycerin Pregnancy Category: C
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2.5 mg, 5 mg, 10 mg sublingual tablets; 5 mg, 10 mg chewable tablets; 5 mg, 10 mg, 20 mg, 30 mg, 40 mg tablets; 40 mg sustained release tablets, capsules
Organic nitrate with pharmacologic actions similar to those of nitroglycerin. Relaxes vascular smooth muscle with resulting
vasodilation. Dilation of peripheral blood vessels tends to cause peripheral pooling of blood, decreased venous return to
heart, and decreased left ventricular end-diastolic pressure, with consequent reduction in myocardial oxygen consumption.
Has an antianginal effect by causing vasodilation of the coronary arteries.
Relief of acute anginal attacks and for management of long-term angina pectoris.
Alone or in combination with a cardiac glycoside or with other vasodilators (e.g., hydralazine, prazosin, for refractory CHF;
diffuse esophageal spasm without gastroesophageal reflux and heart failure).
Hypersensitivity to nitrates or nitrites; severe anemia; head trauma; increased intracranial pressure. Safe use during pregnancy
(category C) or lactation is not established.
Glaucoma, hypotension, hyperthyroidism.
Angina Prophylaxis Adult: PO Regular tablets 2.530 mg q.i.d. a.c. and h.s.; Sublingual tablet 2.510 mg q46h; Chewable tablet 530
mg chewed q23h; Sustained release tablets 40 mg q612h
Acute Anginal Attack Adult: PO Sublingual tablet 2.510 mg q23h prn; Chewable tablet 530 mg chewed prn for relief
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Oral
- Do not confuse with isosorbide, an oral osmotic diuretic.
- Give regular oral forms on an empty stomach (1 h a.c. or 2 h p.c.). If patient complains of vascular headache, however, it
may be taken with meals.
- Advise patient not to eat, drink, talk, or smoke while sublingual tablet is under tongue.
- Instruct patient to place sublingual tablet under tongue at first sign of an anginal attack. If pain is not relieved, repeat
dose at 510 min intervals to a maximum of 3 doses. If pain continues, notify physician or go to nearest hospital emergency
room.
- Chewable tablet must be thoroughly chewed before swallowing.
- Do not crush sustained release form. It must be swallowed whole.
- Have patient sit when taking rapid-acting forms of isosorbide dinitrate (sublingual and chewable tablets) because of the possibility
of faintness.
- Store in tightly closed container in a cool, dry place. Do not expose to extremes of temperature.
Body as a Whole: Hypersensitivity reaction, paradoxical increase in anginal pain, methemoglobinemia (overdose). CNS: Headache, dizziness, weakness, lightheadedness, restlessness. CV: Palpitation, postural hypotension, tachycardia. GI: Nausea, vomiting. Skin: Flushing, pallor, perspiration, rash, exfoliative dermatitis.
Drug: Alcohol may enhance hypotensive effects and lead to cardiovascular collapse; antihypertensive agents, phenothiazines add to hypotensive effects.
Absorption: Significant first pass metabolism with PO absorption, with 1090% reaching systemic circulation. Onset: 25 min SL; within 1 h regular tabs; within 3 min chewable tabs; 30 min sustained release tabs. Duration: 12 h SL; 46 h regular tabs; 0.52 h chewable tabs; 68 h sustained release tabs. Metabolism: Metabolized in liver. Elimination: 80100% excreted in urine within 24 h.
Assessment & Drug Effects
- Monitor effectiveness of drug in relieving angina.
- Note: Headaches tend to decrease in intensity and frequency with continued therapy but may require administration of analgesic and
reduction in dosage.
- Note: Chronic administration of large doses may produce tolerance and thus decrease effectiveness of nitrate preparations.
Patient & Family Education
- Make position changes slowly, particularly from recumbent to upright posture, and dangle feet and ankles before walking.
- Lie down at the first indication of light-headedness or faintness.
- Keep a record of anginal attacks and the number of sublingual tablets required to provide relief.
- Do not drink alcohol because it may increase possibility of light-headedness and faintness.
- Do not breast feed while taking this drug without consulting physician.