Nitrates : Isosorbide Mononitrate

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Nitrates : Isosorbide Mononitrate

Trade names: Isoral, Cordil, Isotard

Class: coronary vasodilating effect

Pregnancy: (Category C)

Action:
§ The principal pharmacological action of isosorbide dinitrate is relaxation of vascular smooth muscle and consequent dilatation of peripheral arteries and veins, especially the latter.
§ Dilatation of the veins promotes peripheral pooling of blood and decreases venous return to the heart, thereby reducing left ventricular end- diastolic pressure and pulmonary capillary wedge pressure (preload).
§ Arteriolar relaxation reduces systemic vascular resistance, systolic arterial pressure, and mean arterial pressure (afterload).
§ Dilatation of the coronary arteries also occurs

Uses:

• Prophylaxis and treatment of acute angina pectoris.
• Treatment of chronic angina pectoris.
• Testament of hypertension associated with MI or CHF.
• Nitroglycerin ointment for treatment of Raynaud’s disease.

Dose:

Isosorbide Mononitrate : initially 20 mg 2–3 times daily or 40 mg twice daily (10 mg twice daily in those who have not previously received nitrates); up to 120 mg daily in divided doses if required

Isosorbide Dinitrate By mouth, daily in divided doses, angina 30–120 mg, left ventricular failure 40–160 mg, up to 240 mg if required
By intravenous infusion, 2–10 mg/hour; higher doses up to 20 mg/hour may be required

Contraindications:

· Sensitivity to nitrates Hypotension.

· Sever anemia.

· Hypotension.

· Head trauma.

· Cerebral hemorrhage.

Side effects:

1. Headache, syncope, dizziness.

2. Postural hypotension, transient flushing, and palpitation.

3. Topical application may lead to dermatitis.

v Drug interaction: Antihypertensive agents, Beta-adrenergic blocking agents, and calcium-channel blocking agent (they may lead to additive hypotension.

Nursing considerations:

• medications should be taken on an empty stomach.
• Carry sublingual tablets in a glass bottle, tightly capped.
• If anginal pain is not relieved in 5 minutes by first sublingual tablet, to take up to 2 more tablets at 5 minutes interval. If pain has not subsided 5 minutes after the 3rd tablet, client should be taken to the emergency room.
• Take sublingual tablets 5-15 minutes prior to any situation likely to cause anginal pain such as climbing stairs.
• Take sublingual tablets while sitting to avoid postural hypotension.