Isosorbide mononitrate and dinitrate

Isosorbide mononitrate and dinitrate

Drug monograph · NCLEX study reference
Trade names	Imdur, Isordil
Therapeutic class	Antianginal
Pharmacologic class	Organic nitrate
Onset / peak / duration	Mononitrate ER provides sustained effect; dinitrate shorter acting.
Half-life / level	Mononitrate half-life about 5 hours; no routine level.
Routes	PO (oral)
High-alert (ISMP)	No
Black box warning	None
Antidote / reversal	Supportive care; fluids for hypotension.
Pregnancy / lactation	Use only if clearly needed.

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Isosorbide mononitrate and dinitrate (brand names Imdur, Isordil) — Antianginal; Organic nitrate.

Identification

• Therapeutic class: Antianginal.
• Pharmacologic class: Organic nitrate.

Pharmacology

• Mechanism of action: Converts to nitric oxide, causing venous and some arterial dilation that reduces preload and myocardial oxygen demand.
• Onset / peak / duration: Mononitrate ER provides sustained effect; dinitrate shorter acting.
• Half-life / therapeutic level: Mononitrate half-life about 5 hours; no routine level.

Clinical use

• Indications: Prevention of angina (not for acute attacks).
• Usual dose, route, frequency: Mononitrate ER 30 to 120 mg PO each morning; dinitrate two to three times daily.
• Maximum dose / adjustments: A daily nitrate-free interval (often overnight) is required to prevent tolerance.

Safety

• Contraindications: Use with PDE-5 inhibitors (sildenafil, tadalafil), severe hypotension, increased intracranial pressure.
• Black box warning: None.
• Interactions: PDE-5 inhibitors (life-threatening hypotension), other antihypertensives, alcohol (food/drink).
• Pregnancy / lactation: Use only if clearly needed.
• High-alert: No.

Adverse effects

• Common side effects: Headache, dizziness, flushing, orthostatic hypotension.
• Serious effects to report: Severe hypotension, syncope.
• Antidote / reversal: Supportive care; fluids for hypotension.

Nursing process

• Assessment before administration: Blood pressure, headache history, PDE-5 inhibitor use.
• Interventions during therapy: Maintain the daily nitrate-free interval; rise slowly.
• Monitor: Blood pressure, frequency of angina.
• Evaluation / expected outcome: Reduced angina episodes.

Patient teaching

• Patient teaching: This is for prevention, not acute chest pain; headaches often ease over time.
• Notify provider if: Fainting, worsening chest pain.
• Administration tips: Mononitrate ER swallowed whole in the morning; never combine with erectile dysfunction drugs.