isosorbide

Produce vasodilation (venous greater than arterial).
Decrease left ventricular end-diastolic pressure and left ventricular end-diastolic volume (preload). Net effect is reduced myocardial oxygen consumption.
Increase coronary blood flow by dilating coronary arteries and improving collateral flow to ischemic regions.

Therapeutic effects:

Prevention of anginal attacks.

Pharmacokinetics ⬆ ⬇

Absorption: Isosorbide dinitrate undergoes extensive first-pass metabolism by the liver, resulting in 25% bioavailability; isosorbide mononitrate has 100% bioavailability (does not undergo first-pass metabolism).

Distribution: Unknown.

Metabolism/Excretion: Isosorbide dinitrate is metabolized by the liver to 2 active metabolites (5-mononitrate and 2-mononitrate). Isosorbide mononitrate is primarily metabolized by the liver to inactive metabolites; primarily excreted in urine as metabolites.

Half-Life: Isosorbide dinitrate: 1 hr; isosorbide mononitrate: 5 hr.

Time/Action Profile ⬆ ⬇

(cardiovascular effects)

ROUTE	ONSET	PEAK	DURATION
ISDN-PO	45–60 min	unknown	4 hr
ISMN-PO	30–60 min	unknown	7 hr
ISMN-ER	unknown	unknown	12 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Concurrent use of PDE-5 inhibitor or riociguat.

Use Cautiously in:

Volume depleted patients;
Right ventricular infarction;
Hypertrophic cardiomyopathy;
OB: Safety not established in pregnancy;
Lactation: Safety not established in breastfeeding;
Pedi: Safety and effectiveness not established in children;
Geri: Initial dose required in older adults due to potential for hypotension.

Adv. Reactions/Side Effects ⬆ ⬇

CV: hypotension, tachycardia, paradoxic bradycardia, syncope

Derm: flushing

GI: nausea, vomiting

Neuro: dizziness, headache

Misc: tolerance

Interactions ⬆ ⬇

Drug-drug:

Concurrent use of avanafil, sildenafil, tadalafil, or vardenafil may result in severe hypotension (do not use within 24 hr of isosorbide dinitrate or mononitrate); concurrent use contraindicated.
Concurrent use of riociguat may result in severe hypotension; concurrent use contraindicated.
Additive hypotension with antihypertensives, acute ingestion of alcohol, beta blockers, calcium channel blockers, and phenothiazines.

Route/Dosage ⬆ ⬇

Isosorbide Dinitrate

PO (Adults ): Prophylaxis of angina pectoris: 5–20 mg 2–3 times daily; usual maintenance dose is 10–40 mg every 6 hr.

Isosorbide Mononitrate

PO (Adults ): ISMO, Monoket: 5–20 mg twice daily with the 2 doses given 7 hr apart. Imdur: 30–60 mg once daily; may ↑ to 120 mg once daily (maximum dose = 240 mg/day).

Availability ⬆ ⬇

Isosorbide Dinitrate

(Generic available)

Tablets: 5 mg; 10 mg; 20 mg; 30 mg; 40 mg
In combination with: hydralazine (BiDil). See Appendix [not included in this PDA edition].

Isosorbide Mononitrate

(Generic available)

Tablets (Monoket): 10 mg; 20 mg
Extended-release tablets: 30 mg; 60 mg; 120 mg

Assessment ⬆ ⬇

Assess location, duration, intensity, and precipitating factors of anginal pain.
Monitor BP and pulse routinely during period of dose adjustment.

Lab Test Considerations:

Excessive doses may ↑ methemoglobin concentrations.

Implementation ⬆ ⬇

Isosorbide Dinitrate

PO: Do not administer around the clock to prevent tolerance to nitrate effect; allow nitrate-free interval for ≥14 hr. Twice-daily dosing may be administered at 8 am and 1 pm and 3 times daily dosing may be given at 8 am, 1 pm, and 6 pm.

Isosorbide Mononitrate

PO: Do not administer around the clock. Administer immediate release tablets twice daily with doses 7 hr apart (8 am and 3 pm); administer extended release tablet once daily in the morning upon rising with a half-glassful of fluid. DNC: Swallow extended-release tablets whole; do not break, crush, or chew. Extended release tablets that are scored may be split.

Patient/Family Teaching ⬆ ⬇

Instruct patient to take medication as directed, even if feeling better. Take missed doses as soon as remembered; doses of isosorbide dinitrate should be taken at least 2 hr apart; daily doses of isosorbide mononitrate should be taken 7 hr apart. Do not double doses. Do not discontinue abruptly.
Instruct patient to take last dose of day (when taking 2–4 doses/day) no later than 7 pm to prevent the development of tolerance.
Caution patient to make position changes slowly to minimize orthostatic hypotension.
May cause dizziness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
Advise patient to avoid concurrent use of alcohol with this medication. Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care professional before taking other Rx, OTC, or herbal products.
Inform patient that headache is a common side effect that should decrease with continuing therapy. Aspirin or acetaminophen may be ordered to treat headache. Notify health care professional if headache is persistent or severe. Do not alter dose to avoid headache.
Advise patient to notify health care professional if dry mouth or blurred vision occurs.
Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected, or if breastfeeding.

section name header

Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇

Time/Action Profile ⬆ ⬇

Contraind./Precautions ⬆ ⬇

Adv. Reactions/Side Effects ⬆ ⬇

Interactions ⬆ ⬇

Route/Dosage ⬆ ⬇

Availability ⬆ ⬇

Assessment ⬆ ⬇

Implementation ⬆ ⬇

Patient/Family Teaching ⬆ ⬇

Evaluation/Desired Outcomes ⬆ ⬇

US Brand Names ⬆ ⬇

Canadian Brand Names ⬆ ⬇

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