Isosorbide Mononitrate: Comprehensive Drug Monograph

Pharmacokinetic Profile

Half-Life

~5 h (IR); apparent ~6.3 h (ER)

Metabolism

Hepatic denitration & glucuronidation; non-CYP

Protein Binding

~5%

Bioavailability

~100% (IR, no first-pass)

Volume of Distribution

0.6–0.7 L/kg

Clinical Information

Drug Class

Long-acting organic nitrate

Available Doses

IR: 10, 20 mg
ER: 30, 60, 120 mg

Route

Oral

Renal Adjustment

Not required

Hepatic Adjustment

Not required

Pregnancy

Former Cat. B; use only if clearly needed

Lactation

Excretion in milk unknown; caution

Schedule / Legal Status

Rx only; not a controlled substance

Generic Available

Yes (IR & ER)

Indications

Indication	Approved Population	Therapy Type	Status
Prevention of angina pectoris due to coronary artery disease	Adults with chronic stable angina	Monotherapy or adjunctive (with beta-blocker, CCB)	FDA Approved

Isosorbide mononitrate is the principal active metabolite of isosorbide dinitrate and carries a single FDA-approved indication: long-term prophylaxis of angina pectoris in chronic coronary disease. Its onset of action is too slow for the termination of an acute anginal episode — sublingual nitroglycerin (or sublingual isosorbide dinitrate) remains the agent of choice for breakthrough symptoms. Contemporary chronic coronary syndrome guidelines position long-acting nitrates as second-line antianginal therapy after beta-blockers or calcium channel blockers, or as an add-on agent when monotherapy fails to achieve symptom control.

Common Off-Label Uses

Heart failure with reduced ejection fraction (HFrEF) — the hydralazine-plus-nitrate strategy carries a Class I recommendation in self-identified Black patients with NYHA III–IV HFrEF on optimal background therapy. The pivotal A-HeFT trial used isosorbide dinitrate (not mononitrate); ISMN is sometimes substituted in practice for adherence advantages, but evidence supporting that substitution is extrapolated rather than direct. (Evidence quality: high for ISDN; low for ISMN substitution)

Esophageal motility disorders — diffuse esophageal spasm and achalasia, exploiting smooth-muscle relaxation of the lower esophageal sphincter. (Evidence quality: low — small case series)

Portal hypertension — adjunct to non-selective beta-blockade for variceal bleeding prophylaxis; reduces portal pressure but adds vasodilatory adverse effects. (Evidence quality: low — modest benefit; not first-line)

Cervical ripening — investigational at term induction of labour. (Evidence quality: very low — heterogeneous trials)

Dose

Dosing

Dosing is dictated by the formulation and the absolute requirement for a daily nitrate-free interval of 10–14 hours. Without this interval, hemodynamic and antianginal tolerance develops rapidly — typically within 24–48 hours of continuous exposure — and the antianginal benefit is lost. There is no FDA-approved intravenous formulation of isosorbide mononitrate.

Clinical Scenario	Starting Dose	Maintenance Dose	Maximum Dose	Notes
Chronic stable angina — IR formulation, headache-prone or nitrate-naïve	5 mg BID	10–20 mg BID	20 mg BID	First dose on awakening; second dose 7 hours later (asymmetric dosing) Standard schedule: 8 a.m. and 3 p.m.
Chronic stable angina — IR formulation, standard initiation	10 mg BID	20 mg BID	20 mg BID	Asymmetric 7-hour interval mandatory Higher than 20 mg BID does not improve efficacy and increases adverse effects
Chronic stable angina — ER formulation, initiation	30 or 60 mg once daily	60–120 mg once daily	240 mg once daily (rare)	Single morning dose; built-in nocturnal nitrate-free interval Per FDA label: 60 mg tablet is scored and divisible; 30 mg tablet must not be broken
Switch from IR to ER (adherence or simplification)	30–60 mg ER once daily	Titrate per response	240 mg once daily (rare)	Titration interval ≥3 days per FDA label Stop IR the morning of ER initiation
HFrEF — adjunctive (off-label, hydralazine + nitrate strategy)	30 mg ER once daily	60–120 mg ER once daily	120 mg once daily	A-HeFT used ISDN 20 mg TID; ISMN substituted in practice for once-daily simplicity (no direct mortality data) Combine with hydralazine 75 mg TID

Population-Specific Considerations

Population	Recommendation	Rationale
Pediatric (<18 y)	Not recommended — safety and efficacy not established	No supporting trial data; angina extremely rare in this group
Elderly (≥65 y)	Start at the lower end of the dosing range	Greater susceptibility to orthostatic hypotension and falls; reduced baroreceptor function
Renal impairment (any stage, including dialysis)	No dose adjustment	Half-life unchanged in chronic renal failure; metabolites are pharmacologically inactive
Hepatic impairment (cirrhosis)	No formal adjustment; titrate cautiously	Disposition similar to healthy subjects in formal studies
Pregnancy	Use only if clearly needed (former Pregnancy Category B)	No teratogenicity in animal studies up to ~100× human dose; no adequate human studies

Clinical Pearl — The 7-Hour Rule

For immediate-release ISMN, both daily doses are taken in the first half of the waking day (e.g., 8 a.m. and 3 p.m.). This counterintuitive schedule preserves a long nocturnal nitrate-free interval, prevents tolerance, and concentrates therapeutic levels during the daytime — when patients are most likely to exert themselves and provoke angina. Patients prescribed twice-daily ISMN with a 12-hour interval will lose efficacy within 1–2 weeks; this has been shown for both IR and 12-hour BID dosing of ER formulations.

Pharmacology

Mechanism of Action

Isosorbide mononitrate is a prodrug that liberates nitric oxide (NO) within vascular smooth muscle through enzymatic and non-enzymatic denitration. NO activates soluble guanylate cyclase, raising intracellular cyclic GMP and triggering myosin light-chain dephosphorylation. The resulting smooth-muscle relaxation is preferentially venous at therapeutic concentrations, lowering preload and reducing left ventricular wall tension and myocardial oxygen demand. At higher exposures, arterial dilation contributes — modestly reducing afterload and dilating epicardial coronary vessels, including stenotic segments and collaterals. Antianginal benefit therefore derives primarily from a favourable shift in myocardial oxygen supply-demand balance rather than from a direct chronotropic or inotropic effect.

ADME Profile

Parameter	Value	Clinical Implication
Absorption	Bioavailability ~100% for IR (no first-pass metabolism); Tmax 30–60 min (IR), 3–4 h (ER); food may delay (Tmax) but does not reduce extent (AUC)	No first-pass metabolism distinguishes ISMN from ISDN; can be taken without regard to meals
Distribution	Vd ≈ 0.6–0.7 L/kg; protein binding ~5%; distributes into total body water, blood cells, and saliva	Negligible displacement interactions; rapidly equilibrates with vascular smooth muscle
Metabolism	Hepatic denitration to isosorbide and glucuronide conjugates; not a CYP substrate; metabolites are inactive	Free of the major CYP-mediated drug interactions that complicate other cardiovascular therapies
Elimination	~96% urinary excretion within 5 days (chiefly inactive metabolites); ~2% unchanged; ~1% in feces; t½ ~5 h (IR), apparent t½ ~6.3 h (ER)	Renal failure does not require dose adjustment because metabolites are pharmacologically inert and t½ is unchanged

Side Effects

The adverse-effect profile is dominated by vasodilator-mediated symptoms — headache and orthostatic phenomena — that are most intense during the first week of therapy and clearly dose-dependent. Incidences below for headache and dizziness are taken from the integrated FDA Imdur extended-release pivotal trial table (three placebo-controlled North American studies); other frequencies, where stated, are taken from European SmPC pooled data.

≥10% Very Common

Adverse Effect	Incidence	Clinical Note
Headache	38–57% Dose-dependent: 38% at 30 mg, 51% at 60 mg, 42% at 120 mg, 57% at 240 mg; placebo 15%	The signature nitrate adverse effect. Frontal, throbbing, dose-related; almost always emerges within the first 1–3 doses and attenuates over 1–2 weeks of continued therapy. Per the FDA label, aspirin or acetaminophen often relieves the headache without compromising antianginal efficacy. Patients should not adjust the dosing schedule to avoid headaches because loss of headache may coincide with loss of antianginal effect.

1–10% Common

Adverse Effect	Incidence	Clinical Note
Dizziness	8–11% Placebo 4%; most prominent at 60 mg dose (11%)	Most prominent on standing; correlates with peak plasma levels 1–4 hours post-dose. Counsel slow positional changes.
Hypotension	4–5% European SmPC pooled data	Mostly orthostatic; symptomatic in volume-depleted, elderly, and patients on multiple antihypertensives. May be accompanied by paradoxical bradycardia.
Loss of appetite	~2.5% European SmPC pooled data	Generally transient and not a cause for discontinuation.
Nausea	~1% European SmPC pooled data	Usually mild; rarely a reason to discontinue.
Tiredness, sleep disturbances, GI upset	~6% SmPC: not greater than placebo	Reported in trials but at frequencies indistinguishable from placebo; causality uncertain.
Flushing, palpitations, dry mouth, asthenia	≤5% FDA label: pooled data, exact rate not tabulated	Class-typical vasodilator effects; flushing reflects cutaneous vasodilation, palpitations often reflect reflex sinus tachycardia mitigated by concomitant beta-blockade.

Serious Serious Adverse Reactions (regardless of frequency)

Adverse Effect	Estimated Frequency	Typical Onset	Required Action
Severe symptomatic hypotension / syncope	Rare (post-marketing reports)	Within hours of first dose	Place patient supine, elevate legs, IV crystalloid; withhold dose pending review of volume status and concomitant medications. Avoid epinephrine or arterial vasoconstrictors per FDA label.
Paradoxical bradycardia with hypotension	Rare	Acute dosing	Trendelenburg position, IV fluids; atropine for symptomatic bradycardia; discontinue therapy.
Methemoglobinemia	Very rare Generally requires overdose	High doses or overdose	Co-oximetry; IV methylene blue 1–2 mg/kg per FDA label if symptomatic or MetHb ≥10–20%. Note methylene blue is contraindicated in G6PD deficiency.
Rebound angina on abrupt withdrawal	Rare Documented in industrial nitrate workers	24–72 h after stopping	Resume nitrate; if discontinuation required, taper over ≥1 week and intensify alternative antianginal therapy.
Hemodynamic collapse with PDE5 inhibitor co-ingestion	Rare but life-threatening	Within 1–6 h of co-administration	Aggressive volume resuscitation; vasopressor support; avoid further nitrate; admit to a monitored bed.

Discontinuation Discontinuation Rates (per FDA Imdur ER pivotal trials)

Adults (active doses, pooled)

8% overall (30–240 mg)

Top reason: headache (predominant cause across all doses; dizziness was rarely a reason for withdrawal).

Pediatric

N/A not approved

Safety and efficacy not established; off-label paediatric use is rare and unsupported by formal data.

Reason for Discontinuation	Incidence	Context
Headache	5–8% FDA label, dose-dependent (30 mg: 5%, 60 mg: 8%, 120 mg: 5%, 240 mg: 8%); placebo 0%	Single most common cause of nitrate withdrawal across all formulations and doses.
Dizziness	0–2% FDA label dose-stratified withdrawal data	Rarely associated with treatment withdrawal per the integrated FDA dataset.

Management Priority — Nitrate Headache

Headache occurs in nearly half of patients on standard ER doses and is the principal reason patients abandon nitrate therapy. Practical strategies: start at 5 mg BID (IR) or 30 mg ER and titrate upward, schedule acetaminophen 500–1000 mg with the morning dose for the first 7–14 days, and counsel that the headache reliably attenuates with continued exposure. Failure to anticipate this effect at initiation is the most common pitfall in nitrate prescribing.

Int

Drug Interactions

Because isosorbide mononitrate is metabolised by hepatic denitration and is not a CYP substrate, its interactions are almost entirely pharmacodynamic — driven by additive vasodilation or synergistic NO/cGMP signalling. The PDE5-inhibitor and soluble guanylate-cyclase-stimulator interactions are absolute contraindications and the most important to identify at every prescribing event.

Major Sildenafil, Tadalafil, Vardenafil, Avanafil

MechanismPDE5 inhibition amplifies nitrate-induced cGMP accumulation in vascular smooth muscle

EffectProfound, prolonged hypotension; reports of myocardial infarction and death

ManagementCONTRAINDICATED. Standard washouts: ≥24 h after sildenafil or vardenafil; ≥48 h after tadalafil; per FDA label, no nitrate within 24 h of sildenafil. Consult individual PDE5i product label for avanafil washout.

FDA PI / ACC-AHA Consensus

Major Riociguat (Adempas)

MechanismDirect soluble guanylate cyclase stimulation compounded by NO release

EffectSevere systemic hypotension

ManagementCONTRAINDICATED per riociguat label — no minimum washout permits safe co-administration.

Riociguat FDA PI

Major Alcohol (acute, large quantities)

MechanismAdditive vasodilation and impaired baroreflex; explicitly noted in FDA Imdur label

EffectSymptomatic hypotension, syncope, increased orthostatic light-headedness

ManagementCounsel against binge drinking; moderate intake usually tolerated once patient is stable on therapy.

FDA PI

Moderate Calcium channel blockers

MechanismAdditive vasodilation; explicitly highlighted in the FDA Imdur label

EffectMarked symptomatic orthostatic hypotension

ManagementStagger initiations; reduce dose of either class if needed; monitor postural BP at every titration.

FDA PI

Moderate Other antihypertensives (ACEi, ARB, diuretics, alpha-blockers)

MechanismAdditive systemic blood pressure lowering

EffectOrthostatic hypotension, especially at initiation or dose escalation of either agent

ManagementCheck supine and standing BP after any change; reduce alpha-blocker dose if symptomatic.

Lexicomp

Moderate Tricyclic antidepressants, phenothiazines

MechanismAlpha-adrenergic blockade compounds nitrate venodilation; anticholinergic dryness may impair sublingual nitrate absorption

EffectOrthostatic hypotension; reduced rescue-nitrate efficacy

ManagementMonitor postural BP; use the lowest effective antianginal dose.

Micromedex

Moderate Dihydroergotamine

MechanismNitrates may increase DHE bioavailability; DHE causes coronary vasoconstriction antagonising the antianginal effect

EffectAntagonism of antianginal effect or DHE toxicity

ManagementAvoid combination; choose triptan or non-ergot migraine therapy.

Lexicomp

Minor Cholesterol assays (Zlatkis-Zak)

MechanismPer FDA label, nitrates and nitrites interfere with the Zlatkis-Zak colorimetric reaction

EffectFalsely low serum cholesterol determinations

ManagementModern enzymatic cholesterol assays are unaffected; document nitrate use if the laboratory still uses Zlatkis-Zak.

FDA PI

Mon

Monitoring

Isosorbide mononitrate requires no laboratory surveillance — monitoring is exclusively clinical and centred on symptom control, hemodynamic tolerance, and the recognition of nitrate tolerance.

Blood pressure (supine & standing) Baseline, at each titration, then 6-monthly
Routine Postural drop >20/10 mmHg with symptoms warrants dose reduction. Particular vigilance in elderly patients and those on multiple antihypertensives.
Heart rate Baseline, then with each clinic visit
Routine Resting tachycardia >100 bpm may indicate excessive nitrate-induced reflex sympathetic activation; consider beta-blocker addition if not already prescribed.
Anginal frequency & severity Every visit; patient diary encouraged
Routine Loss of efficacy after initial response strongly suggests tolerance from inadequate nitrate-free interval. Re-confirm dosing schedule before escalating dose.
Headache severity First 2 weeks, then at each visit
Routine Anticipatory counselling is the most effective monitoring intervention. Provide acetaminophen guidance at initiation.
Concomitant PDE5i / riociguat use Every encounter
Routine Ask explicitly about over-the-counter or social-source PDE5 inhibitors at every visit and during emergency department triage.
Methemoglobin level Only on clinical suspicion
Trigger-based Cyanosis unresponsive to oxygen, chocolate-brown blood, or saturation gap between SpO₂ and PaO₂ — order co-oximetry. Per FDA label, methemoglobinemia at therapeutic ISMN doses is essentially absent and is a feature of overdose.
Tolerance assessment If efficacy declines
Trigger-based Verify the nitrate-free interval is at least 10–14 hours. If correctly dosed and still ineffective, consider switching antianginal class rather than escalating ISMN.

Contraindications & Cautions

Absolute Contraindications

Hypersensitivity to organic nitrates or any tablet excipient (the only contraindication explicitly named in the FDA Imdur label).
Concurrent PDE5 inhibitors — sildenafil, tadalafil, vardenafil, avanafil — per FDA-mandated class labelling for both nitrate and PDE5i products.
Concurrent riociguat — per riociguat FDA label.

Relative Contraindications (Specialist Input Recommended)

Hypertrophic obstructive cardiomyopathy (HOCM) — preload reduction worsens left ventricular outflow tract obstruction and may precipitate syncope (FDA label warning); cardiologist co-management essential.
Severe aortic stenosis — nitrates may compromise coronary perfusion in fixed-output states; use only with valve assessment and specialist involvement.
Right ventricular myocardial infarction — RV-dependent preload makes patients exquisitely sensitive to nitrate-induced hypotension.
Constrictive pericarditis or cardiac tamponade — fixed cardiac output cannot compensate for venodilation.
Acute myocardial infarction or acute heart failure — per FDA Imdur label, ISMN is not recommended in these settings because its hemodynamic effects are difficult to terminate rapidly.
Severe hypotension or marked volume depletion — correct before initiation; even small doses may produce severe hypotension per the FDA label.
Increased intracranial pressure — nitrate-induced cerebral vasodilation may aggravate ICP.

Use with Caution

Elderly patients — start at the lowest dose; orthostatic hypotension and falls risk per FDA label.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency — relevant chiefly because methylene blue (the antidote for methemoglobinemia, though that complication is rare with ISMN) is contraindicated in G6PD deficiency.
Severe anaemia — although not a labelled contraindication for ISMN specifically, theoretical concerns about methemoglobin formation worsening already-compromised oxygen delivery.
Pregnancy — reserve for clear maternal benefit (former Pregnancy Category B; no signal of teratogenicity in animals but inadequate human data).

FDA Class-Wide Regulatory Warning Nitrate–PDE5 Inhibitor Co-Administration

The FDA Imdur label and the FDA labels of all PDE5 inhibitors carry an absolute contraindication against concomitant use. Co-administration can produce profound and prolonged hypotension that has resulted in myocardial infarction and death. Clinicians must actively screen at every encounter — including chest-pain triage in the emergency department — for over-the-counter or social-source sildenafil, tadalafil, vardenafil, or avanafil before administering any nitrate (including sublingual nitroglycerin) to a patient already on ISMN.

Standard washout intervals: ≥24 hours after sildenafil or vardenafil; ≥48 hours after tadalafil; consult the avanafil product label. No safe washout interval is established for riociguat, which is a separate absolute contraindication.

Patient Counselling

Purpose of Therapy

Explain that isosorbide mononitrate is taken every day to prevent chest pain from coronary disease, not to relieve an attack that has already started. Patients should continue to carry sublingual nitroglycerin for breakthrough symptoms and should know that the daily tablet is a long-term partnership with the heart, not a rescue medication.

How to Take

For the once-daily extended-release tablet, take it with water in the morning. Tablet-handling rules per the FDA label: 60 mg ER tablets are scored and may be split if a half dose is prescribed; 30 mg ER tablets must not be broken; 120 mg ER tablets are not scored and are swallowed whole. Do not crush or chew any extended-release tablet. For twice-daily immediate-release tablets, take both doses in the first part of the day (commonly 8 a.m. and 3 p.m.) so that the body has a long medication-free period overnight; this gap is essential for the medicine to keep working and is not optional. Do not stop the tablet abruptly without medical advice — the protective effect is lost and chest pain can rebound.

Headache During the First Two Weeks

Tell patient Headache is the most common effect, particularly in the first 7–14 days, and tends to settle as the body adjusts. Acetaminophen taken with the morning dose helps. Pushing through this early phase is worthwhile because the headache fades while the heart-protective benefit remains.

Call prescriber If headache is severe, lasts longer than two weeks, is associated with vomiting, or arrives suddenly with vision changes — call the same day rather than waiting.

Dizziness on Standing

Tell patient Stand up slowly from sitting and lying positions, particularly first thing in the morning and after the dose peak. Sit down at the first sign of light-headedness. Stay well hydrated and avoid hot showers in the hour after taking the tablet.

Call prescriber Fainting, falls, persistent dizziness through the day, or palpitations that do not settle within minutes warrant prompt review.

Erectile Dysfunction Treatments & Recreational PDE5 Use

Tell patient Tablets such as sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra), and avanafil (Stendra) — including any obtained without a prescription — must never be taken with this medication. The combination can cause a dangerous, sometimes fatal drop in blood pressure. Inform every doctor, dentist, and pharmacist that you are on a nitrate before starting any new prescription or supplement.

Call prescriber If you have already taken a PDE5 inhibitor in the last 24–48 hours, call before taking your nitrate dose or attend an emergency department for assessment.

Chest Pain While on Therapy

Tell patient Continue your daily tablet as prescribed. For an acute episode, sit down, place a sublingual nitroglycerin tablet or spray under the tongue, and wait five minutes. If the pain persists after the second dose, call emergency services — do not delay.

Call prescriber If chest pain becomes more frequent, lasts longer, occurs at rest, or wakes you from sleep, contact your prescriber within 24 hours; urgent reassessment is required.

Alcohol & Lifestyle

Tell patient Heavy or rapid alcohol intake can drop blood pressure further; modest amounts with food are usually well tolerated once you are settled on the dose. Continue regular activity — exercise tolerance often improves on therapy.

Call prescriber If you experience repeated near-faints after alcohol or exertion, your dose or schedule may need adjustment.

Missed or Doubled Doses

Tell patient If you forget the morning dose and remember within a few hours, take it. If it is already late in the day, skip it and resume the schedule tomorrow — never double up to make up. Taking the dose late in the evening will defeat the medication-free interval and reduce its protective effect.

Call prescriber If you accidentally take two doses close together and develop a severe headache, dizziness, or fainting — seek medical care.

Ref

Sources

Regulatory (PI / SmPC)

U.S. Food and Drug Administration. Imdur® (isosorbide mononitrate) extended-release tablets — full prescribing information (Schering Corporation / Kremers Urban Pharmaceuticals; revised December 2010). drugs.com/pro/imdur.html Definitive U.S. label for once-daily ER ISMN; the source for adverse-event incidence rates (headache 38–57%, dizziness 8–11%) and the 8% overall discontinuation figure cited in this monograph.
U.S. Food and Drug Administration. Monoket® (isosorbide mononitrate) immediate-release tablets — full prescribing information. reference.medscape.com Source for the immediate-release product, including the asymmetric 7-hour twice-daily schedule (5–20 mg BID).
UK Electronic Medicines Compendium. Imdur 60 mg modified-release tablets — Summary of Product Characteristics. medicines.org.uk/emc/product/875/smpc European labelling source for additional adverse-event frequencies (hypotension 4–5%, loss of appetite 2.5%, nausea 1%) not enumerated in the FDA label.

Key Clinical Trials

Thadani U, Maranda CR, Amsterdam E, et al. Lack of pharmacologic tolerance and rebound angina pectoris during twice-daily therapy with isosorbide-5-mononitrate. Ann Intern Med. 1994;120(5):353–359. doi.org/10.7326/0003-4819-120-5-199403010-00001 Foundational evidence establishing the asymmetric 8 a.m./3 p.m. IR ISMN dosing strategy that prevents tolerance.
Chrysant SG, Glasser SP, Bittar N, et al. Efficacy and safety of extended-release isosorbide mononitrate for stable effort angina pectoris. Am J Cardiol. 1993;72(17):1249–1256. doi.org/10.1016/0002-9149(93)90292-K Pivotal once-daily ER ISMN trial (n = 313) supporting the Imdur licensing application; demonstrated sustained 12-hour antianginal effect at 120 and 240 mg doses without tolerance development.
Taylor AL, Ziesche S, Yancy C, et al. Combination of isosorbide dinitrate and hydralazine in blacks with heart failure (A-HeFT). N Engl J Med. 2004;351(20):2049–2057. doi.org/10.1056/NEJMoa042934 Mortality benefit of nitrate-plus-hydralazine in self-identified Black HFrEF patients — note the trial used isosorbide dinitrate, not mononitrate, although ISMN is sometimes substituted in practice.
ISIS-4 Collaborative Group. ISIS-4: a randomised factorial trial assessing early oral captopril, oral mononitrate, and intravenous magnesium sulphate in 58,050 patients with suspected acute myocardial infarction. Lancet. 1995;345(8951):669–685. doi.org/10.1016/S0140-6736(95)90865-X Largest trial of routine oral mononitrate in acute MI — neutral mortality result that bounded the role of ISMN in acute coronary syndromes.

Guidelines

Virani SS, Newby LK, Arnold SV, et al. 2023 AHA/ACC/ACCP/ASPC/NLA/PCNA guideline for the management of patients with chronic coronary disease. Circulation. 2023;148(9):e9–e119. doi.org/10.1161/CIR.0000000000001168 Current U.S. guideline positioning long-acting nitrates as add-on antianginal therapy in chronic coronary syndromes.
Knuuti J, Wijns W, Saraste A, et al. 2019 ESC guidelines for the diagnosis and management of chronic coronary syndromes. Eur Heart J. 2020;41(3):407–477. doi.org/10.1093/eurheartj/ehz425 European framework for nitrate use in stable angina, including tolerance management.
Heidenreich PA, Bozkurt B, Aguilar D, et al. 2022 AHA/ACC/HFSA guideline for the management of heart failure. Circulation. 2022;145(18):e895–e1032. doi.org/10.1161/CIR.0000000000001063 HFrEF guideline endorsing the hydralazine-plus-nitrate combination in self-identified Black patients (Class I).

Mechanistic / Basic Science

Münzel T, Daiber A, Gori T. Nitrate therapy: new aspects concerning molecular action and tolerance. Circulation. 2011;123(19):2132–2144. doi.org/10.1161/CIRCULATIONAHA.110.981407 Authoritative review of organic nitrate biotransformation, NO release, and the molecular basis of tolerance.
Ignarro LJ, Buga GM, Wood KS, Byrns RE, Chaudhuri G. Endothelium-derived relaxing factor produced and released from artery and vein is nitric oxide. Proc Natl Acad Sci USA. 1987;84(24):9265–9269. doi.org/10.1073/pnas.84.24.9265 Identification of NO as the molecular mediator linking nitrate pharmacology to vasodilation.

Pharmacokinetics / Special Populations

Abshagen U, Spörl-Radun S. First data on effects and pharmacokinetics of isosorbide-5-mononitrate in normal man. Eur J Clin Pharmacol. 1981;19(6):423–429. doi.org/10.1007/BF00548586 Original dose-response study establishing oral threshold (5 mg), maximum effective single dose (20–30 mg), and the dose-related side-effect profile of ISMN in healthy volunteers.
Abshagen U, Betzien G, Endele R, Kaufmann B. Pharmacokinetics of intravenous and oral isosorbide-5-mononitrate. Eur J Clin Pharmacol. 1981;20(4):269–275. doi.org/10.1007/BF00618777 Definitive PK characterisation establishing complete oral absorption with no first-pass metabolism, ~0.6 L/kg distribution volume, and ~5-hour terminal half-life.
Cheitlin MD, Hutter AM Jr, Brindis RG, et al. Use of sildenafil (Viagra) in patients with cardiovascular disease — ACC/AHA expert consensus document. J Am Coll Cardiol. 1999;33(1):273–282. doi.org/10.1016/S0735-1097(98)00656-1 Foundational consensus that codified the absolute contraindication between organic nitrates and PDE5 inhibitors.