Isosorbide Dinitrate/Mononitrate

Class: Nitrates and Nitrites
VA Class: CV250
Chemical Name: d-Glucitol-1,4:3,6-dianhydrodinitrate
Molecular Formula: C₆H₈N₂O₈C₆H₉NO₆
CAS Number: 87-33-2
Brands: BiDil, Dilatrate, Imdur, Ismo, Isordil, Monoket

Introduction

Isosorbide dinitrate and isosorbide mononitrate: Organic nitrates; vasodilating agents.

Uses for Isosorbide Dinitrate/Mononitrate

Angina

Isosorbide dinitrate or mononitrate is used for the acute relief of angina pectoris, for prophylactic management in situations likely to provoke angina attacks, and for long-term prophylactic management of angina pectoris.^b

Conventional measures in the management of angina pectoris are aimed at reducing the frequency, duration, and severity of attacks, and include coronary risk reduction (e.g., discontinuance of smoking, weight control, antilipemic strategies), rest, avoidance of precipitating circumstances (e.g., eating heavy meals, getting emotionally upset, performing strenuous exercise, exposure to cold air) and, if possible, treatment of the underlying cause.^c

β-Adrenergic blocking agents generally are considered among the initial antianginal drugs of choice in the long-term prophylactic management of chronic stable angina with or without prior MI to reduce symptoms and to prevent MI and/or death.^{258 c}

Isosorbide dinitrate or mononitrate can be used alone or in combination as either second-line or third-line therapy in patients previously treated with a β-adrenergic blocking agent.²⁵⁸

Prolonged use of oral nitrates has been associated with the development of tolerance to the hemodynamic and antianginal effects and possibly with cross-tolerance to sublingual nitrates. (See Tolerance and Dependence under Cautions.)

Generally considered for monotherapy in the prophylactic management of angina pectoris only when β-adrenergic blocking agents or calcium-channel blocking agents are contraindicated, associated with unacceptable adverse effects, or are ineffective.²⁵⁸

If a β-adrenergic blocking agent is not effective in controlling chronic stable angina, long-acting nitrates may be added to β-blocker therapy.²⁵⁸

CHF: Fixed-combination Therapy with Hydralazine in Self-identified Black Patients

In fixed combination with hydralazine as adjunct to standard therapy for the treatment of CHF in self-identified black patients to improve survival, decrease rate of hospitalization for worsened heart failure, and improve patient-reported functional status.^{336 337 338}

CHF: Other Therapies in the General Population

Isosorbide dinitrate (in combination with cardiac glycosides and diuretics or with hydralazine) effective for the treatment of CHF† or other low cardiac output states†.^b

Concomitant therapy with isosorbide dinitrate and hydralazine may decrease mortality in patients with CHF; usually reserved for patients who fail to respond to or are intolerant of first-line therapy (e.g., ACE inhibitors) or in combination with such therapy.^{c 255 257}

Do not use isosorbide dinitrate as monotherapy for CHF.^c

Diffuse Esophageal Spasm

Isosorbide dinitrate has been used effectively for diffuse esophageal spasm† without gastroesophageal reflux to relieve pain, dysphagia, and spasm.^b

Isosorbide Dinitrate/Mononitrate Dosage and Administration

Administration

Isosorbide Dinitrate

Administer sublingually, intrabuccally, or orally.^b

Sublingual or intrabuccal nitrates may be inadequately absorbed, with resultant decreased efficacy, in patients with dry oral mucous membranes (e.g., xerostomia).^{219 220}

Do not chew extended-release preparations.^b

The patient should be sitting immediately after sublingual or intrabuccal administration.^b

Isosorbide Mononitrate

Administer orally.^{290 291 292}

Extended-release tablets can be administered as whole or halved tablets, but swallow intact and do not chew or crush.²⁹²

Administer extended-release tablets with adequate amounts of fluid (e.g., 120 mL) on arising in the morning.²⁹²

Dosage

Adjust dosage of isosorbide dinitrate and isosorbide mononitrate carefully according to the patient’s requirements and response; use the smallest effective dosage.^b

Although many clinicians do not gradually reduce the dosage when discontinuance of oral nitrates is planned, it appears prudent that dosage be gradually reduced (e.g., over a period of about 1–2 weeks) to avoid withdrawal manifestations.^c Supplementary sublingual nitroglycerin doses should be given if necessary during dosage reduction.³⁰²

Adults

Angina

Acute Symptomatic Relief and Prophylactic Management

Do not use extended-release isosorbide dinitrate preparations or any isosorbide mononitrate preparation to abort an acute anginal episode or for acute relief of angina or in the prophylactic management in situations likely to provoke angina attacks; onset is not sufficiently rapid.^{224 290 291 292}

Sublingual

Patients who fail to respond to nitroglycerin lingual or sublingual: 2.5–5 mg of isosorbide dinitrate.^b

If relief is not attained after a single dose during an acute attack, may give additional doses at 5- to 10-minute intervals; give no more than 3 doses in a 15- to 30-minute period.^b

Prophylactic management in situations likely to provoke angina attacks in patients who fail to respond to sublingual nitroglycerin: place 2.5–5 mg of isosorbide dinitrate under the tongue about 15 minutes prior to engaging in such activities.²⁰⁰

Intrabuccal

Patients who fail to respond to nitroglycerin lingual or sublingual: 2.5–5 mg of isosorbide dinitrate.^b

If relief is not attained after a single dose during an acute attack, may give additional doses at 5- to 10-minute intervals; no more than 3 doses should be given in a 15- to 30-minute period.^b

Prophylactic management in situations likely to provoke angina attacks in patients who fail to respond to sublingual nitroglycerin: 2.5–5 mg of isosorbide dinitrate should be placed under the tongue approximately 15 minutes prior to engaging in such activities.²⁰⁰

Long-term Prophylactic Management

Oral (Isosorbide Dinitrate Conventional Tablets)

Initially, isosorbide dinitrate conventional tablets (e.g., Isordil Titradose) 5–20 mg administered 2–3 times daily, followed by maintenance dosage of 10–40 mg administered 2–3 times daily (some patients may require higher dosages).^{302 b}

Suggested schedules: Usually, at 7 a.m., 12 p.m., and 5 p.m. in chronic stable angina or at 7 a.m. and 12 p.m. in less severely symptomatic angina in order to allow for a nitrate-free interval of 10–14 hours.^{302 b}

May need to adjust schedule for those arising earlier than 7 a.m. since early morning angina is common.³²⁴

Less frequent administration of isosorbide dinitrate may reduce the development of tolerance to the drug’s antianginal effects.^{b c}

Oral (Isosorbide Dinitrate Extended-release Capsules)

An interdosing interval sufficient to avoid tolerance to Dilatrate-SR extended-release capsules is not known, but it must exceed 18 hours.²²⁴

Do not exceed daily Dilatrate-SR dosages of 160 mg (4 capsules).²²⁴

Oral (Isosorbide Mononitrate Conventional Tablets)

Usual initial dosage of conventional tablets (e.g., Monoket): 20 mg twice daily, with the 2 doses administered 7 hours apart.^{290 291}

Particularly small stature, initially: 5 mg (½ of a 10-mg tablet) twice daily, for no longer than initial 2 days.²⁹¹

Particularly small stature, maintenance: Increased to at least 10 mg twice daily by the second or third day.²⁹¹

Oral (Isosorbide Mononitrate Extended-release Tablets)

Initially, (e.g., Imdur): 30 mg (as a single 30-mg tablet or as ½ of a 60-mg tablet) or 60 mg (as a single 60-mg tablet) once daily.²⁹²

May increase dosage to 120 mg (as a single 120-mg tablet or as two 60-mg tablets) once daily after several days; 240-mg dosages rarely needed.²⁹²

CHF

Fixed-combination Therapy with Hydralazine in Self-identified Black Patients

Oral (Isosorbide Dinitrate in Fixed Combination with Hydralazine Hydrochloride Tablets)

Initially, isosorbide dinitrate 20 mg and hydralazine hydrochloride 37.5 mg (1 tablet of BiDil) 3 times daily.³³⁶ May titrate dosage to a maximum tolerated dosage not to exceed 2 tablets (a total of 40 mg of isosorbide dinitrate and 75 mg of hydralazine hydrochloride) 3 times daily.³³⁶ Rapid titration (over 3–5 days) may be possible; however, slower titration may be needed due to adverse effects.³³⁶ May decrease dosage to as little as ½ of the fixed-combination tablet 3 times daily in patients who experience intolerable effects, but attempt to titrate dosage up once adverse effects subside.³³⁶

Other Therapies in the General Population†

Oral (Isosorbide Dinitrate Conventional Tablets)

Initially, 80 mg of isosorbide dinitrate (administered as ½ of a 40 mg conventional tablet 4 times daily) daily in combination with oral dosages of 150 mg of hydralazine hydrochloride (as a single 37.5 mg tablet 4 times daily) daily for 2 weeks.²⁵⁶

If initial dosages are tolerated, increase daily dosages to 160 mg of isosorbide dinitrate and 300 mg of hydralazine hydrochloride.²⁵⁶

Diffuse Esophageal Spasm

Oral (Isosorbide Dinitrate Conventional Tablets)

10–30 mg 4 times daily.^b

Prescribing Limits

Adults

Angina

Acute Symptomatic Relief and Prophylactic Management

Sublingual

No more than 3 doses in a 15- to 30-minute period.^b

Intrabuccal

No more than 3 doses in a 15- to 30-minute period.^b

Long-term Prophylactic Management

Oral (Isosorbide Dinitrate Extended-release Capsules)

Maximum daily dosage of Dilatrate-SR: 160 mg (4 capsules).²²⁴

Oral (Isosorbide Mononitrate Extended-release Tablets)

Dosages of 240 mg are rarely needed.²⁹²

CHF

Fixed-combination Therapy with Hydralazine Hydrochloride in Self-identified Black Patients

Oral (Isosorbide Dinitrate in Fixed Combination with Hydralazine Hydrochloride Tablets)

Maximum 40 mg of isosorbide dinitrate and 75 mg of hydralazine hydrochloride (2 tablets of BiDil) 3 times daily.³³⁶

Special Populations

Hepatic Impairment

No specific dosage recommendations for hepatic impairment.^b

Renal Impairment

No specific dosage recommendations for renal impairment.^b

Geriatric Patients

One manufacturer of isosorbide mononitrate states that dosage should be selected with caution, usually initiating therapy at the low end of the range, although age, renal, hepatic, and cardiovascular dysfunction do not appear to have a significant effect on drug clearance.³²⁵

The manufacturer of the fixed combination of isosorbide dinitrate and hydralazine hydrochloride states that dosage should be selected with caution because of age-related decreases in hepatic, renal, and/or cardiac function and concomitant disease and drug therapy.³³⁶

Cautions for Isosorbide Dinitrate/Mononitrate

Contraindications

• 
  

  Known hypersensitivity to isosorbide or any ingredient in the respective formulation.³⁰²

  
  


• 
  

  Manufacturers state that selective phosphodiesterase (PDE) inhibitors (e.g., sildenafil, tadalafil, vardenafil) are contraindicated in patients receiving nitrates.^c Complete avoidance may not be possible, provided sufficient time elapses between use of the drugs.^c (See Phosphodieterase Inhibitors under Cautions).

  
  


• 
  

  Extended-release oral nitrate preparations should not be used in patients with functional or organic GI hypermotility or malabsorption syndrome.^c

  
  


• 
  

  Isosorbide dinitrate is contraindicated in patients with shock or marked low blood pressure.^c

  
  

Warnings/Precautions

Warnings

Selective Phosphodiesterase (PDE) Inhibitors

Selective PDE inhibitors can potentiate the hypotensive effects of organic nitrates and nitrites, possibly resulting in potentially life-threatening hypotension and/or hemodynamic compromise.^c

Manufacturers of selective PDE inhibitors (e.g., sildenafil, tadalafil, vardenafil) state that the drugs are contraindicated in patients receiving organic nitrates or nitrites in any form (e.g., orally, sublingually, transmucosally, parenterally), given regularly or intermittently,²⁶² or nitric oxide donors since severe, potentially fatal hypotensive episodes can occur.^{260 261 262 263 266 271 272 282 284 285 288}

Clinicians unfamiliar with their patients’ drug history, especially those involved in emergency care (e.g., for presumed myocardial infarction or ischemia), should take a careful history so that concomitant use of organic nitrates or nitrites with selective PDE inhibitors can be avoided.^{260 264 271}

Warn all patients receiving organic nitrates or nitrites about the potential interaction between the drugs and selective PDE inhibitors, even if they currently are not receiving the drugs, since there is substantial potential for patients to receive the drugs from another clinician, from a friend, with little or no clinical intervention (e.g., via the Internet),²⁸¹ or illicitly.^{260 281 282}

Warn all patients taking either selective PDE inhibitors or organic nitrates or nitrites of the potential consequences of taking the drugs within close proximity (e.g., within 24 hours of sildenafil; possibly more prolonged periods of risk with longer-acting PDE inhibitors) of taking a nitrate- or nitrite-containing preparation.^{260 282}

Cardiovascular Effects

Severe hypotension, particularly in upright position, can occur even with low doses.³⁰²

Caution in volume depletion or preeexisting hypotension.³⁰²

Paradoxical bradycardia and angina exacerbation may accompany hypotension.³⁰²

Benefits in AMI and CHF not established.³⁰²

Careful clinical or hemodynamic monitoring for possible hypotension or tachycardia if used in AMI or CHF.³⁰²

Avoid long-acting dosage forms in the early management of AMI or CHF since the effects are difficult to terminate rapidly should excessive hypotension or tachycardia occur.^c

Sensitivity Reactions

Occur extremely rarely.³⁰²

General Precautions

Tolerance and Dependence

Tolerance to the vascular and antianginal effects of individual nitrates and cross-tolerance among the drugs may occur with repeated, prolonged use.^c

Carefully individualize nitrate dosage to minimize the risk of tolerance; also consider potential risks of nitrate withdrawal.^c

Employ intermittent dosing of nitrates (e.g., use of a nitrate-free interval of 10–12 hours daily) to minimize or prevent the development of tolerance to the hemodynamic and antianginal effects of the drugs.^c

Possibility of an increased frequency or severity of angina during the nitrate-free interval should be considered.^c

Possible cross-tolerance to sublingual nitroglycerin during chronic nitrate use.^c

Nitrate dependence is possible (documented in daily industrial exposures); withdrawal manifestations (e.g., ischemic symptoms, MI, sudden death) can occur.^c

Use of Fixed Combinations

When isosorbide dinitrate is used in fixed combination with hydralazine, consider the cautions, precautions, and contraindications associated with hydralazine.³³⁶

Specific Populations

Pregnancy

Category C.^pdh

Lactation

Not known whether isosorbide dinitrate and isosorbide mononitrate are distributed into milk.^{200 224 290 291 292 302} Caution if used in nursing women.³⁰²

Geriatric Use

Not known whether geriatric patients respond differently than younger patients.^{325 336} (See Geriatric Patients under Dosage.)

Common Adverse Effects

Serious adverse reactions to the organic nitrates and nitrites are uncommon and their adverse effects mainly involve the CNS and cardiovascular system.

Headache, the most frequent adverse effect, may be severe (persistent or transient) and is perceived as a pulsating, throbbing sensation; frequent early in therapy, usually diminishes rapidly, and may disappear within several days to weeks of continuous therapy.^c Aspirin or acetaminophen may relieve.^c

Postural hypotension may occur and may cause dizziness, weakness, and other signs of cerebral ischemia.

Transient flushing may occur with the nitrates, and inhalation of amyl nitrite commonly causes cutaneous flushing of the head, neck, and clavicular area.

May cause a burning or tingling sensation when administered sublingually.

May cause blurred vision and should be discontinued if this symptom occurs.

Interactions for Isosorbide Dinitrate/Mononitrate

Specific Drugs or Laboratory Tests

Drug or Test	Interaction	Comments
Alcohol	Concomitant use may cause hypotensionc	Use concomitantly with cautionc
Antihypertensive drugs	Possible additive hypotensive effectsc	Dosage adjustment of either the nitrate/nitrite or the other agent with hypotensive activity may be necessary to avoid orthostatic hypotension during concomitant usec
Disopyramide	Disopyramide may reduce the efficacy of isosorbide dinitrate294 Antimuscarinic actions of disopyramide may decrease salivary secretions and thereby inhibit the dissolution of the sublingual tablets294	Use concomitantly with caution
Ergot alkaloids (dihydroergotamine)	Dihydroergotamine may counteract the coronary vasodilatory effect of nitrates303 316	Use concomitantly with caution; risk of angina precipitation
Nitrites	Patients receiving nitrates or nitrites concomitantly should be observed for possible additive hypotensive effectsc	Dosage adjustment of either the nitrate/nitrite or the other agent with hypotensive activity may be necessary to avoid orthostatic hypotension during concomitant usec
Phenothiazines	Possible additive hypotensive effectsc	Use concomitantly with caution; may need to adjust dosage to avoid orthostatic hypotension c
Phosphodiesterase (PDE) inhibitors, selective	Sildenafil and other selective PDE inhibitors (e.g., tadalafil, vardenafil) profoundly potentiate the vasodilatory effects (e.g., a >25-mm Hg decrease in SBP) of organic nitrates and nitrites (e.g., nitroglycerin, isosorbide dinitrate), and potentially life-threatening hypotension and/or hemodynamic compromise can result259 260 261 262 263 264 266 271 272 274 275 282 284 285	Because of the serious risk of concurrent use of organic nitrates or nitrites and selective PDE inhibitors, such combined use is contraindicated259 260 261 262 282 287 If consideration is given to administering a nitrate or nitrite after a PDE inhibitor (e.g., >24 hours after sildenafil use), the response to the initial doses must be monitored carefully and proper facilities for fluid and vasopressor (e.g., α-adrenergic agonists) support must be readily available to prevent acute ischemic episodes260 289
Test, Zlatkis-Zak color reaction	Nitrates and nitrites may interfere with the Zlatkis-Zak color reaction causing a false report of decreased serum cholesterolc

Isosorbide Dinitrate/Mononitrate Pharmacokinetics

Absorption

Bioavailability (Isosorbide Dinitrate)

Readily (and almost completely) absorbed from the GI tract and oral mucosa, but considerable variations in the bioavailability (10–90%) secondary to extensive first-pass metabolism in the liver.^{224 294 302}

Conventional oral tablets: 25% unchanged drug; about half that following sublingual administration (40–50%).^{20 200 226 228}

Bioavailability (Isosorbide Mononitrate)

Readily absorbed from the GI tract;^{291 294 295} does not undergo first-pass hepatic metabolism.^{290 291 292 294 295 296 297 298}

Conventional tablets: Approximately 100%.^b

Extended-release tablets: Approximately 77–80%.^{290 291 292 294 295 296 297 298}

Onset and Duration

The approximate onset and duration of action of various dosage forms of isosorbide dinitrate (ISDN) and isosorbide mononitrate (ISMN) are as follows:^b

Antianginal Effects

Dosage Form	Onset	Duration
Sublingual ISDN	Within 3 min200 225	2 h200 225
Chewable ISDN	Within 3 min225	2–2.5 h225
Oral ISDN	1 h225	Up to 8 h225
Oral ISMN	1 h290 291	5–7 h290 291
Extended-release ISDN	1 h224	8 h224
Extended-release ISMN	1 h298	12 h298

Hemodynamic Effects

Dosage Form	Onset	Duration
Sublingual ISDN	Within 15–30 min	1.5–4 h
Chewable ISDN	5 min	2–3 h
Oral ISDN	Within 20–60 min	4–6 h
Oral ISMN	10–30 min314	At least 6 h314
Extended-release ISDN	Within 2 h313	Up to 12 h313
Extended-release ISMN	20–30 min314	At least 6 h314

Onset and duration of action following intrabuccal administration are probably similar to those after sublingual administration of isosorbide dinitrate.^b

Food

Isosorbide dinitrate: Food may decrease substantially mean peak plasma concentrations, yet total bioavailability does not seem to be affected.^{299 311} The effect of food on the bioavailability of isosorbide dinitrate when administered in fixed combination with hydralazine hydrochloride is not known.³³⁶

Isosorbide mononitrate: Generally, food delays the rate but not the extent of absorption (less than 10%) of conventional or extended-release tablets.^{292 295 298 299 300 301}

Plasma Concentrations

Isosorbide dinitrate – sublingual, peak: 10–15 minutes.^{200 302}

Isosorbide dinitrate – conventional tablets, peak: 60 minutes.^{200 302}

Isosorbide dinitrate – fixed-combination tablets with hydralazine hydrochloride, peak: 60 minutes.³³⁶

Isosorbide mononitrate – conventional tablets, peak: 0.5–1 hour.²⁹²

Isosorbide mononitrate – extended-release tablets, peak: 3–4.5 hours.²⁹²

Special Populations

Risk of elevated blood concentrations of isosorbide dinitrate in patients with cirrhosis.³³⁶

Distribution

Extent

Distribution into human body tissues and fluids has not been fully characterized.^{294 302 303 304}

Not known whether isosorbide dinitrate and isosorbide mononitrate are distributed into milk.^{200 224 290 291 292 302}

Plasma Protein Binding

Isosorbide dinitrate: Approximately 28%.^{290 291 292 303}

Isosorbide mononitrate: Approximately 4–5%.^{290 291 292 303}

Elimination

Metabolism

Isosorbide dinitrate: Metabolized extensively; about 15–25 and 75–85% of a dose is metabolized to isosorbide-2-mononitrate and isosorbide-5-mononitrate (referred to simply as isosorbide mononitrate), respectively; ^{200 224 290 291 292 302} both metabolites are pharmacologically active, especially isosorbide mononitrate.^{200 224 290 291 292 302}

Isosorbide dinitrate: Also probably metabolized at extrahepatic sites.^{200 224 302}

Isosorbide mononitrate: Metabolized principally in the liver, but unlike isosorbide dinitrate, does not undergo first-pass metabolism;^{290 291 292} metabolites appear to be pharmacologically inactive.^{291 292}

Elimination Route

Isosorbide dinitrate and isosorbide mononitrate are mainly excreted in the urine.^{b 291}

Half-life

Isosorbide dinitrate: About 1 hour.^{200 224 225 302}

Isosorbide dinitrate in fixed combination with hydralazine hydrochloride: About 2 hours.³³⁶

Isosorbide mononitrate: About 5 hours.^{290 291 292}

Stability

Storage

Oral (Isosorbide Dinitrate)

Tablets

Tight, light-resistant containers at room temperature (25°C); do not expose to extremes in temperature.^{b 302}

Oral (Isosorbide Mononitrate)

Tablets (Extended-release and Conventional)

Conventional tablets (e.g., Monoket): Tight, light-resistant containers at 15–30°C.^{290 292 293}

Oral (Isosorbide Dinitrate in Fixed Combination with Hydralazine Hydrochloride)

Tablets

Tight, light-resistant containers at 25°C; may be exposed to 15–30°C.³³⁶

ActionsActions

• 
  

  The exact mechanism of action in the relief of angina pectoris has not been fully elucidated.^c

  
  


• 
  

  Principal pharmacologic property is relaxation of vascular smooth muscle, resulting in generalized vasodilation.^c

  
  


• 
  

  Peripheral venous resistance is decreased via a selective action on venous capacitance vessels and results in venous pooling of blood and decreased venous return to the heart.^c

  
  


• 
  

  Vasodilatory effect on arteriolar resistance is not as great as the action on the venous side; as a result of this combined action, both venous filling pressure (preload) and, to a lesser extent, arterial impedance (afterload) are reduced.^c

  
  


• 
  

  By decreasing myocardial oxygen consumption, nitrates and nitrites alter the imbalance of myocardial oxygen supply and consumption which is thought to cause angina pectoris.^{236 250}

  
  


• 
  

  Because of their hemodynamic profile, particularly beneficial in patients with left ventricular systolic dysfunction or CHF.^{236 250}

  
  


• 
  

  Both direct vasodilatory effects on the coronary bed and drug-induced prevention of episodic coronary artery vasoconstriction increase total coronary blood flow.²³⁶

  
  


• 
  

  After therapeutic doses, cardiac output may increase transiently and then decrease.^c

  
  


• 
  

  In addition to vascular smooth muscle, nitrates and nitrites relax bronchial, biliary (including the gallbladder, biliary ducts, and sphincter of Oddi), GI (including the esophagus), ureteral, and uterine smooth muscle; nitrates relax all smooth muscle irrespective of autonomic innervation and are functional antagonists of norepinephrine, acetylcholine, and histamine.^c

  
  

Advice to Patients

• 
  

  Advise patients of the likelihood of headache, particularly with initial nitrate therapy.^c Importance of consulting clinician if headache continues with repeated dosing.³³⁶

  
  


• 
  

  Advise patients to take nitrates as directed, particularly since tolerance can occur.^c

  
  


• 
  

  Importance of instructing patients receiving isosorbide dinitrate for relief of acute attacks of angina pectoris to consult a clinician or go to a hospital emergency room immediately if chest pain is not relieved after 3 doses approximately every 5 minutes, because inability to relieve chest pain may indicate acute MI.^c

  
  


• 
  

  Importance of informing patients receiving isosorbide dinitrate in fixed combination with hydralazine that inadequate fluid intake or excessive fluid loss due to diarrhea, vomiting, or perspiration may result in excessive hypotension, possibly leading to lightheadedness or syncope; if syncope occurs, discontinue treatment and notify clinician immediately.³³⁶

  
  


• 
  

  Importance of clinicians unfamiliar with their patients’ drug history, especially those involved in emergency care (e.g., for presumed myocardial infarction or ischemia), to take a careful history so that concomitant use with selective PDE inhibitors can be avoided.^{260 264 271}

  
  


• 
  

  Importance of warning all patients receiving organic nitrates or nitrites about the potential interaction between the drugs and selective PDE inhibitors, even if they currently are not receiving the drugs, since there is substantial potential for patients to receive the drugs from another clinician, from a friend, with little or no clinical intervention (e.g., via the Internet),²⁸¹ or illicitly.^{260 281 282}

  
  


• 
  

  Importance of warning all patients taking either selective PDE inhibitors or organic nitrates or nitrites of the potentially severe and life-threatening hemodynamic consequences of taking the drugs within close proximity (e.g., within 24 hours of sildenafil; possibly more prolonged periods of risk with longer-acting PDE inhibitors) of taking a nitrate- or nitrite-containing preparation.^{260 282}

  
  


• 
  

  Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs as well as any concomitant illnesses.

  
  


• 
  

  Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.

  
  


• 
  

  Importance of informing patients of other important precautionary information. (See Cautions.)

  
  

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Isosorbide Dinitrate

Routes	Dosage Forms	Strengths	Brand Names	Manufacturer
Oral	Capsules, extended-release	40 mg	Dilatrate-SR	Schwarz
	Tablets	5 mg*	Isordil Titradose (scored)	Biovail
			Isosorbide Dinitrate Tablets	Par, Sandoz, Teva, West-Ward
		10 mg*	Isosorbide Dinitrate Tablets	Par, Sandoz, Teva, West-Ward
		20 mg*	Isosorbide Dinitrate Tablets	Par, Sandoz, Teva, West-Ward
		30 mg*	Isosorbide Dinitrate Tablets	Par
		40 mg*	Isordil Titradose (scored)	Biovail
	Tablets, extended-release	40 mg*	Isosorbide Dinitrate Tablets ER	Inwood
Sublingual (Intrabuccal)	Tablets	2.5 mg*	Isosorbide Dinitrate Tablets	West-Ward
		5 mg*	Isosorbide Dinitrate Tablets	West-Ward

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Isosorbide Mononitrate

Routes	Dosage Forms	Strengths	Brand Names	Manufacturer
Oral	Tablets	10 mg*	Isosorbide Mononitrate Tablets	Actavis, Kremers Urban
			Monoket (scored)	Schwarz
		20 mg*	Isosorbide Mononitrate Tablets	Actavis, Kremers Urban, West-Ward
			Monoket (scored)	Schwarz
	Tablets, extended-release	30 mg*	Imdur (scored)	Schering-Plough
			Isosorbide Mononitrate Tablets ER	Actavis, Ethex, Kremers Urban, Warrick
		60 mg*	Imdur (scored)	Schering-Plough
			Isosorbide Mononitrate Tablets ER	Actavis, Ethex, Kremers Urban, Warrick, West-Ward
		120 mg*	Imdur	Schering-Plough
			Isosorbide Mononitrate Tablets ER	Ethex, Kremers Urban, Warrick
	Tablets, extended-release, film-coated	20 mg	Ismo (with povidone)	ESP Pharma

Isosorbide Dinitrate Combinations

Routes	Dosage Forms	Strengths	Brand Names	Manufacturer
Oral	Tablets, film-coated	20 mg with Hydralazine Hydrochloride 37.5 mg	BiDil (scored)	NitroMed

Comparative Pricing

This pricing information is subject to change at the sole discretion of DS Pharmacy. This pricing information was updated 03/2011. Actual costs to patients will vary depending on the use of specific retail or mail-order locations and health insurance copays.

Imdur 30MG 24-hr Tablets (SCHERING): 30/$86.09 or 90/$243.54

Imdur 60MG 24-hr Tablets (SCHERING): 30/$89.99 or 90/$255.98

Isosorbide Mononitrate 10MG Tablets (KREMERS URBAN): 60/$25.99 or 180/$55.97

Isosorbide Mononitrate 20MG Tablets (ACTAVIS ELIZABETH): 60/$19.99 or 180/$48.99

Isosorbide Mononitrate CR 30MG 24-hr Tablets (WEST-WARD): 30/$20.99 or 90/$45.97

Isosorbide Mononitrate CR 60MG 24-hr Tablets (KREMERS URBAN): 30/$19.99 or 60/$29.98

Monoket 10MG Tablets (SCHWARZ PHARMA): 60/$101.99 or 180/$289.96

Monoket 20MG Tablets (SCHWARZ PHARMA): 60/$171.99 or 180/$485.97

Disclaimer

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. and Drugs.com represent that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. and Drugs.com make no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. and Drugs.com do not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS Drug Information. © Copyright, 1959-2011, Selected Revisions June 2006. American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland 20814.

† Use is not currently included in the labeling approved by the US Food and Drug Administration.

References

Only references cited for selected revisions after 1984 are available electronically.

20. Assinder DF, Chasseaud LF, Taylor T. Plasma isosorbide dinitrate concentrations in human subjects after administration of standardizing and sustained-release formulations. J Pharm Sci. 1977; 66:775-8. [PubMed 577507]

102. Whitworth CG, Grant WM. Use of nitrate and nitrite vasodilators by glaucomatous patients. Arch Ophthalmol. 1964; 71:492-6. [PubMed 14109031]

103. Zah K. Vliv nitroglyceriner na krevni obeh u sitnici: X pokuane farmakologicka studie. Cesk Ofthalmol. 1957; 13:146-9.

104. Peczon JD, Grant WM, Lambert BW. Systemic vasodilators, intraocular pressure, and chamber depth in glaucoma. Am J Ophthalmol. 1971; 72:74-8. [PubMed 5571214]

200. Wyeth Laboratories Inc. Isordil (isosorbide dinitrate) prescribing information. In: Physicians’ desk reference. 54th ed. Montvale NJ: Medical Economics Company Inc; 2000:3260-1.

201. Parker JO, Farrell B, Lahey KA et al. Effects of intervals between doses on the development of tolerance to isosorbide dinitrate. N Engl J M