Isosorbide in Pregnancy and Breastfeeding

Risk Factor: CM
Class: Diuretics

Contents of this page:
Fetal Risk Summary
Breast Feeding Summary
Questions and Answers

Fetal Risk Summary

Isosorbide is a nitric oxide donor, similar to nitroglycerin, that is used in the management of angina pectoris and of heart failure. It is administered sublingually, chewable tablets, and oral tablets. An oral spray is also available outside of the United States. The molecular weight (about 236) is low enough that passage to the fetus should be expected.

The drug produces dose-related embryotoxicity in rabbits at doses 35 and 150 times the maximum recommended human dose (1). (See also Nitroglycerin or Amyl Nitrite).

Two full reports and one abstract have described the use of isosorbide dinitrate during human pregnancy (2,3 and 4). However, all of the pregnancies in these reports had prescheduled elective terminations for nonmedical reasons shortly after the drug exposure. In a 1996 study (first published as an abstract in 1995), 18 women in the 2nd trimester received a single 5-mg sublingual dose of isosorbide dinitrate (2,3). Statistically significant decreases in the maternal systolic and diastolic blood pressures were observed 6 minutes after the dose. The blood pressures gradually returned to control levels over the ensuing 30 minutes. The mean maternal heart rate significantly increased from about 85 beats/minute to 96 beats/minute at 6 minutes, but declined to near control levels at 8 minutes. The mean systolic-diastolic flow velocity ratios in the umbilical and uterine arteries declined significantly, reaching nadirs at 6 and 10 minutes, respectively, before gradually returning to pre-dose levels. These findings suggested that isosorbide dinitrate may be beneficial in reversing the effects of endothelial cell dysfunction-induced generalized vasoconstriction and increased vascular resistance to flow in the uteroplacental circulation, such as occurs in preeclampsia (2,3).

In a similar investigation by these same researchers, 11 women at a mean gestational age of 10.0 weeks (range 8.211.6 weeks) were given a single 5-mg sublingual dose of the drug (4). The results of this study were comparable to the researchers previous work and led them to a similar conclusion that isosorbide dinitrate may be effective in reversing the effects of the endothelial cell dysfunction that is observed in preeclampsia (4).

Breast Feeding Summary

No reports describing the use of isosorbide dinitrate during lactation have been located. The molecular weight (about 236) is low enough that excretion into breast milk should be expected. The effects of this exposure on a nursing infant are unknown.


  1. Product information. Isordil. Wyeth-Ayerst Laboratories, 1993.
  2. Thaler I, Amit A, Itskovitz J. The effect of isosorbide dinitrate, a nitric oxide donor, on human uterine and placental vascular resistance in patients with preeclampsia (abstract). Am J Obstet Gynecol 1995;172:387.
  3. Thaler I, Amit A, Jakobi P, Itskovitz-Eldor J. The effect of isosorbide dinitrate on uterine artery and umbilical artery flow velocity waveforms at mid-pregnancy. Obstet Gynecol 1996;88:83843.
  4. Amit A, Thaler I, Paz Y, Itskovity-Eldor J. The effect of a nitric oxide donor on Doppler flow velocity waveforms in the uterine artery during the first trimester of pregnancy. Ultrasound Obstet Gynecol 1998;11:948.

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Questions and Answers

Why does isosorbide dinitrate and hydralazine work in treating congestive heart failure in african americans?, Results from the African-American Heart Failure Trial suggested a strong improvement. I just want to know whether there are any biological justifications found.

Seems all very muddy at this stage but there are some findings....

Firstly in 2001, the prevalence of HF was 40% more common in black males than white males (3.5% vs 2.3%) and twice as common in black females as white females (3.1% vs 1.5%).

In this debate, one issue that is commonly confused is the difference between race and ancestry. Ancestry refers to objective genetic relationships between individuals and among populations, whereas race has always been a somewhat arbitrary definition of population boundaries. For example, while an individual might have ancestors from Europe, Africa, and North America, he or she still might be categorized as an African American. Therefore, race captures some biological information about ancestry, but it is not equivalent to ancestry.

Yet clinicians often want to know whether it is valid and reliable to use race as a proxy to infer an individual's genetic risk for disease and treatment response. Whether race matters is, however, complicated because it depends on the relationship between the genetic risk factor, ancestry, and race. For example, beta-blockers and angiotensin-converting enzyme (ACE) inhibitors for hypertension treatment may not work as well, on average, in African Americans compared with European Americans, but both types of drugs appear to work perfectly well in a large fraction of African Americans and poorly in some European Americans.

The observation might be explained by a hypothetical genetic predictor of positive response to ACE inhibitors that is common in European Americans but that is also present in some African Americans because of admixture and absent in some European Americans. In such a case, the best predictor of treatment response might be the presence of the variant (ie, direct testing); the next best might be an accurate estimator of genetic ancestry, and race might be only a poor predictor of genetic risk and therefore treatment response.

What can happen if you overdose on isosorbide mn?, i consumed about 360mg all together thinking that it was painkiller, now the symptoms are my ankle area hurts very bad and this morning i had very bad headache and trouble breathing i recover from that but ankle are killing me, will it go away? soon. i am young healthy 22 years old. no health problem at all. PLEASE HELP THANKS.

As mentioned above, isosorbide monititrate is a type of nitrate. This class of drugs is commonly used to treat heart disease. They work by causing blood vessels to expand. Headache is a common side effect. Too much nitrates may cause low blood pressure, dizziness, and chest pain. Unfortunately, there are different formulations of isosorbide mononitrtate, and you may have taken an extended release form.

I suggest you contact your local poison control for more information or 1-800-POISONS. They will be better able to instruct you on warning signs after accidental overdose and proper treatment. If your symptoms worsen, call 911.

I take 20mg Isosorbide my doctor received a letter from the hospital?, Consultant to double the dose to morning and evening why? my own doc does not like one asking questions.

I assume that you have been recently admitted to the hospital and your consultant has sent a letter to your GP to increase the dose of your isosorbide. I am just wondering if you have received such instruction or letter from the hospital or the nurse who has discharged you. You should have one or just a verbal instruction about your medications.

Isosorbide is given to patients with angina. I am just wondering if you have been having unstable anginas lately thus assuming why your dosage was increased.

I am a nurse and I really don't like making assumptions here. I want you to ask your consultant or your GP. You have the right to ask questions and to be aware of your own treatment. It is very silly for a doctor who does not like you asking questions. If that was my doctor, I will definitely switch and look for a better one.

How to take isosorbide dinitrate?,

your doctor must have said two to three times a day. oral pill, good luck

isosorbide mononit possible side effect?, my wife just started taking the drug isosorbide mononit and she is seeing brite strips of light out the corners of her eyes? is this harmful or will the symptoms go away?

The pain of coronary heart disease (angina) usually occurs when the heart requires more blood and oxygen than its blood vessels supplying the heart can deliver. The demand for oxygen can be reduced and pain prevented in one of two ways. First, by dilating the veins and allowing more blood to "pool." This reduces the amount of blood returning to the heart and hence the heart's work and need for oxygen. Second, by dilating the arteries of the body and reducing the pressure within the arteries. This reduces the pressure that the heart has to pump against and hence the Heart's work and need for oxygen. Isosorbide mononitrate reduces angina by dilating both the veins and the arteries.

Isosorbide mononitrate also increases supply of oxygen to the heart by dilating the arteries which supply the heart itself. Isosorbide mononitrate is in the class of drugs called anti-anginal medications. Isosorbide mononitrate is the chief metabolite of isosorbide dinitrate, and most of the activity of isosorbide dinitrate is due to its metabolite, isosorbide mononitrate.

Since isosorbide mononitrate can cause hypotension (low blood pressure), other medications which can reduce blood pressure may produce additive effects causing serious drops in blood pressure. Such drugs might include those used to treat high blood pressure, some antidepressants; some anti-psychotics, quinidine, procainamide, benzodiazepines such as diazepam (Valium) or opiates (e.g. morphine).

Since ethanol also may intensify the blood pressure lowering effect of isosorbide mononitrate, patients receiving isosorbide mononitrate should be advised to use ethanol with caution.

I would certainly report these symptoms to her physcian. It could be a harmless side effect, but it needs to be reported.

Exactly what is Isosorbide Mononitrate used for?, The cardiologist said every thing looked normal on the different tests so why this medication plus have nitro pills on hand

Isosorbide mononitrate reduces angina by dilating both the veins and the arteries.

Isosorbide mononitrate also increases supply of oxygen to the heart by dilating the arteries which supply the heart itself. Isosorbide mononitrate is in the class of drugs called anti-anginal medications.

Is is correct that ISOSORBIDE DINITRATE USP advesely affects a man's sexual abilities? Pl. help.?, I've also heard that over a longer period of its intake it also 'shrinks' the penis in size?


same message as this morning isosorbide mononit side affects any one on them?,

In my book it would appear to be headaches, flushes and dizziness.
I am not taking them personally but the book I have lists this as an anti anginal. Hope this helps.e

what is isosorbide dinitrate (isoket spray) ?,

It is used for angina (chest pain). Isosorbide dinitrate works by releasing a chemical called nitric oxide. This chemical is also made naturally by the body and has the effect of making the veins and arteries relax and widen (dilate). This increases the space within the blood vessels and therefore reduces the resistance within the blood vessels, which makes it easier for the heart to pump blood around the body.