May 4, 2016
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Side Effects


Clinical Trials Experience

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.

BiDil has been evaluated for safety in 517 heart failure patients in A-HeFT. A total of 317 of these patients received BiDil for at least 6 months, and 220 received BiDil for at least 12 months. In A-HeFT, 21% of the patients discontinued BiDil for adverse reactions compared to 12% who discontinued placebo. Overall, adverse reactions were more common in BiDil -treated than in placebo-treated patients. Table 1 lists adverse reactions reported with an incidence, after rounding, ≥ 2% higher on BiDil than on placebo in A-HeFT, regardless of causality. The most common reasons for discontinuing BiDil in the A-HeFT trial was headache (7%).

Table 1: Adverse Reactions Occurring in the A-HeFT Study in ≥ 2% of Patients Treated with BiDil

(N=517) %
(N=527) %
Headache 50 21
Dizziness 32 14
Asthenia 14 11
Nausea 10 6
Hypotension 8 4
Sinusitis 4 2
Ventricular tachycardia 4 2
Paresthesia 4 2
Vomiting 4 2
Amblyopia 3 1

In the V-HeFT I and II clinical studies, a total of 587 patients with heart failure were treated with the combination of isosorbide dinitrate and hydralazine hydrochloride. The type, pattern, frequency and severity of adverse reactions reported in these studies were similar to those reported in A-HeFT, described above and no unusual adverse reactions were reported.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of BiDil. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Use of BiDil: The following adverse reactions have been identified with use of BiDil.

Cardiac Disorders: Palpitations
Ear and labyrinth disorders:
Tinnitus, vertigo
Eye Disorders:
Eyelid edema, vision blurred
Gastrointestinal Disorders:
Abdominal discomfort, constipation
General Disorders and Administration Site Conditions:
Facial pain, flushing, chest discomfort, chest pain, peripheral edema
Musculoskeletal and Connective Tissue Disorders:
Pain in extremity, myalgia
Nervous Disorders:
Dysgeusia, hypoaesthesia, migraine, syncope
Renal and Urinary Disorders:
Chromaturia, pulmonary renal syndrome
Respiratory, Thoracic and Mediastinal Disorders:
Reproductive System and Breast Disorders:
Erectile dysfunction
Skin and Subcutaneous Tissue Disorders:
Erythema, hyperhidrosis, pruritus, face swelling

Use of Hydralazine Hydrochloride or Isosorbide Dinitrate: The following reactions have been reported with use of either hydralazine hydrochloride or isosorbide dinitrate.

Blood and Lymphatic System Disorders: Blood dyscrasias, agranulocytosis, purpura, eosinophilia, splenomegaly.
Eye Disorders:
Lacrimation, conjunctivitis.
Gastrointestinal Disorders:
Paralytic ileus.
Hepatobiliary Disorders:
Psychiatric Disorders:
Psychotic reactions, disorientation.
Renal and Urinary Disorders:
Difficulty in urination.

Read the BiDil (isosorbide dinitrate and hydralazine hcl) Side Effects Center for a complete guide to possible side effects


Phosphodiesterase Inhibitors

BiDil is contraindicated in patients who are using a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), PDE5 inhibitors such as avanafil, sildenafil, vardenafil, and tadalafil have been shown to potentiate the hypotensive effects of organic nitrates. Do not use BiDil in patients who are taking the soluble guanylate cyclase (sGC) stimulator riociguat. Comcomitant use can cause hypotension [see CONTRAINDICATIONS].

Read the BiDil Drug Interactions Center for a complete guide to possible interactions

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 4/21/2015

Side Effects

BiDil - User Reviews

BiDil User Reviews

Now you can gain knowledge and insight about a drug treatment with Patient Discussions.

Here is a collection of user reviews for the medication BiDil sorted by most helpful. Patient Discussions FAQs

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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