Bidil (isosorbide dinitrate/hydralazine HCl)

When hydralazine therapy is discontinued in patients with a marked reduction in blood pressure, withdrawal should be gradual to avoid a possible sudden increase in blood pressure. One study found 20-25 mg of IV hydralazine hydrochloride approximately equal to 75-100 mg of oral hydralazine hydrochloride.

Dosage of isosorbide dinitrate and isosorbide mononitrate must be carefully adjusted according to the patient's requirements and response and the smallest effective dosage should be used.

When isosorbide dinitrate is used in fixed combination with hydralazine, the cautions, precautions, and contraindications associated with hydralazine must be considered in addition to those associated with isosorbide dinitrate (see Cautions and Precautions and Contraindications in the Nitrates and Nitrites General Statement 24:12.08).

Clinical studies of isosorbide dinitrate alone or in fixed combination with hydralazine did not include sufficient numbers of patients 65 years of age and older to determine whether geriatric patients respond differently than younger patients. Although other clinical experience has not revealed age-related differences in response or tolerance, drug dosage generally should be titrated carefully in geriatric patients, usually initiating therapy at the low end of the dosage range. The greater frequency of decreased hepatic, renal, and/or cardiac function and of concomitant disease and drug therapy observed in the elderly also should be considered. Elimination of isosorbide dinitrate and its metabolites may occur more slowly in geriatric patients than in younger adults.

Clinical studies of isosorbide mononitrate did not include sufficient numbers of patients 65 years of age and older to determine whether geriatric patients respond differently than younger patients. Other clinical experience has not identified any differences in responses between geriatric and younger patients. One manufacturer of isosorbide mononitrate states that if isosorbide mononitrate is used in geriatric patients, dosage of the drug should be selected with caution, usually initiating therapy at the low end of the dosage range, although age, renal, hepatic, and cardiovascular dysfunction do not appear to have a significant effect on the clearance of the drug.

Patients with severe renal failure may require a lower dosage of hydralazine.

Hydralazine hydrochloride usually is administered orally. In patients who are unable to take the drug orally or when a rapid decrease in blood pressure is required, the drug may be given IM or IV. Oral therapy with hydralazine should replace parenteral therapy as soon as possible.

No dosing information is available for this tab.

No dosing information is available for this tab.

There is no enhanced messaging for this drug.

There are no contraindication interactions for this drug.

There are no severe interactions for this drug.

There are no moderate interactions for this drug.

There is no enhanced messaging for this drug.

There are no contraindication contraindications for this drug.

There are no severe contraindications for this drug.

There are no moderate contraindications for this drug.

There is no enhanced messaging for this drug.

There are no severe adverse reactions for this drug.

There are no less severe adverse reactions for this drug.

No enhanced messaging available.

No enhanced messaging available.

Safe use of hydralazine in pregnancy has not been established. Hydralazine is teratogenic in mice and possibly in rabbits but not in rats. Teratogenic effects in animals have included cleft palate and malformation of facial and cranial bones.

A meta-analysis of randomized, controlled trials comparing hydralazine with other antihypertensive agents for the treatment of severe hypertension during pregnancy showed that hydralazine was associated with a higher incidence of maternal hypotension, placental abruption, cesarean sections, and oliguria, as well as a higher incidence of lower Apgar scores and adverse effects on fetal heart rate than the other hypotensive drugs. In one study in 13 pregnant women with long-standing hypertension during 15 pregnancies who received combination therapy with hydralazine and propranolol, 14 live births and one unexplained stillbirth were reported. The only neonatal complications observed were 2 cases of mild hypoglycemia. In patients receiving hydralazine during pregnancy, the drug and its metabolites have been detected in maternal and umbilical plasma using a nonselective assay. The manufacturers state that although clinical experience with the drug does not indicate any positive evidence of adverse effect on the human fetus to date, hydralazine should not be used during pregnancy unless the possible benefits outweigh the potential risks to the fetus.

It is not known whether hydralazine is distributed into breast milk. Because many drugs are distributed into milk, the drug should be used with caution in nursing women.

No enhanced messaging available.