HydrALAZINE Hydrochloride(hye dral’ a zeen)
Apo-Hydralazine (CAN), Apresoline
PREGNANCY CATEGORY C
Drug Classes
Antihypertensive
Vasodilator (peripheral)
Therapeutic Actions
Acts directly on vascular smooth muscle to cause vasodilation, primarily arteriolar, decreasing peripheral resistance; maintains or increases renal and cerebral blood flow.
Indications
Oral: Essential hypertension alone or in combination with other drugs
Parenteral: Severe essential hypertension when drug cannot be given orally or when need to lower BP is urgent
Contraindications and Cautions
Contraindicated with hypersensitivity to hydralazine, tartrazine (in 100-mg tablets marketed as Apresoline); CAD, mitral valvular rheumatic heart disease (implicated in MI).
Use cautiously with stroke; increased intracranial pressure (drug-induced BP decrease increases risk of cerebral ischemia); severe hypertension with uremia; advanced renal damage; slow acetylators (higher plasma levels may be achieved; lower dosage may be adequate); lactation, pregnancy, pulmonary hypertension.
Available Forms
Tablets—10, 25, 50, 100 mg; injection—20 mg/mL
Dosages
Adults
Oral
Initiate therapy with gradually increasing dosages. Start with 10 mg qid PO for the first 2–4 days; increase to 25 mg qid PO for the first week. Second and subsequent weeks: 50 mg qid. For maintenance, adjust to lowest effective dosage; twice-daily dosage may be adequate. Some patients may require up to 300 mg/day. Incidence of toxic reactions, particularly the lupus-like syndrome, is high in patients receiving large doses.
Parenteral
Hypertension: Patient should be hospitalized. Give IV or IM. Use parenteral therapy only when drug cannot be given orally. Usual dose is 20–40 mg, repeated as necessary. Monitor BP frequently; average maximal decrease occurs in 10–80 min. Transfer to oral form as soon as possible.
Eclampsia: 5–10 mg every 20 min via IV bolus; if no response after 20 mg, try another drug.
Pediatric patients
Although safety and efficacy have not been established by controlled clinical trials, hydralazine has been used in children.
Oral
0.75 mg/kg/day PO, given in divided doses every 6 hr. Dosage may be gradually increased over the next 3–4 wk to a maximum of 7.5 mg/kg/day PO in four divided doses or 200 mg/day PO.
Parenteral
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