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hydralazine (Rx)Brand and Other Names:

 
 
 

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

injectable solution

  • 20mg/mL

tablets

  • 10mg
  • 25mg
  • 50mg
  • 100mg
more...

Severe Essential Hypertension

10 mg PO q6hr for 2-4 days; 25 mg q6hr daily for the first week; increase to 50 mg q6hr from second week on; adjust dose to lowest effective levels

20-40 mg IM/IV; repeat as necessary

Dosing considerations

  • Change to oral therapy as soon as possible

Hypertension (Chronic)

Initial: 10 mg PO q6hr for 2-4 days; may increase gradually by 10-25 mg/dose every 2-5 days up to 50 mg PO q6hr (some patients require 300 mg/day)

See also combo with isosorbide dinitrate

Hypertensive Crisis

20-40 mg IV/IM; repeat PRN

Pregnancy-associated

  • 5-10 mg IV/IM initially, THEN 5-10 mg q20-30min PRN, OR
  • 0.5-10 mg/hr IV infusion

Congestive Heart Failure

Initial dose: 10-25 mg q6-8hr PO

Maintenance dose: 225-300 mg/day divided q6-8hr PO

Dosing considerations

  • Adjust dose per individual response

Dosage Forms & Strengths

injectable solution

  • 20mg/mL

tablets

  • 10mg
  • 25mg
  • 50mg
  • 100mg
more...

Severe Essential Hypertension

1.7-3.5 mg/kg/day IM or IV divided in 4-6 doses. 

Hypertensive Crisis

3 months - 1 year: 0.1-0.5 mg/kd/dose IV q6-8hr; not to excced 2 mg/kg IV q6hr; titrate dose for blood pressure control

>1 year: 0.1-0.2 mg/kg IV/IM q4-6hr PRN initially; may increase to usual dose of 1.7-3.5 mg/kg/day divided q4-6hr; not to exceed 20 mg/dose IM or IV or 2 mg/kg q3-6hr with cumulative dose not to exceed 9 mg/kg 

Hypertension (Chronic)

Initial: 0.75-1 mg/kg/day PO divided q6-12hr 

Maximum dose in infants (<1 year): 5 mg/kg/day PO divided q6-12hr, 20 mg/dose, or 200 mg/day

Maximum dose in children (>1 year): 7.5 mg/kg/day PO divided q6hr; not to exceed 200 mg/day

Increase gradually over 3-4 weeks

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Interactions

Interaction Checker

hydralazine and

No Results

     
     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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            Adverse Effects

            Frequency Not Defined

            Hypotension

            Palpitations

            Conjunctivitis

            Tachycardia

            Headache

            Peripheral edema

            Vascular collapse

            Peripheral neuropathy

            Anorexia

            Diarrhea

            Nausea

            Vomiting

            Psychotic reaction

            Agranulocytosis

            Leukopenia

            Hepatotoxicity

            Chest pain

            Dyspnea

            Nasal congestion

            Paralytic ileus

            Dysurea

            Thrombocytopenia

            Peripheral neuritis

            Rheumatoid arthritis

            Agranulocytosis

            Arthralgia

            SLE syndrome

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            Warnings

            Contraindications

            Hypersensitivity to hydralazine

            Coronary artery disease

            Mitral valve rheumatic heart disease

            Cautions

            May induce SLE-type syndrome (usually at >200 mg/day); instruct patients to report joint/chest pain or fever; consider discontinuation if occurs

            Use caution in CVA, severe renal impairment, volume depletion, preexisting hypotension, concurrency with other hypotensive agents, CAD (potential contraindication)

            Discontinue slowly to avoid rapid rise in blood pressure

            Use with caution in patients with pulmonary hypertension; may cause hypotension

            Increases fluid and sodium retention; may require treatment or increase in diutretic dose

            Peripheral neuritis reported; treat symptoms with pyridoxine

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            Pregnancy & Lactation

            Pregnancy category: C

            Lactation: Excreted in breast milk; use caution

            Pregnancy Categories

            A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA:Information not available.

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            Pharmacology

            Mechanism of Action

            Direct vasodilator; dilates arterioles with little effect on vein; decreases systemic resistance, which subsequently decreases blood pressure.

            Absorption

            Bioavailability: Slow acetylator: 30-50%; rapid acetylator: 22-30%

            Onset: 5-20 min, maximum effect 10-80 min (IV); 20-30 min (PO)

            Duration: 3-8 hr (PO); 1-4 hr (IV)

            Distribution

            Protein bound: 85-90%

            Vd: 0.3-8.2 L/kg

            Metabolism

            Significantly metabolized in liver by acetylation; slow and rapid acetylator

            Metabolites: Phthalazine and pyruvic acid hydrazone metabolites (inactive metabolite)

            Elimination

            Half-life: 2-8 hr (normal renal function); 7-16 hr (end-stage renal disease)

            Excretion: Urine (14%; unchanged)

            Pharmacogenomics

            HLA-DRw4 appears in 73% of patients experiencing hydralazine-associated SLE

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            Administration

            IV Incompatibilities

            Solution: D5W, D10/LR, fructose 10%, fructose 10%/NS

            Additive: Aminophylline, ampicillin, chlorothiazide, dobutamine, CaNa2EDTA, ethacrynate, hydrocortisone sodium succinate, mephentermine, methohexital, nitroglycerin, phenobarbital, verapamil

            Y-site: Aminophylline, ampicillin, diazoxide, furosemide

            IV Compatibilities

            Solution: Dextrose-Ringer combinations, D5/LR, dextrose 2.5%/½LR, dextrose-saline combinations, D10W, Ringer, LR, ½NS, NS, Na-lactate 1/6M

            Y-site: Heparin, hydrocortisone sodium succinate, nitroglycerin (compatible for 3 hr; may form slight ppt), KCl, verapamil, vit B/C

            IV Preparation

            Prepare immediately before use

            Minimize contact with metal parts during preparation and administration

            IV/IM Administration

            Administer IM or as rapid IV injection directly into vein

            Avoid adding drug to infusion solution

            Storage

            Store at controlled room temp

            Do not refrigerate

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            Images

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            Formulary

            FormularyPatient Discounts

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            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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