hydralazine hydrochloride

CLINICAL USE

Vasodilator antihypertensive agent

DOSE IN NORMAL RENAL FUNCTION

Oral: Hypertension: 25–50 mg twice daily; —maximum daily dose 100 mg in women and slow acetylators, 200 mg in fast acetylatorsHeart failure: 25–75 mg 3–4 times daily —IV: slow IV injection: 5–10 mg over 20 minutes; repeat after 20–30 minutes if necessaryInfusion: 200–300 micrograms/minute initially, reducing to 50–150 micrograms/minute

PHARMACOKINETICS

  • Molecular weight                           :196.6
  • %Protein binding                           :87
  • %Excreted unchanged in urine     : 2–14
  • Volume of distribution (L/kg)       :0.5–0.9
  • half-life – normal/ESRD (hrs)      :2–4/16

    DOSE IN RENAL IMPAIRMENT

    GFR (mL/MIN)

  • 20 to 50     : Start at low dose and adjust in accordance with response
  • 10 to 20     : Start at low dose and adjust in accordance with response
  • <10           : Start at low dose and adjust in accordance with response

    DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

  • CAPD                :Not dialysed. Dose as in GFR <10 mL/min
  • HD                     :Not dialysed. Dose as in GFR <10 mL/min
  • HDF/high flux   :Not dialysed. Dose as in GFR <10 mL/min
  • CAV/VVHD      :Not dialysed. Dose as in GFR=10–20 mL/min

    IMPORTANT DRUG INTERACTIONS

    Potentially hazardous interactions with other drugs

  • Anaesthetics: increased hypotensive effects

    ADMINISTRATION

    Reconstition

    20 mg with 1 mL water for injection then dilute with 10 mL sodium chloride 0.9% for IV injection or 500 mL sodium chloride 0.9% for

    IV infusion

    Route

    Oral, IV peripherally

    Rate of Administration

    As above

    Comments

    Minimum volume of 60 mg in 60 mL.

    OTHER INFORMATION

    Avoid long-term use in severe renal insufficiency and dialysis patients, due to accumulation of metaboliteshydralazine hydrochloride.

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