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Hydralazine and Morphine

Hydralazine

Apresoline ® Antihypertensive Agent

Indications

  • In essential and early malignant hypertension, as well as in hypertensive emergencies associated with pregnancy and in hypertension which exists or recurs after sympathectomy.
  • IV use indicated only for conditions in which drugs cannot be taken orally or when there is an urgent need to lower blood pressure.

Administration

  • For IV use: reconstitute ampoule with 1 mL of SWFI.
  • IV direct: physician or RN; blood pressure monitoring. Physician to be present for first dose. Dilute dose in 20 mL of NS and inject slowly. To avoid hypotension, injection should be stopped frequently when blood pressure is falling.
  • Chamber (preferred): blood pressure monitoring. Physician to be present for start of first dose. Dilute dose in 50 mL of NS and infuse over 15 minutes.
  • Infusion (preferred): blood pressure monitoring. Physician to be present for start of first dose. Dilute 100 mg in 500 mL to 1000 mL of NS. Give slowly and adjust rate according to the blood pressure response.
  • IM.

Potential Administration Hazards

  • Postural hypotension, circulatory collapse, dizziness, flushing.
  • Tachycardia, angina, nausea and vomiting.
  • Depression, anxiety, severe headache, neuropathy.
  • Influenza-like syndrome; rheumatoid arthritis syndrome; lupus syndrome (after lengthy use).
  • Increased cerebral ischemia in predisposed patients.

Dosage

  • Usual adult dose: 5-20 mg (up to 40 mg has been used). Repeat as needed.
  • Infusion: 0.05-0.3 mg/min.
  • Preeclampsia, eclampsia: initial dose of 5-10 mg, followed by 5-20 mg every 20-30 minutes as required or may infuse at rate of 0.5-10 mg/hr.
  • Pediatrics: 0.1 to 0.2 mg/kg (maximum 20 mg) repeated q4-6h up to 1.7 mg to 3.5 mg/kg/day or 50-100 mg/m2/day in 4 to 6 divided doses.
  • IM: 10-50 mg.

Compatibility, Stability

  • Compatible with NS, Ringer’s, RL, sodium lactate 1/6 M solutions for 24 hours.
  • Stable for 1 week at RT diluted in NS at a concentration of 0.027-0.35 mg/mL.
  • Due to slow reaction between dextrose-containing solutions and hydralazine, a yellowish colour ensues which does not alter hypotensive effects. Nevertheless, manufacturer no longer recommends a dextrose-containing solution as a diluent.

Miscellaneous

  • Fall in BP may be dramatic after IV use.
  • Contraindicated in angina pectoris because of reflex tachycardia and coronary steal.
  • 20-25 mg IV is approximately equal to 75-100 mg oral hydralazine.
  • After IV administration the effect begins within 5-20 minutes. Maximum effect seen in 10-80 minutes and lasts for 2-6 hours.
  • Effect begins within 10-30 minutes after IM administration.

References : 1, 2, 4, 82, 90, 143, 157, 323.

05-05

Morphine

Narcotic analgesic

Indications

  • Supplement to anesthesia.
  • In patients with acute pulmonary edema for its cardiovascular and anxiolytic effects.
  • Relief of moderate to severe acute and chronic pain.
  • Analgesic of choice for pain associated with myocardial infarction.
  • To decrease voluntary respiratory control in patients on respirators.

Administration

  • IV direct: physician or RN. Respiratory support. Dilute dose to 10 mL and inject very slowly, at a rate of 3 mg/min.
  • Chamber: dilute dose in 50 to 100 mL NS or D5W.
  • Infusion: Standard concentration is 1 or 2 mg/mL in D5W or NS via an infusion pump. Patients on high doses may require concentration of 10 mg/mL.
  • SC, IM.

Potential Administration Hazards

  • Respiratory depression (Antidote: naloxone) and to a lesser degree circulatory depression including orthostatic hypotension (increased incidence with rapid IV administration).
  • Bradycardia (Antidote: atropine).
  • Increased intracranial pressure.
  • Nausea, vomiting, constipation.
  • Dizziness, mental clouding, sedation.
  • Pruritus; allergic phenomena.

Dosage

  • Adults
    • IV direct: 2.5-15 mg. Doses may be repeated q2-4h prn until analgesia is achieved.
    • Chamber: 5-25 mg.
    • Infusion (cancer pain): initiate at 0.8-10 mg/hr; increase stepwise until analgesia is achieved; in severe chronic pain, maintenance doses have ranged from 0.8-80 mg/hr, although higher doses (e.g., 150 mg/hr) have occasionally been required.
    • SC, IM: 2.5-20 mg q2-6h prn.
  • Pediatrics
    • Intermittent IV: 0.05-0.2 mg/kg/dose q2-4h.
    • Infusion: 0.01-2.6 mg/kg/hr.
    • SC, IM: 0.1-0.2 mg/kg/dose q4h prn.

Compatibility, Stability

  • At concentrations of 0.04-0.4 mg/mL, stable for 7 days at RT or refrigerated diluted in D5W or NS in PVC containers.
  • At a concentration of 5 mg/mL in NS or D5W, stable for 30 days at RT in PVC containers.

Miscellaneous

  • Caution in patients with convulsive disorders, cranial injuries, respiratory insufficiency, cardiac arrhythmias, reduced blood volume and in children and elderly or debilitated patients.
  • Only morphine products formulated for epidural or intrathecal use should be administered in this manner.

References : 1, 2, 4, 9, 40, 82, 187, 190, 370.

05-05

Last updated on: April 3rd, 2020