- treatment of hypertension - but not the drug of choice for treatment of acute hypertensive crisis, see Diazoxide
- an afterload reducing agent to treat congestive heart failure
- causes direct relaxation of smooth muscle in peripheral vasculature; coronary, cerebral, splanchnic and renal vessels are affected more than vessels in muscle or skin
- undergoes high first pass effect when given orally
- approximately 85% is protein bound
- less than 15% of a given dose is excreted unchanged in the urine; dosage adjustments do not appear to be necessary in renal failure
- an increase in heart rate and cardiac output occur after hydralazine administration. This is in response to the decrease in peripheral vascular resistance
- cardiovascular (reflex tachycardia, hypotension)
- GI (vomiting, diarrhea, irritation and bleeding)
- a lupus-like syndrome has been reported in 10-20% of adult patients
- tachyphylaxis (decrease in response) can occur with prolonged therapy
- IV: 0.1 to 0.5 mg/kg every 3 to 6 h IV push by physician only, over at least 1 minute
- dilute to at least 1 mg/mL with 0.9% NaCl when giving IV
- when changing from IV to oral therapy, an increase of up to twice the effective IV dose may be necessary
- PO: 0.2 to 1 mg/kg every 3 to 6h
- 1 mg/mL diluted solution (0.9% NaCl) for IV use, in a vial, prepared by Pharmacy. Stable for 24 hours. DO NOT REFRIGERATE.
- 1 mg/mL oral solution prepared by Pharmacy
- 20 mg/mL, 1mL ampoule - after hours use
- McEvoy G K (ed): AHFS Drug Information, American Society of Hospital Pharmacists, 1991.
- Roberts, RJ: Drug Therapy in Infants, W.B. Saunders, Toronto, 1984.
- Trissel L.A.: Handbook on Injectable Drugs, American Society of Hospital Pharmacists 1988.
- Pagliaro LA and Pagliaro AM (ed): Problems in Pediatric Drug Therapy, 1987, Drug Intelligence Publ Inc, Hamilton, Illinois.
- Parenteral Drug Administration Guidelines, St. Joseph's Health Centre, London, Ontario.
- Gomella TL (Ed): Neonatology - Management, Procedures, On-Call Problems, Diseases, Drugs, 1992, Appleton and Lange, Norwalk, Connecticut.
- Milan EM and McFeely EJ: Memory Bank for Neonatal Drugs, 1990, Williams and Wilkins, Baltimore.
- Young TE and Mangum OB: Neofax - A Manual of Drugs Used in Neonatal Care, Columbus, Ohio: Ross Laboratories, 1992.