HydrALAZINE

HydrALAZINE

Indication

• 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

Pharmacology

• 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

Side Effects

• 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

Dose

• 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

Supplied As

• 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