Comparative Pharmacology
Head-to-head clinical analysis: HYDRALAZINE versus TRANSDERM NITRO.
Peer-Reviewed Evidence
Head-to-head clinical analysis: HYDRALAZINE versus TRANSDERM NITRO.
Hydralazine vs TRANSDERM-NITRO
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Hydralazine is a direct-acting vasodilator that relaxes arteriolar smooth muscle, leading to decreased peripheral vascular resistance and blood pressure. Its exact mechanism is unclear but may involve interference with calcium movement and increased cGMP levels.
Nitroglycerin is converted to nitric oxide (NO), which activates guanylate cyclase, increasing cGMP in vascular smooth muscle, leading to vasodilation.
10-50 mg orally every 6 hours, titrate to maximum 300 mg/day; 10-20 mg intramuscularly or intravenously every 4-6 hours as needed.
Initial dose 0.2-0.4 mg/hour transdermally once daily. Titrate to 0.4-0.8 mg/hour. Maximum 0.8 mg/hour.
None Documented
None Documented
Clinical Note
moderateHydralazine + Benzydamine
"Hydralazine may decrease the antihypertensive activities of Benzydamine."
Clinical Note
moderateHydralazine + Droxicam
"Hydralazine may decrease the antihypertensive activities of Droxicam."
Clinical Note
moderateHydralazine + Loxoprofen
"Hydralazine may decrease the antihypertensive activities of Loxoprofen."
Clinical Note
moderateHydralazine + Clonixin
"Hydralazine may decrease the antihypertensive activities of Clonixin."
The terminal elimination half-life of hydralazine is approximately 2-4 hours in patients with normal renal function. However, the duration of antihypertensive effect may be longer (6-12 hours) due to tissue binding and slow release from vascular smooth muscle. In renal impairment, half-life may extend to 7-16 hours, necessitating dose adjustment.
Terminal elimination half-life is approximately 1-4 minutes after IV administration due to rapid metabolism. After transdermal application, the apparent half-life is 3-4 hours due to continued absorption from the skin depot, resulting in a prolonged clinical effect.
Hydralazine is primarily metabolized in the liver via N-acetylation and hydroxylation. Approximately 80-90% of the drug is eliminated in urine as metabolites, with less than 10% excreted unchanged. A small fraction appears in feces via biliary excretion.
Renal (primarily) and biliary; ~60-80% of the dose is excreted renally as metabolites, with <1% unchanged. Fecal excretion accounts for ~10-20%.
Category A/B
Category C
Vasodilator
Vasodilator