- Molecular NameHydralazine
- SynonymHydralazine hydrochloride
- Weight160.18
- Drugbank_IDDB01275
- ACS_NO86-54-4
- Show 3D model
- LogP (experiment)1.0
- LogP (predicted, AB/LogP v2.0)1.16
- pka0.5, 7.1
- LogD (pH=7, predicted)0.65
- Solubility (experiment)Soluble
- LogS (predicted, ACD/Labs)(ph=7)-0.94
- LogSw (predicted, AB/LogsW2.0)0.54
- Sw (mg/ml) (predicted, ACD/Labs)17.36
- No.of HBond Donors3
- No.of HBond Acceptors4
- No.of Rotatable Bonds1
- TPSA63.83
- StatusFDA approved
- AdministrationOral, intravenous
- PharmacologyA direct-acting smooth muscle relaxant used to treat hypertension by acting as a vasodilator primarily in arteries and arterioles. By relaxing vascular smooth muscle, vasodilators act to decrease peripheral resistance, thereby lowering blood pressure.
- Absorption_value100.0
- Absorption (description)Readily absorbed after oral administration.
- Caco_2N/A
- Bioavailability23.0
- Protein binding87.0
- Volume of distribution (VD)3 to 8 L/kg
- Blood/Plasma Partitioning ratio (D_blood)N/A
- MetabollsmIt undergoes first-pass acetylation, the extent of which is genetically determined. The major metabolites are: 3-methyl-1,2,4-triazolo[3,4-a]phthalazine (MTP—the acetylation product); hydralazine pyruvic acid hydrazone (HPH) which is the major plasma metabolite; 4-(2-acetylhydrazino)phthalazin-1-one (N-AcHPZ) which is the major urinary metabolite; 3-hydroxymethyl-1,2,4-triazolo[3,4-a]phthalazine (3-OHMTP).
- Half lifehydralazine 0.4~2 h, HPH about 4 h, MTP about 1.5~2 h
- ExcretionAbout 65% of a dose is excreted in the urine in 24 h. In rapid acetylators, about 30% is excreted as N-AcHPZ and 10 to 30% as conjugated 3-OHMTP; in slow acetylators, about 15 to 20% is excreted as N-AcHPZ and up to 10% as conjugated 3-OHMTP. Other metabolites include phthalazin-1-one (PZ), 1,2,4-triazolo[3,4-a]phthalazine (TP), 9-hydroxy-MTP, phthalazine, tetrazolo[5,1-a]phthalazine and hydrazones of hydralazine formed with acetone and α-ketoglutaric acid. About 10% of a dose is eliminated in the faeces.
- Urinary ExcretionN/A
- CleranceN/A
- ToxicityThe most common adverse events reported in clinical trial studies are headache, anorexia, nausea, vomiting, diarrhea, palpitations, tachycardia, angina pectoris.
- LD50 (rat)N/A
- LD50 (mouse)N/A