出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2013/10/14 23:44:53」(JST)
Systematic (IUPAC) name | |
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1-hydrazinylphthalazine | |
Clinical data | |
AHFS/Drugs.com | monograph |
MedlinePlus | a682246 |
Pregnancy cat. | C Commonly used to treat severe PIH |
Legal status | ? |
Routes | Oral, intravenous |
Pharmacokinetic data | |
Bioavailability | 26-55% |
Metabolism | Hepatic |
Half-life | 2-4 hours |
Excretion | Renal |
Identifiers | |
CAS number | 86-54-4 Y |
ATC code | C02DB02 |
PubChem | CID 3637 |
DrugBank | DB01275 |
ChemSpider | 3511 Y |
UNII | 26NAK24LS8 Y |
KEGG | D08044 Y |
ChEBI | CHEBI:5775 Y |
ChEMBL | CHEMBL276832 Y |
Chemical data | |
Formula | C8H8N4 |
Mol. mass | 160.176 g/mol |
SMILES
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InChI
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Y (what is this?) (verify) |
Hydralazine (apresoline) is a 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 and decreasing afterload.[1]
However, this only has a short term effect on blood pressure, as the system will reset to the previous, high blood pressure necessary to maintain pressure in the kidney necessary for natriuresis. The long term effect of antihypertensive drugs comes from their effects on the pressure natriuresis curve.
It belongs to the hydrazinophthalazine class of drugs.[2]
Hydralazine increases cyclic guanosine monophosphate (cGMP) levels, increasing the activity of protein kinase G (PKG). Active PKG adds an inhibitory phosphate to myosin light-chain kinase (MLCK) – a protein involved in the activation of cross-bridge cycling (i.e. contraction) in smooth muscle. This results in blood vessel relaxation. It dilates arterioles more than veins.[3]
Hydralazine requires the endothelium to provide NO (nitric oxide.[4] ) thus only provides the effects of NO in vivo with functional endothelium. It will not work to vasodilate in vitro in an isolated blood vessel.
Activation of hypoxia-inducible factors has been suggested as a mechanism.[5]
Hydralazine is not used as a primary drug for treating hypertension because it elicits a reflex sympathetic stimulation of the heart (the baroreceptor reflex). The sympathetic stimulation may increase heart rate and cardiac output, and in patients with coronary artery disease may cause angina pectoris or myocardial infarction.[1] Hydralazine may also increase plasma renin concentration, resulting in fluid retention. In order to prevent these undesirable side-effects, hydralazine is usually prescribed in combination with a beta-blocker (e.g., propranolol) and a diuretic.[1] In the UK, labetalol tends to be the first line beta-blocker.
Hydralazine is used to treat severe hypertension, but again, it is not a first-line therapy for essential hypertension. However, hydralazine is the first-line therapy for hypertension in pregnancy, with methyldopa.[6]
Multiple sclerosis: Due to its ability to damage myelin nerve sheaths, acrolein may be a factor in the development of multiple sclerosis. Hydralazine, a known scavenger of acrolein, was found to reduce myelin damage and significantly improve behavioral outcomes in a mouse model of multiple sclerosis (experimental autoimmune encephalomyelitis).[7]
Common side-effects include:
Patients given hydralazine over a period of six months may develop a lupus-like syndrome or other immune-related diseases that, in general, are reversible with withdrawal.[1] Hydralazine is differentially acetylated by fast and slow acetylator phenotypes, hence incidence of lupus-like disease in slow acetylators.[citation needed] Rarely, hydrazaline may cause Dyscrasia typically manifested as a type of leukopenia. As such, your physician may request you undergo regular Complete blood count tests. Template:Cite package insert
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リンク元 | 「ヒドララジン」 |
関連記事 | 「hydrochloride」 |
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