hydralazine (Apresoline)
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Introduction
Tradename: Apresoline.
Indications
- hypertension, especially in combination with a diuretic
- useful in treatment of regurgitant valvular lesions
- in combination with nitrates, hydralazine enhances survival in patients with heart failure
- obstetrics:
- agent of choice in eclampsia
- long history of use in obstetrics
- it appears to be harmless to the fetus
Contraindications
- recent cerebral hemorrhage
- dissecting aortic aneurysm
- not first line treatment of hypertension in pregnant women due to reflex tachycardia & fluid retention (edema)[7]
Caution:
- hydralazine increases myocardial oxygen consumption, making this drug unfavorable for most hypertensive emergencies
Dosage
- IV infusion 0.2-0.5 mg/min
- IV bolus 10 mg every 3-4 hours
- 20-40 mg IV/IM every 4-6 hours
- oral
Tabs: 10, 25 50, 100 mg.
Pharmacokinetics
- onset of action
- oral bioavailability is variable
- 35% for slow acetylators
- 16% for rapid acetylators
- 87% is bound to plasma proteins
- metabolized by the liver to multiple metabolites
- 1-15% of drug is excreted unchanged into the urine
elimination via liver
elimination via kidney
1/2life = 2-5 hours
Adverse effects
- common (> 10%)
- less common (1-10%)
- constipation, hypotension, redness or flushing of the face, dyspnea, lacrimation, nasal congestion
- uncommon (< 1%)
- dizziness, edema, malaise, peripheral neuritis, fever, rash, arthralgias, weakness, positive ANA & positive LE cells (lupus-like syndrome)
- other
Tolerance: may occur, but may be reduced by concomitant diuretic use
Drug interactions
- metoprolol & propranolol increase levels of hydralazine & visa versa (via decrease in 1st pass metabolism)
- NSAIDs may decrease antihypertensive effects of hydralazine
- drug interaction(s) of beta-adrenergic receptor antagonists with hydralazine
- drug interaction(s) of NSAIDs & antihypertensives
Mechanism of action
- direct arterial vasodilating agent
- produces direct relaxation of arteriolar smooth muscle
- effect is greater on arterioles than on veins
- reduces afterload
- may cause reflex tachycardia
More general terms
Component of
- hydralazine/hydrochlorothiazide; hydralazine/HCTZ (Apresazide)
- hydralazine/hydrochlorothiazide/reserpine; hydralazine/HCTZ/reserpine (Ser Ap Es)
- hydralazine/isosorbide dinitrate (BiDiL)
References
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 118.
- ↑ AHFS Drug Information, American Society of Health-System Pharmacists, Bethesda, 1998
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ 5.0 5.1 Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- ↑ 6.0 6.1 Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 476
- ↑ 7.0 7.1 7.2 Medical Knowledge Self Assessment Program (MKSAP) 19. American College of Physicians, Philadelphia 2021