Hydralazine
Cardiac Therapy · Antihypertensive: Vasodilator
Indications
Moderate to severe hypertension (adjunct); heart failure (with long-acting nitrate; hypertensive emergencies (including during pregnancy).
Dosage
Adults: ORAL: Hypertension: 25 mg twice daily, increased to usual max 50 mg twice daily. Heart failure: (Initiated in hospital) 25 mg 3-4 times daily, increased every 2 days if necessary; usual maintenance dose 50-75 mg 4 times daily. INJECTION: Hypertensive emergencies and hypertension with renal complications: By slow IV inj, 5-10 mg diluted with 10 mL sodium chloride 0.9%; may be repeated after 20-30 min. By IV infusion, initially 200-300 mcg/min; maintenance usually 50-150 mcg/min. Children: Not recommended.
Administration
Inject over 1 min. Hypotensive effect may be delayed and unpredictable in some patients. Reconstitution: Hydralazine should be diluted in NS for IVPB administration due to decreased stability in D5W. Stability of IVPB solution in NS is 4 days at room temperature. Compatibility: Stable in NS, D5NS, D10W, D5LR, 1/2NS, LR. Incompatible with D5W. At Y-site administration, incompatible with aminophylline, ampicillin, diazoxide, furosemide. When admixed, incompatible with aminophylline, ampicillin, chlorothiazide, edetate calcium disodium, ethacrynate, hydrocortisone sodium succinate, mephentermine, methohexital, nitroglycerin, phenobarbital, verapamil. Stability: Intact ampoules/vials should not be stored under refrigeration because of possible precipitation or crystallization.
Adverse Effects
Tachycardia, palpitation, flushing, hypotension, angina, fluid retention, gastro-intestinal disturbances; headache, dizziness; systemic lupus erythematosus-like syndrome after long-term therapy with over 100 mg daily (or less in women and in slow acetylator individuals); rarely rashes, fever, dyscrasias, peripheral neuritis, polyneuritis, paraesthesia, arthralgia, myalgia, increased lacrimation, nasal congestion, dyspnoea, agitation, anxiety, anorexia; blood disorders (including leucopenia, thrombocytopenia, haemolytic anaemia), abnormal liver function, jaundice, raised plasma creatinine, proteinuria and haematuria reported.
Risk Factor (Pregnancy/Lactation)
Pregnancy: Risk cannot be ruled out. Lactation: Caution advised or effect undetermined. Contraindications: Idiopathic systemic lupus erythematosus, severe tachycardia, high output heart failure, myocardial insufficiency due to mechanical obstruction, cor pulmonale, dissecting aortic aneurysm; acute porphyria. Precautions: Coronary artery disease (may provoke angina, avoid after myocardial infarction until stabilized), cerebrovascular disease; occasionally blood pressure reduction too rapid even with low parenteral doses; manufacturer advises test for anti-nuclear factor and for proteinuria every 6 months and check acetylator status before increasing dose above 100 mg daily, but evidence of clinical value unsatisfactory. Severe renal failure ( CrCl <30mL/min), hepatic dysfunction.
Interactions
CYP3A4, beta-blockers, MAOIs, propranolol, NSAIDs, TCADs, CNS depressants, anaesthetics, antihypertensives, diazoxide, oestrogens.
Advice to Patient
Take with meals. Contact prescriber if there is fever, chest pain, rapid heartbeat, palpitations, flu-like symptoms, respiratory difficulty, skin rash, sore throat, numbness, tingling of extremities, muscle cramps, weakness, tremors or unresolved GI disturbance. Avoid alcohol. Follow diet and lifestyle changes as prescribed. Do not stop taking medication abruptly, decrease dosage gradually. Weigh daily at the same time, in the same clothes for the first 2 weeks and then weekly. Report prescriber if weight gain per week is greater than 5 lb. Change position slowly especially in the morning.
Pharmacokinetics
Onset of action: IV: 10-80 min. Duration: IM, IV: Up to 12 hrs. Absorption: Oral: Rapidly absorbed. Metabolism: Hepatic; extensive first-pass effect (oral). Bioavailability: Increased with food. Half-life elimination: 3-7 hrs. Time to peak, plasma: Oral: 1-2 hrs. Excretion: Urine.
Brands with this active ingredient
Compiled by Healify Pharmacy from published drug references. How we compile it →
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