Hydralazine

You should not use this medication if you are allergic to hydralazine, or if you have coronary artery disease, or rheumatic heart disease affecting the mitral valve.

Before taking hydralazine, tell your doctor if you have kidney disease, lupus, angina pectoris (chest pain), or if you have ever had a stroke.

While taking hydralazine, avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Get up slowly and steady yourself to prevent a fall.

Call your doctor at once if you have a serious side effect such as fast or pounding heartbeats, swelling, numbness or tingling, dark-colored urine, joint pain or swelling with fever, chest pain, weakness or tired feeling, and urinating less than usual or not at all.

To be sure this medication is helping your condition and is not causing harmful effects, your blood pressure will need to be checked often. You may also need occasional blood tests. Do not miss any scheduled appointments.

Keep using hydralazine as directed, even if you feel well. High blood pressure often has no symptoms, so you may not know when your blood pressure is high. You may need to use blood pressure medication for the rest of your life.

Hydralazine is part of the drug class:

• Hydrazinophthalazine derivatives

Serious side effects have been reported with hydralazine. See the “Hydralazine Precautions” section.

Common side effects of hydralazine include the following:

• headache
• anorexia
• nausea/vomiting
• diarrhea
• palpitations
• tachycardia
• angina pectoris

This is not a complete list of hydralazine side effects. Ask your doctor or pharmacist for more information.

Tell your doctor if you have any side effect that bothers you or that does not go away.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Although the precise mechanism of action of Hydralazine is not fully understood, the major effects are on the cardiovascular system.  Hydralazine apparently lowers blood pressure by exerting a peripheral vasodilating effect through a direct relaxation of vascular smooth muscle.  Hydralazine, by altering cellular calcium metabolism, interferes with the calcium movements within the vascular smooth muscle that are responsible for initiating or maintaining the contractile state. 

The peripheral vasodilating effect of Hydralazine results in decreased arterial blood pressure (diastolic more than systolic); decreased peripheral vascular resistance; and an increased heart rate, stroke volume and cardiac output.  The preferential dilatation of arterioles, as compared to veins, minimizes postural hypotension and promotes the increase in cardiac output.  Hydralazine usually increases renin activity in plasma presumably as a result of increased secretion of renin by the renal juxtaglomerular cells in response to reflex sympathetic discharge.  This increase in renin activity leads to the production of angiotensin II, which then causes stimulation of aldosterone and consequent sodium reabsorption.  Hydralazine also maintains or increases renal and cerebral blood flow.

The average maximal decrease in blood pressure usually occurs 10 to 80 minutes after administration of Hydralazine hydrochloride injection.  No other pharmacokinetic data on Hydralazine hydrochloride injection are available.

Hypersensitivity to Hydralazine, coronary artery disease, mitral valvular rheumatic heart disease.

• Apresoline
• Hydralazine HCl
• Hydralazine Hydrochloride

Hypertension: Management of moderate to severe hypertension

Note: According to the Eighth Joint National Committee (JNC 8) guidelines, hydralazine is not recommended for the initial treatment of hypertension (James, 2013).

Tablets: Store at 15ºC to 30ºC (59ºF to 86ºF).

Injection: Store at 20ºC to 25ºC (68ºF to 77ºF); use immediately after vial is opened. Solution may discolor upon contact with metal; discard discolored solutions.

Frequency not defined.

Cardiovascular: Angina pectoris, circulatory shock, flushing, orthostatic hypotension, palpitations, paradoxical pressor response, peripheral edema, tachycardia

Central nervous system: Anxiety, chills, depression, disorientation, dizziness, headache, increased intracranial pressure (IV; in patient with pre-existing increased intracranial pressure), peripheral neuritis, psychotic reaction

Dermatologic: Diaphoresis, pruritus, skin rash, urticaria

Gastrointestinal: Anorexia, constipation, diarrhea, nausea, paralytic ileus, vomiting

Genitourinary: Dysuria, impotence

Hematologic & oncologic: Agranulocytosis, decreased hemoglobin, decreased red blood cells, eosinophilia, hemolytic anemia, leukopenia

Neuromuscular & skeletal: Lupus-like syndrome (dose related; fever, arthralgia, splenomegaly, lymphadenopathy, asthenia, myalgia, malaise, pleuritic chest pain, edema, positive ANA, positive LE cells, maculopapular facial rash, positive direct Coombs' test, pericarditis, pericardial tamponade), muscle cramps, rheumatoid arthritis, tremor, weakness

Ophthalmic: Conjunctivitis, lacrimation

Respiratory: Dyspnea, nasal congestion

Miscellaneous: Fever

<1% (Limited to important or life-threatening): Thrombocytopenia (IV)

Blood pressure (monitor closely with IV use), standing and sitting/supine, heart rate, complete blood cell count (CBC), antinuclear antibody (ANA) titer

Oral:
-Initial dose: 0.75 mg/kg/day in 4 divided doses
-May increase gradually over 3 to 4 weeks to a maximum of 7.5 mg/kg/day or 200 mg/day

Comments:
-Safety and effectiveness have not been established in pediatric patients in controlled clinical trials, however, there is experience with use of this drug in children at the provided doses.

Use. For the treatment of essential hypertension, alone or as an adjunct

Parenteral: 1.7 to 3.5 mg/kg/day IM or IV in 4 to 6 divided doses

Comments:
-Safety and effectiveness have not been established in pediatric patients in controlled clinical trials, however, there is experience with use of this drug in children at the provided doses.

Use: For the treatment of severe essential hypertension when this drug cannot be given orally or when there is an urgent need to lower blood pressure

Safety and effectiveness have not been established in pediatric patients in controlled clinical trials, however, there is experience with use of this drug in children at the provided doses.

Consult WARNINGS section for additional precautions.

• Used for the treatment of high blood pressure (BP), either alone or in combination with other agents.
• Available as oral tablets or in an injectable form. The injectable form of hydralazine may be used by healthcare providers when there is an urgent need to lower blood pressure or if the oral tablets cannot be given.
• Hydralazine also improves blood flow to the outer extremities (such as the fingers and toes), increases heart rate and the volume of blood pumped with each heartbeat, and overall heart performance.
• More effective at reducing diastolic (the bottom number of a BP reading) rather than systolic (the top number of a BP reading) blood pressure.
• Less likely to cause a drop in blood pressure on standing (postural hypotension) as it preferentially targets arteries rather than veins.
• In people with high blood pressure and healthy kidneys, hydralazine tends to increase blood flow through the kidneys, improving kidney function. However, it should be used with caution in people with advanced kidney damage.
• Hydralazine oral tablets are only available as a generic.

• May be taken with or without food, but should be taken consistently either with or without food. Food may increase the blood levels of hydralazine, increasing the risk of side effects such as a blood pressure drop when standing.
• Be cautious driving or performing tasks that require concentration if hydralazine makes you dizzy. Also be careful when going from a sitting or lying down to a standing position. Alcohol, dehydration, exercise, or illness may exacerbate these effects.
• Tell your doctor if you experience any chest pain or heart palpitations while taking hydralazine.
• Seek urgent medical advice if you develop a rash, fever, joint or muscle pain, difficulty breathing, or numbness or nerve pain in your hands or feet.
• Talk to your doctor or pharmacist before buying other medications over the counter to check that they are compatible with hydralazine.