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Hydralazine Side Effects

Medically reviewed by Last updated on Dec 22, 2022.

Applies to hydralazine: oral tablet. Other dosage forms:

Serious side effects of Hydralazine

Along with its needed effects, hydralazine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking hydralazine:

More common

  • Arm, back, or jaw pain
  • chest pain or discomfort
  • chest tightness or heaviness
  • fast, pounding, or irregular heartbeat or pulse
  • nausea
  • shortness of breath
  • sweating

Less common

  • Black, tarry stools
  • blindness or vision changes
  • blisters on the skin
  • blurred vision
  • burning of the face or mouth
  • burning, crawling, itching, numbness, painful, prickling, "pins and needles", or tingling feelings
  • chills
  • clumsiness or unsteadiness
  • confusion
  • cough
  • difficult or labored breathing
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • fever and sore throat
  • general feeling of discomfort or illness or weakness
  • joint pain
  • lower back or side pain
  • muscle pain
  • numbness, tingling, pain, or weakness in the hands or feet
  • painful or difficult urination
  • pale skin
  • shakiness in the legs, arms, hands, or feet
  • skin rash or itching
  • swelling of the feet or lower legs
  • swollen, painful, or tender lymph glands in the neck, armpit, or groin
  • tightness in the chest
  • trembling or shaking of the hands or feet
  • ulcers, sores, or white spots in the mouth
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • weakness in hands or feet


  • Dark urine
  • light-colored stools
  • upper right abdominal or stomach pain
  • yellow eyes and skin

Get emergency help immediately if any of the following symptoms of overdose occur while taking hydralazine:

Symptoms of overdose

  • Feeling of warmth
  • headache
  • redness of the face, neck, arms, and occasionally, upper chest

Other side effects of Hydralazine

Some side effects of hydralazine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

  • Constipation
  • difficulty with moving
  • dizziness
  • feeling anxious or depressed
  • muscle cramps, pain, or stiffness
  • pain in the joints
  • rash, hives, welts, or itching
  • stuffy nose
  • watery eyes

For Healthcare Professionals

Applies to hydralazine: compounding powder, injectable solution, oral tablet.


The most frequently reported side effects were palpitations and tachycardia.[Ref]


Very common (10% or more): Palpitations, tachycardia

Common (1% to 10%): Angina pectoris, flushing, hypotension

Uncommon (0.1% to 1%): Heart failure, vasculitis

Very rare (less than 0.01%): Paradoxical pressor response[Ref]


Common (1% to 10%): Nausea, vomiting, diarrhea, gastrointestinal disturbances

Very rare (less than 0.01%): Paralytic ileus

Frequency not reported: Constipation[Ref]

Nervous system

Common (1% to 10%): Headache

Uncommon (0.1% to 1%): Dizziness

Very rare (less than 0.01%): Peripheral neuritis, paresthesia, tremor, polyneuritis

Frequency not reported: Tingling, numbness[Ref]


Common (1% to 10%): Arthralgia, joint swelling, myalgia

Uncommon (0.1% to 1%): Systemic lupus erythematosus-like syndrome

Frequency not reported: Muscle cramp[Ref]


Common (1% to 10%): Anorexia[Ref]


Common (1% to 10%): Positive antinuclear factor[Ref]


Uncommon (0.1% to 1%): Nasal congestion, dyspnea, pleural pain[Ref]


Uncommon (0.1% to 1%): Anemia, leukopenia, neutropenia, thrombocytopenia

Very rare (less than 0.01%): Hemolytic anemia, leukocytosis, lymphadenopathy, pancytopenia, splenomegaly, agranulocytosis, eosinophilia

Frequency not reported: Blood dyscrasias, hemoglobin decreased, red cell count decreased[Ref]


Uncommon (0.1% to 1%): Serum creatinine increased, glomerulonephritis

Very rare (less than 0.01%): Acute renal failure[Ref]


Uncommon (0.1% to 1%): Rash, purpura, urticaria, pruritus[Ref]


Uncommon (0.1% to 1%): Jaundice, liver enlarged, abnormal liver function, hepatitis[Ref]


Uncommon (0.1% to 1%): Hypersensitivity reaction[Ref]


Uncommon (0.1% to 1%): Proteinuria, hematuria, urinary retention

Very rare (less than 0.01%): Retroperitoneal fibrosis

Frequency not reported: Urination difficult[Ref]


Uncommon (0.1% to 1%): Lacrimation increased, conjunctivitis

Very rare (less than 0.01%): Exophthalmos[Ref]


Uncommon (0.1% to 1%): Edema, fever, weight decreased, malaise

Frequency not reported: Chills[Ref]


Uncommon (0.1% to 1%): Agitation, anxiety

Very rare (less than 0.01%): Depression, hallucinations

Frequency not reported: Psychotic reactions, disorientation, anxiety[Ref]


1. "Product Information. Apresoline (hydralazine)." Ciba-Geigy Pharmaceuticals (2001):

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

3. Cerner Multum, Inc. "Australian Product Information." O 0

4. "Product Information. HydrALAZINE Hydrochloride (hydralazine)." Akorn Inc (2016):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.