Hydralazine is a medication used to treat hypertension, and it is available both orally and intravenously. Its method of action is relaxation and dilation of peripheral arteries, resulting in decreased blood pressure. However like all medical interventions, hydralazine has its own side effect profile which must be weighed before beginning therapy.
Low Blood Pressure
Hydralazine is a potent dilator of the arterial system which results in decreased blood pressure. When the drop in blood pressure is excessive, it is known as hypotension. The decreased blood pressure results in increased heart rate (tachycardia), dizziness and possible loss of consciousness. Damage to internal organs such as the heart or kidneys is also possible due to the decreased blood flow that results when blood pressure drops.
Lupus-like Syndrome
Hydralazine can also cause lupus-like symptoms in some patients. These include chills, muscle aches, joint pains, skin blisters, rash, itchiness, hives (urticaria) and a sore throat. Often patients have a hereditary history of such a reaction and it can also occur in patients with diminished kidney function. If these symptoms occur, drug cessation is advised.
Nerve Damage
Neuropathy, or nerve damage, can also result from hydralazine usage. Symptoms include numbness, tingling and pain in the hands or feet. The addition of pyridoxine, or Vitamin B6, is advised if these symptoms develop.
Blood Side Effects
The cells that compose blood can also be affected by hydralazine therapy, including decreased counts of white blood cells (known as leucopenia) or failure of the bone marrow to make enough white blood cells (agranulocytosis). This is why blood cell counts are done periodically during hydralazine therapy; if any evidence of blood toxicity is evident, treatment should be stopped.
Gastrointestinal Effects
Gastrointestinal effects are less common but include constipation, diarrhea, decreased appetite and nausea. Low dose therapy with gradually increasing doses often helps alleviate gastrointestinal complaints.
Cardiac Effects
Due to the effects on the cardiovascular system, patients commonly complain of cardiac symptoms such as chest pain, palpitations and increased heart rate. Low dose therapy is recommended for these symptoms with gradual increase of dosing as tolerated by the patient.
Anaphylaxis
Hydralazine can cause an anaphylactic reaction. Patients will commonly complain of itching, swelling, hives, trouble breathing and watery eyes. If these symptoms develop, immediately stop treatment and consult a physician.
References
- Medline Plus: Hydralazine
- "Journal of Emergency Medicine;" Parenteral hydralazine revisited; Adelman, RD et al. Volume 16, 1998
Member Comments