Hydroxyzine vs. hydralazine: What’s the difference?
- Hydroxyzine is an antihistamine with anticholinergic (drying) and sedative properties that is used to treat itching caused by various allergic reactions. Hydroxyzine is also used to treat anxiety and tension, to induce sedation prior to or after anesthesia, and to treat nausea, vomiting, and alcohol withdrawal.
- Hydralazine is used to treat hypertension (high blood pressure), alone or in combination with other blood pressure medications. It is also used to treat hypertensive crisis and congestive heart failure.
- A brand name for hydroxyzine is Vistaril.
- A brand name for hydralazine is Apresoline.
- Side effects of hydroxyzine and hydralazine that are similar include loss of appetite and nausea.
- Side effects of hydroxyzine that are different from hydralazine include drowsiness, tiredness, sleepiness, dizziness, problems with coordination, drying and thickening of oral and other respiratory secretions, upset stomach, confusion, dry mouth, nervousness, irritability, blurred or double vision, tremors, and seizures.
- Side effects of hydralazine that are different from hydroxyzine include headache, vomiting, diarrhea, palpitations, rapid heartbeat, and chest pain (angina).
What are hydroxyzine and hydralazine?
Hydroxyzine is an antihistamine with anticholinergic (drying) and sedative properties used to treat itching caused by allergic reactions. It is also used to treat anxiety and tension, and for inducing sedation prior to or after anesthesia. Hydroxyzine also is used to treat nausea, vomiting, and alcohol withdrawal.
Hydralazine is an antihypertensive medication used to treat high blood pressure. It is a peripheral arterial vasodilator that causes relaxation of blood vessels, which carry blood away from the heart and toward the organs and tissues. Hydralazine has shown to be beneficial for the treatment of congestive heart failure (CHF) when used in combination with isosorbide dinitrate (Isordil, Isordil Titradose, Dilatrate-SR) as an alternative for patients who cannot tolerate ACE inhibitors.
What are the side effects of hydroxyzine and hydralazine?
Common side effects of hydroxyzine are:
- Disturbed coordination
- Drying and thickening of oral and other respiratory secretions
- Stomach distress
Other important side effects include:
Hydroxyzine should be used with caution (if at all) in persons with narrow-angle glaucoma, prostatic hypertrophy (enlarged prostate gland), hyperthyroidism, cardiovascular disease, hypertension, and asthma.
Common side effects of hydralazine are:
Other less commonly reported side effects include:
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What is the dosage of hydroxyzine vs. hydralazine?
- Hydroxyzine has its maximal effect about 30 to 60 minutes after it is taken. Its effects last for 4 to 6 hours.
- The recommended dose for treating itching (pruritus) is 25 mg given 3 or 4 times daily by mouth or by intramuscular injection.
- When used for sedation, the recommended dose is 50 to 100 mg orally or 25 to 100 mg by intramuscular injection.
- Anxiety and tension are managed with 50 to 100 mg in 4 divided doses or 50 to 100 mg intramuscular injection in 4 or 6 divided doses.
- Alcohol withdrawal is treated with a 50 to 100 mg injection and may be repeated every 4 to 6 hours as needed.
- The dose for nausea and vomiting is 25 to 100 mg by injection.
- Hydroxyzine can be taken with or without food.
Hypertension in adult patients:
- Start treatment at a low dose and increase gradually based on individual patient response. The usual recommended starting regimen is 10 mg orally four times daily for the first 2 to 4 days, increase to 25 mg four times daily for the remainder of the first week.
- For the second and subsequent weeks, increase dosage to 50 mg four times daily (increase dose by 10 to 25 mg/dose gradually every 2 to 5 days).
- The maximum daily dose used in clinical studies is 300 mg.
Congestive heart failure:
- The initial dose for treating heart failure is 10 to 25 mg orally 3 to 4 times daily.
- The usual dose is 225 to 300 mg daily in 3 to 4 divided doses.
For pediatric hypertensive emergencies, the dose is 0.5 mg/Kg IV every 4 hours.
What drugs interact with hydroxyzine and hydralazine?
Hydroxyzine also adds to the sedating effects of the narcotic class of pain medications and its derivatives, for example:
Hydroxyzine also adds to the effects of the tricyclic class of antidepressants, for example:
Hydroxyzine also adds to the effects of certain antihypertensive medications, for example:
Hydroxyzine can also intensify the drying effects of other medications with anticholinergic properties, for example:
When using these drugs, the dose of hydroxyzine may require reduction.
Sympathomimetics may decrease the effectiveness of hydralazine, for example:
Co-administration of these agents may block the antihypertensive benefits of hydralazine treatment.
Are hydroxyzine and hydralazine safe to use while pregnant or breastfeeding?
- A limited number of studies of hydroxyzine in pregnant women suggests that there may be a relationship between its use in the first trimester of pregnancy and congenital abnormalities in the fetus. Therefore, hydroxyzine should be avoided during the first trimester of pregnancy.
- It is not known whether hydroxyzine is excreted into breast milk. In general, antihistamines are not recommended for use during breastfeeding because they can cause stimulation or seizures in newborns.
Hydralazine should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus. Hydralazine is classified as FDA pregnancy risk category C (Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks). It is used for treating high blood pressure during pregnancy.
Hydralazine is excreted in breast milk. Hydralazine should be used cautiously in females who are breastfeeding if treatment is necessary.
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Medically Reviewed on 5/6/2019
FDA Prescribing Information