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- What is Hydralazine? What is Hydrochlorothiazide?
- What are the side effects of hydralazine and hydrochlorothiazide?
- What is the dosage for hydralazine and hydrochlorothiazide?
- What drugs interact with hydralazine and hydrochlorothiazide?
- Are hydralazine and hydrochlorothiazide safe to use when pregnant or breastfeeding?
Hydralazine vs. hydrochlorothiazide: What's the difference?
- Hydralazine and hydrochlorothiazide are used to treat high blood pressure and congestive heart failure (CHF).
- Hydralazine is also used to treat hypertensive crisis.
- Hydrochlorothiazide is also used to treat excessive fluid accumulation and swelling (edema) of the body caused by cirrhosis, chronic kidney failure, corticosteroid medications, and nephrotic syndrome.
- A brand name for hydrochlorothiazide is Microzide.
- Hydralazine and hydrochlorothiazide belong to different drug classes. Hydralazine is a peripheral arterial vasodilator and hydrochlorothiazide is a diuretic (water pill).
- A brand name for hydralazine is Apresoline.
- Side effects of hydralazine and hydrochlorothiazide that are similar include low blood pressure and nausea.
- Side effects of hydralazine that are different from hydrochlorothiazide include headache, weight loss, vomiting, diarrhea, palpitations, rapid heartbeat chest pain (angina), constipation, paralytic ileus, fluid retention (edema), shortness of breath, numbness and tingling of extremities, tremors, muscle cramps, psychotic reactions, difficulty urinating, blood disorders, hypersensitivity type reactions, nasal congestion, flushing, abnormal tear production, and conjunctivitis.
- Side effects of hydrochlorothiazide that are different from hydralazine include weakness, light sensitivity (rash caused by sunlight), impotence, and abdominal pain.
What is Hydralazine? What is Hydrochlorothiazide?
Hydralazine is a peripheral arterial vasodilator used as an antihypertensive medication to treat high blood pressure, hypertensive crisis, and congestive heart failure (CHF). Hydralazine causes relaxation of blood vessels which carry blood away from the heart and towards the organs and tissues. Hydrazine affects calcium movement within blood vessels. Calcium is required for muscle contraction and therefore disturbances in calcium movement may cause smooth muscle relaxation in the blood vessels. Hydralazine is selective for arterioles (small arteries), and the overall effects of treatment include a decrease in arterial blood pressure, and peripheral vascular resistance.
Hydrochlorothiazide is a diuretic (water pill) used to treat high blood pressure (hypertension). Hydrochlorothiazide is used to treat excessive fluid accumulation and swelling (edema) of the body caused by heart failure, cirrhosis, chronic kidney failure, corticosteroid medications, and nephrotic syndrome. It works by blocking salt and fluid reabsorption from the urine in the kidneys, causing increased urine output (diuresis). Hydrochlorothiazide can be used to treat calcium-containing kidney stones because it decreases the amount of calcium excreted by the kidneys in the urine and thus decreases the amount of calcium in urine to form stones.
What are the side effects of hydralazine and hydrochlorothiazide?
Common side effects of hydralazine are:
- tachycardia (rapid heartbeat), and
- angina pectoris (chest pain).
Other less commonly reported side effects include:
- paralytic ileus,
- low blood pressure,
- paradoxical pressor response,
- dyspnea (shortness of breath),
- peripheral neuritis,
- muscle cramps,
- psychotic reactions,
- difficulty urinating,
- blood disorders,
- hypersensitivity type reactions,
- nasal congestion,
- abnormal tear production (lacrimation) , and
Side effects of hydrochlorothiazide include
- low blood pressure,
- light sensitivity (rash caused by sunlight),
- nausea, and
- abdominal pain.
- More serious side effects include
- electrolyte disturbances,
- jaundice, and
- anaphylaxis (a life-threatening allergic reaction).
Patients allergic to sulfa may also be allergic to hydrochlorothiazide because of the similarity in the chemical structure of the medications.
Hydrochlorothiazide can aggravate kidney dysfunction and is used with caution in patients with kidney disease. Hydrochlorothiazide can lower blood potassium, sodium, and magnesium levels. Low potassium and magnesium levels can lead to abnormalities in heart rhythm, especially in patients already taking digoxin (Lanoxin). During hydrochlorothiazide treatment, supplementation with potassium is common to prevent low potassium levels.
Blood uric acid levels can increase during hydrochlorothiazide treatment, and this elevation may cause an episode of acute gout in some individuals. Thiazide diuretics may increase blood sugar (glucose) levels and precipitate diabetes.
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What is the dosage for hydralazine and hydrochlorothiazide?
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 10-25 mg/dose gradually every 2-5 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.
- Hydrochlorothiazide may be taken with or without food.
- The usual adult dose for hypertension is 12.5 to 50 mg once daily.
- The usual adult dose for treating edema is 25-100 mg once daily or in divided doses.
What drugs interact with hydralazine and hydrochlorothiazide?
The following sympathomimetics may decrease the effectiveness of hydralazine:
- dobutamine (Dobutrex),
- dopamine (Intropin),
- norepinephrine (Levophed),
- epinephrine (Adrenalin),
- metaraminol (Aramine),
- phenylephrine, (NeoSynephrine, Neofrin)
- ephedra (Ma Huang), and
Co-administration of these agents may block the anti-hypertensive benefits of hydralazine treatment.
Nonsteroidal anti-inflammatory drugs (NSAIDs), for example, ibuprofen (Motrin), may reduce the blood pressure lowering effects of hydrochlorothiazide. Blood sugar levels can be elevated by hydrochlorothiazide, necessitating adjustment in the doses of medications that are used for treating diabetes.
Combining hydrochlorothiazide with corticosteroids may increase the risk for low levels of blood potassium and other electrolytes. Low blood potassium (hypokalemia) can increase the toxicity of digoxin (Lanoxin).
Are hydralazine and hydrochlorothiazide safe to use when pregnant or breastfeeding?
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.
There are no adequate studies of hydrochlorothiazide in pregnant women. Thiazides may increase the risk of fetal or neonatal jaundice, low platelet levels, and possibly other adverse reactions that have occurred in adults.
Hydrochlorothiazide is excreted in breast milk. Intense diuresis using hydrochlorothiazide may reduce the production of breast milk. Otherwise hydrochlorothiazide is considered safe to use during nursing if required by the mother.
Hydralazine (Apresoline) and hydrochlorothiazide (Microzide) Hydralazine and hydrochlorothiazide are used to treat high blood pressure and congestive heart failure (CHF). Hydralazine is also used to treat hypertensive crisis. Hydrochlorothiazide is also used to treat excessive fluid accumulation and swelling (edema) of the body caused by cirrhosis, chronic kidney failure, corticosteroid medications, and nephrotic syndrome.
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Related Disease Conditions
High Blood Pressure (Hypertension)
High blood pressure (hypertension) is a disease in which pressure within the arteries of the body is elevated. About 75 million people in the US have hypertension (1 in 3 adults), and only half of them are able to manage it. Many people do not know that they have high blood pressure because it often has no has no warning signs or symptoms. Systolic and diastolic are the two readings in which blood pressure is measured. The American College of Cardiology released new guidelines for high blood pressure in 2017. The guidelines now state that blood normal blood pressure is 120/80 mmHg. If either one of those numbers is higher, you have high blood pressure. The American Academy of Cardiology defines high blood pressure slightly differently. The AAC considers 130/80 mm Hg. or greater (either number) stage 1 hypertension. Stage 2 hypertension is considered 140/90 mm Hg. or greater. If you have high blood pressure you are at risk of developing life threatening diseases like stroke and heart attack.REFERENCE: CDC. High Blood Pressure. Updated: Nov 13, 2017.
Portal hypertension is most commonly caused by cirrhosis, a disease that results from scarring of the liver. Other causes of portal hypertension include blood clots in the portal vein, blockages of the veins that carry the blood from the liver to the heart, and a parasitic infection called schistosomiasis. Symptoms of portal hypertension include varices (enlarged veins), vomiting blood, blood in the stool, black and tarry stool, ascites (abnormal fluid collection within the peritoneum, the sac that contains the intestines within the abdominal cavity), confusion and lethargy, splenomegaly or enlargement of the spleen, and decreased white blood cell counts.
Pulmonary hypertension is elevated pressure in the pulmonary arteries that carry blood from the lungs to the heart. The most common symptoms are fatigue and difficulty breathing. If the condition goes undiagnosed, more severe symptoms may occur. As pulmonary hypertension worsens, some people with the condition have difficulty performing any activities that require physical exertion. While there is no cure for pulmonary hypertension, it can be managed and treated with medications and supplemental oxygen to increase blood oxygen levels.
Hypertension-Related Kidney Disease
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Hypertensive Kidney Disease
High blood pressure can damage the kidneys and is one of the leading causes of kidney failure (end-stage renal kidney disease). Kidney damage, like hypertension, can be unnoticeable and detected only through medical tests. If you have kidney disease, you should control your blood pressure. Other treatment options include prescription medications.
Pseudotumor Cerebri (Idiopathic Intracranial Hypertension)
Pseudotumor Cerebri (intracranial hypertension) is a condition where there is an increase in pressure of fluid surrounding the brain and spinal cord (cerebrospinal fluid or CSF) mimicing a brain tumor. The cause is unknown. The most common symptom is headache but also include eye-pain, vision loss and double vision. Pseudotumor cerebri is diagnosed with MRI or CAT scans and treated by discontinuing offending medications (if applicable), weight loss and diuretic medications. The condition can also be helped by repeated drainage of spinal fluid using the lumbar puncture.
Preeclampsia (Pregnancy Induced Hypertension)
Preeclampsia is related to increased blood pressure and protein in the mother's urine. Preeclampsia typically begins after the 20th week of pregnancy. When preeclampsia causes seizures, it is termed "eclampsia" and is the second leading cause of maternal death of in the US. Preeclampsia is the leading cause of fetal complications. Risk factors for preeclampsia include high blood pressure, obesity, multiple births, and women with preexisting medical conditions such as diabetes, kidney disease, rheumatoid arthritis, lupus, or scleroderma. Pregnancy planning and lifestyle changes may reduce the risk of preeclampsia during pregnancy.
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