Patient Medication Information: uses, side effects, how to take - Hydralazine
What HYDRALAZINE is used for:
- The treatment of high blood pressure in adults (hypertension). It is used together with other medicines for high blood pressure known as antihypertensives (e.g., beta-blockers and diuretics).
How HYDRALAZINE works:
HYDRALAZINE belongs to a group of medicines known as antihypertensives. The exact way it works is not known. However, it helps relax and widen blood vessels in the body so that blood can flow through the body more easily. This helps to lower blood pressure.
The ingredients in HYDRALAZINE are:
Medicinal ingredient: Hydralazine hydrochloride
Non-medicinal ingredients: Anhydrous lactose, microcrystalline cellulose, sodium starch glycolate, stearic acid, and FD&C Yellow #6
HYDRALAZINE comes in the following dosage form:
Tablets: 10 mg, 25 mg, and 50 mg of hydralazine hydrochloride
Do not use HYDRALAZINE if:
- You are allergic to hydralazine hydrochloride or any of the other ingredients in HYDRALAZINE • You are allergic to a class of antihypertensives known as hydrazinophthalazines • You have an autoimmune disease called systemic lupus erythematosus (SLE) • You have very fast, irregular, or pounding heartbeat (severe tachycardia) • You have heart failure with a high cardiac output (the heart pumps an unusually large amount of blood)
- You have heart failure due to high blood pressure in the vessels leading from the heart to the lungs (pulmonary hypertension)
- You have an overactive thyroid gland (thyrotoxicosis)
- You have any condition that causes narrowing of the valves in the heart or swelling around the heart (e.g., aortic stenosis, mitral stenosis, or constrictive pericarditis) • You have a serious tear in the body’s main artery, aorta (acute dissecting aneurysm) • You have a condition that causes narrowing or the blockage of the blood vessels that supply blood to the heart (coronary artery disease)
- You have a rare blood disorder affecting red blood cells called as porphyria Ask your healthcare professional if you are unsure.
To help avoid side effects and ensure proper use, talk to your healthcare professional before you take HYDRALAZINE. Talk about any health conditions or problems you may have, including if you:
- Have or had any heart problems including a previous heart attack
- Have problems with the blood flow to your brain
- Have kidney problems
- Have liver problems
- Are planning to undergo any surgery
Are pregnant or plan to be pregnant
- Are breast-feeding or plan to breast-feed. HYDRALAZINE can pass into breast milk • Are elderly
Other warnings you should know about:
Driving and operating machinery: HYDRALAZINE may lower your blood pressure. Do not drive or use machines until you know how HYDRALAZINE affects you
Testing and check-ups: Your healthcare professional will monitor and assess your health before and during your treatment with HYDRALAZINE. This includes monitoring the following: ▪ The profile of your blood; and
- The profile of your urine
Tell your healthcare professional about all the medicines you take, including any drugs, vitamins, minerals, natural supplements or alternative medicines.
The following may interact with HYDRALAZINE:
- Alcohol. You should not drink alcohol during your treatment with HYDRALAZINE • Corticosteroids, medicines used to suppress your immune system (e.g., hydrocortisone and prednisolone)
- Medines used to treat high blood pressure (e.g., diazoxide, calcium antagonists, vasodilators, angiotensin-converting enzyme (ACE) inhibitors, and beta blockers such as propranolol) • Epinephrine (adrenaline), a medicine used to raise blood pressure and treat allergic reactions • Glucose infusion solutions, used to treat low blood sugar or water loss • Monoamine oxidase (MAO) inhibitors, medicines used to treat depression • Medicines used to treat depression (e.g., monoamine oxidase inhibitors and tricyclic antidepressants)
- Non-steroidal anti-inflammatory drugs (NSAIDS), medicines used to reduce pain, inflammation, and fever (e.g., ibuprofen, indomethacin, and diclofenac)
- Estrogens, medicines used in birth control pills and in hormone replacement therapy (HRT) • Tranquilizers, medicines used to reduce anxiety or help with sleep
- Diuretics (also called fluid or water tablets), medicines used to increase the amount of water released in the urine
How to take HYDRALAZINE:
Take HYDRALAZINE exactly as directed by your healthcare professional • You can take HYDRALAZINE with or without food. Just make sure to take HYDRALAZINE in the same manner each time (e.g., always before, always during, or always after your meals) • Do NOT drink alcohol while you are taking this HYDRALAZINE
Usual dose:
Your healthcare professional will decide the right dose for you. This will depend on your health condition and how you respond to HYDRALAZINE.
The usual starting dose is 10 mg taken four times a day for the first 2 to 4 days. The dose may then be increased by your healthcare professional to the usual maintenance dose of 50 mg to 200 mg per day.
Overdose:
If you think you, or a person you are caring for, have taken too much HYDRALAZINE contact a healthcare professional, hospital emergency department, regional poison control centre or Health Canada’s toll-free number, 1-844 POISON-X (1-844-764-7669) immediately, even if there are no signs or symptoms.
Missed dose:
If you miss a dose of HYDRALAZINE, you do not need to make up the missed dose. Skip the missed dose and continue with your next scheduled dose. Do NOT take two doses to make up for the missed dose.
Possible side effects from using HYDRALAZINE:
These are not all the possible side effects you may have when taking HYDRALAZINE. If you experience any side effects not listed here, tell your healthcare professional.
The side effects of HYDRALAZINE may include:
- Chills,
- Fever,
- Blocked (congested) nose
Serious side effects and what to do about them
| Frequency/Side Effect/Symptom | Talk to your healthcare professional | Stop taking this drug | |||||||
| Only if severe | In all cases | and get immediate | |||||||
| medical help | |||||||||
| Very common | |||||||||
| Acute rheumatoid state (flare-up of existing rheumatoid arthritis): joint pain, swelling, stiffness, fatigue, fever, loss of appetite, or decreased range of motion | X | ||||||||
Gastrointestinal (GI) problems: diarrhea, constipation, nausea, vomiting, abdominal bloating, difficulty passing gas or stool, upper abdominal pain, fever, rapid heart beat, or tenderness when touching the abdomen | X | ||||||||
Heart problems: abnormally or irregular fast heartbeat, palpitations, chest pain, chest pressure, discomfort, shortness of breath, fatigue, weakness, nausea, cough, lack of appetite, or swelling in ankles, legs and feet | X | ||||||||
Nervous system problems: numbness, tingling, pins and needles, burning pain, muscle weakness, loss of coordination, increased sensitivity to touch, reduced reflexes, or muscle cramps | X | ||||||||
Systemic lupus erythematosus (autoimmune disease that occurs when the body’s immune system attacks its own tissues and organs): fatigue, fever, joint pain, stiffness | X | ||||||||
| Frequency/Side Effect/Symptom | Talk to your healthcare professional | Stop taking this drug | |||||||
| Only if severe | In all cases | and get immediate | |||||||
| medical help | |||||||||
| and swelling, rash, skin lesions, shortness of breath, chest pain, dry eyes, headaches, confusion, or memory loss | |||||||||
| Vasculitis (inflammation of the blood vessels): fever, fatigue, weight loss, muscle and joint aches and pain, rash, trouble breathing, coughing, numbness, weakness, or flushing | X | ||||||||
| Unknown | |||||||||
| Allergic reactions: hives, rash, itchiness, difficulty swallowing, difficulty breathing, wheezing, drop in blood pressure, nausea, vomiting, or swelling of the face, lips, tongue or throat | X | ||||||||
Blood disorders (including abnormal blood cell counts): fatigue, weakness, pale skin, shortness of breath, dizziness, lightheadedness, cold hands and feet, headache, fever, sore throat, frequent infections, frequent nosebleeds, easy bruising, bleeding more than normal from cuts or injuries, red or purple dots on the skin, heavy menstrual bleeding (in women), dark urine, rapid heart rate, mouth ulcers, wheezing, or diarrhea | X | ||||||||
| Eye problems: increased tear production, itchy eyes, red eyes with discharge, pink eye, swelling, blurred vision, or protruding eyeballs | X | ||||||||
| Frequency/Side Effect/Symptom | Talk to your healthcare professional | Stop taking this drug | |||||||
| Only if severe | In all cases | and get immediate | |||||||
| medical help | |||||||||
Hypotension (low blood pressure): dizziness, fainting, light- headedness, blurred vision, nausea, vomiting, or fatigue (may occur when going from lying or sitting to standing up) | X | ||||||||
| Kidney problems: blood in the urine, less urine, unable to urinate, fatigue, weakness, nausea, vomiting, shortness of breath, painful or uncomfortable feeling when urinating, high blood pressure, abdominal pain, back pain, weight loss, or swelling in the legs, ankles, or feet | X | ||||||||
| Liver problems: yellowing of the skin or eyes, urine turns dark, nausea, vomiting, lower stomach pain, abdominal pain, fever, itchiness, light colored stool, trouble thinking clearly, yellowing of the skin, fullness, or weight loss fatigue, | X | ||||||||
Mood or behavioral changes: agitation, anxiety, depression, hallucinations, feeling disorienting, sleeping problems, or low sex drive | X | ||||||||
Paradoxical pressor responses (unexpected high blood pressure): shortness of breath, fatigue, dizziness, fainting, chest pain, chest pressure, swelling in the ankles and legs, bluish lips and skin, racing pulse, or palpitations | X | ||||||||
| Pleural pain (pain of the lining of the lungs): sharp pain or stabbing | X | ||||||||
| Frequency/Side Effect/Symptom | Talk to your healthcare professional | Stop taking this drug | |||||||
| Only if severe | In all cases | and get immediate | |||||||
| medical help | |||||||||
| pain in chest that worses with breathing or coughing | |||||||||
If you have a troublesome symptom or side effect that is not listed here or becomes bad enough to interfere with your daily activities, tell your healthcare professional.
Reporting side effects
You can report any suspected side effects associated with the use of health products to Health Canada by:
- Visiting the Web page on Adverse Reaction Reporting (canada.ca/drug-device-reporting) for information on how to report online, by mail or by fax; or
- Calling toll-free at 1-866-234-2345.
NOTE: Contact your healthcare professional if you need information about how to manage your side effects. The Canada Vigilance Program does not provide medical advice.
Storage:
Store HYDRALAZINE at room temperature (15 - 30°C). Preserve in tight containers. and protect from light.
Keep out of reach and sight of children.
If you want more information about HYDRALAZINE:
- Talk to your healthcare professional
Find the full product monograph that is prepared for healthcare professionals and includes the
Patient Medication Information by visiting the Health Canada Drug Product Database website (Drug Product Database: Access the database); the manufacturer’s website (www.sanis.com), by calling 1-866-236-4076 or by emailing quality@sanis.com.
Sanis Health Inc.
1 President's Choice Circle
Brampton, Ontario L6Y 5S5
Date of Authorization: 2026-05-29