Hydrochlorothiazide is used on its own or together with other antihypertensive medicines to keep your blood pressure under control.
This medicine is also used to treat water retention caused by heart failure, kidney, or liver disease. Water retention may be noticed as swelling of the feet, ankles, lower leg and hands, or shortness of breath. For this reason, it is commonly known as a "water pill."
Take Hydrochlorothiazide exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.
You may need to pass urine more often while being treated with Hydrochlorothiazide. Take this medicine early in the day, preferably in the morning, to prevent you from frequently waking up at night to go to the toilet.
If taken in multiple daily dosing, the last dose should not be taken later than 6 in the evening unless instructed otherwise. Try to take it at the same time each day.
Hydrochlorothiazide must be taken regularly for it to be effective. Continue taking this medicine even when you feel better. Do not stop taking it unless instructed by the doctor.
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal schedule.
DO NOT double a dose under any circumstances.
If you often forget to take your medicine, let your doctor and pharmacist know.
Do not take Hydrochlorothiazide if you ever had an allergic reaction (e.g. rashes, breathlessness, swollen eyes) to this medicine or similar medicines such as sulfonamide-containing medicines.
Alert your doctor if you have anuria (a condition wherein you are unable to pass urine) as Hydrochlorothiazide may not be suitable for you.
Inform your doctor if you have the following conditions:
- fluid or electrolyte imbalance
- Addison's disease (a rare disorder where the adrenal glands produce insufficient amounts of certain hormones)
- diabetes
- high cholesterol
- asthma
- systemic lupus erythematosus (autoimmune disease that causes inflammation of certain organs in the body)
- gout (high uric acid level in the blood)
- liver disease
- severe kidney disease
Let your doctor know if you are pregnant or breastfeeding.
If you are going to have an operation, including minor surgery and dental work, inform your doctor or dentist that you are taking Hydrochlorothiazide.
What lifestyle changes can I make to improve my blood pressure?
Regular exercise and eating a healthy diet will help control your blood pressure and improve your overall health. Engage in physical activity like walking for at least 30 to 60 minutes on most days of the week. If you have not exercised for a long time, start with light exercises such as slow walks. Speak to your doctor about what type of exercise would be suitable for you. Follow a healthy diet plan by eating more fruits, vegetables, whole grains and low-fat dairy products and reduce your intake of foods high in saturated fat, cholesterol and sodium. Cutting down on deep-fried foods and using less salt when cooking can kick-start your healthy diet.
If you smoke, you should try to quit. Smoking is harmful to your blood pressure, heart and overall health. Speak to your doctor or pharmacist about ways to stop your smoking habit.
Why is it important to keep my appointments with the doctor?
Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.
- Your blood pressure may fall to unsafe levels without you noticing it. Monitor your blood pressure during treatment.
- Routine tests (e.g. liver and kidney function, electrolyte levels, eye and ear examinations) may be done while you are being treated with this medicine. Your doctor will advise you about how often you need to have these tests.
- Regular monitoring of skin reactions (e.g. new skin lesions) may also be needed.
Hydrochlorothiazide may cause any of the following side effects: headache, dizziness, nausea, vomiting, stomach irritation or cramping, diarrhoea, constipation, loss of appetite, weakness, muscle spasm, numbness or tingling sensation in the hands and feet, hair loss, and skin rash.
This medicine may also make your skin more sensitive to sunlight. Apply sunscreen when going outdoors and avoid prolonged exposure to sunlight and UV lamps.
It may also cause your blood pressure to fall suddenly when you get up from a sitting or lying down position and you may feel giddy. To minimise this problem, stand up slowly.
Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
- rashes, breathlessness, swelling of the face, eyes or mouth
- changes in colour or size of a mole, suspicious skin changes, skin lump or growth
- blurred or yellow vision, decrease in vision or pain in your eyes due to high pressure
This medicine may cause the level of your red blood cells, white blood cells and platelets to drop.
Red blood cells carry oxygen around your body. A fall in the level of red blood cells may make you feel tired and worn out.
White blood cells help your body to fight infections. A fall in the level of your white blood cells may put you at higher risk for infections, such as coughs, colds and flu, which may lead to more serious infections. Avoid crowded places and people who are sick. Inform your doctor if you have a fever, cough, or flu that does not go away.
Platelets help your blood to clot when there is a cut in the skin. A fall in the level of your platelets may put you at risk of bleeding more than usual. Do not take part in activities where you may fall or get injured, such as contact sports. Inform your doctor if you get any unusual bruising (large bruises or several bruises, especially if the bruises appeared on their own) or bleeding that takes a long time to stop (for example, too much bleeding when you floss or brush your teeth).
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Inform your doctor and pharmacist if you are taking any of these medicines:
- lithium (medicine for mood disorders)
- medicines for diabetes
- other medicines for high blood pressure
- cholesterol-lowering medicines e.g. cholestyramine, colestipol
- corticosteroids (anti-inflammatory medicine)
- medicines used for blocking pain and sensation, and relaxing the muscles during procedures
This list does not include all medicines that may interact with Hydrochlorothiazide.
Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicine, supplements, and medicines that you buy without a prescription.
Avoid alcohol.
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.
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