Hypezide

Indications

• High blood pressure (hypertension), alone or together with other blood pressure medicines.
• Fluid build-up and swelling (oedema) caused by heart failure, liver disease, kidney disease or some medicines.

How It Works

Hydrochlorothiazide is a diuretic, often called a "water tablet". It acts on the kidneys so that more salt and water leave the body in the urine. This lowers the amount of fluid in the blood vessels, reduces swelling and, over time, helps the blood vessels relax so blood pressure falls.

Dosage and Administration

• High blood pressure (adults): usually 12.5 to 25 mg once a day. Some people need up to 50 mg a day, as prescribed.
• Oedema (adults): usually 25 to 50 mg a day, sometimes more for a short time, as prescribed.
• Children: only as prescribed by the doctor according to body weight.

Take it in the morning so that extra urination does not disturb sleep. It can be taken with or without food. Keep taking it even when you feel well, unless the doctor tells you to stop.

Interactions

• Lithium: levels can rise to a harmful level.
• Digoxin and some heart rhythm medicines: low potassium caused by this medicine increases the risk of side effects.
• Painkillers such as Ibuprofen and Diclofenac can weaken its effect and strain the kidneys.
• Corticosteroids and high doses of Salbutamol can lower potassium further.
• Medicines for diabetes may need adjusting, because it can raise blood sugar.
• Other blood pressure medicines and alcohol can add to dizziness.
• Colestyramine reduces its absorption; take them at least 4 hours apart.

Contraindications

• Allergy to hydrochlorothiazide or to sulfonamide ("sulfa") medicines.
• Severe kidney failure with little or no urine.
• Severe liver failure.
• Low potassium or low sodium, or high calcium, that has not been corrected.
• Addison's disease.

Side Effects

Common: passing urine more often, dizziness when standing up, low potassium (weakness, muscle cramps), raised blood sugar and uric acid (which can trigger gout), raised cholesterol, upset stomach, skin that burns easily in the sun, and erection problems. Long-term use has been linked to a higher risk of some skin cancers, so protect your skin from the sun.

Get urgent medical help for sudden eye pain or blurred vision (usually within weeks of starting), fainting, a fast or irregular heartbeat, severe muscle weakness, confusion, sudden breathlessness, severe stomach pain, or a severe rash with blistering or swelling of the face.

Pregnancy and Lactation

It is usually not used in pregnancy, as it can reduce the blood supply to the baby and affect the newborn; the doctor will choose the safest option. Small amounts pass into breast milk, and higher doses may reduce milk supply. Ask your doctor before using it while breastfeeding.

Precautions and Warnings

• Regular blood tests for potassium, sodium, kidney function and blood sugar are advised.
• Use with care in diabetes, gout, lupus, and liver or kidney disease, and in older people.
• Stand up slowly to avoid dizziness.
• If you have severe vomiting, diarrhoea or heavy sweating, contact your doctor, as you may become dehydrated.
• Use sun protection and avoid strong sunlight.

Overdose

Too much can cause heavy urination, dehydration, dizziness, weakness, muscle cramps, confusion and an irregular heartbeat due to low potassium or sodium. Seek medical help straight away.

Therapeutic Class

Thiazide diuretic; antihypertensive.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.