Diuretics

by Food and Drug Administration (FDA)

How you take a drug affects how well it works and how safe it will be for you. Sometimes it can be as important as what you take. Timing, what you eat and when you eat, proper dose, and many other factors can mean the difference between getting better, staying the same, or even getting worse. This drug information page is intended to help you make your treatment work as well as possible. It is important to note, however, that this is only a guideline. You should talk to your doctor or pharmacist about how and when to take any prescribed drug.

This installment in a series of articles on commonly prescribed drugs is about a particular group of diuretics called potassium-sparing diuretics-hydrochlorothiazide combinations. They are used primarily for treating high blood pressure.

This medicine is a combination of two types of diuretics — potassium-sparing and hydrochlorothiazides — that help decrease the amount of water and sodium in the body by acting on the kidneys to increase the flow of urine. Other diuretics tend to reduce the amount of potassium in the body. But potassium sparing diuretics help retain or spare this electrolyte. Potassium is vital to body functions, including muscle contraction.

These drugs come in pill form in three formulations: amiloride and hydrochlorothiazide; spironolactone and hydrochlorothiazide; and triamterene and hydrochlorothiazide, the most frequently prescribed.

Conditions These Drugs Treat

Potassium-sparing diuretics-hydrochlorothiazide combinations are most commonly used to control high blood pressure (hypertension). Untreated, high blood pressure can cause serious problems such as heart failure, blood vessel disease, stroke, or kidney failure.

People taking this medicine for high blood pressure may have to take it the rest of their lives, even though they may not feel sick.

In addition to the drug, doctors may also prescribe a low-salt diet to help reduce hypertension. The medicine is usually more effective when the diet is followed properly.

This medicine is also used to reduce swelling, such as in the ankles or lungs, caused by an excessive amount of water in the body. However it is usually not used for treating the normal swelling of feet and hands that occurs during pregnancy.

How to Take

Because this medicine may increase the frequency of urination, it is best to plan your dose or doses so they least affect your daily schedule or sleep. If you are taking only one dose a day, take it in the morning after breakfast. If you are taking more than one dose, take the last dose no later than 6 p.m., unless directed otherwise by your doctor. To make it easier to remember to take your medicine, take it at the same time each day.

If the medicine upsets your stomach, it may be taken with meals or a glass of milk. This will help prevent stomach upset.

Missed Doses

A missed dose should be taken as soon as possible. However, if it's almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take double doses.

Relief of Symptoms

If this medicine is being used to control hypertension, there may be no noticeable effects. High blood pressure may not have any outward signs. In fact, most people with high blood pressure feel normal.

It is important to continue to take the medicine exactly as directed and to keep appointments with your doctor even if you feel well.

If this medicine is being used to reduce swelling, its effects should be noticeable in anywhere from a few days to a few weeks, depending on the condition it is being used to treat.

Side Effects and Risks

Initially, this medicine may cause unusual tiredness and an increase in the amount of urine and frequency of urination. These effects should lessen after you have taken the medicine for a few weeks.

This medicine also may increase or decrease the amount of potassium in your body, depending on which of the two components of the drug have the predominant effect. For this reason, doctors ordinarily do blood tests the first few months you're on the drug and periodically thereafter to monitor the amount of potassium in your body. To offset any decrease or increase, your doctor may instruct you to eat or avoid certain foods. For example, you may be advised to eat foods or drink beverages that have a high potassium content (e.g., citrus fruit juices and bananas), use salt substitutes, or take a potassium supplement. However, do not use salt substitutes or low-sodium milk unless your doctor tells you to because they may contain potassium. Too much or too little potassium can be harmful.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.