What to Know About Indapamide

Indapamide is a medication for hypertension (high blood pressure) and fluid retention (edema) due to congestive heart failure. It is categorized in a class of drugs called thiazide diuretics. Diuretics are sometimes referred to as water pills because they act directly on the kidneys to promote diuresis (urine flow).

Indapamide is available as an oral (by mouth) tablet. The brand name for indapamide is Lozol, but Lozol has been discontinued, so only the generic version (indapamide) is available.

Uses

The Food and Drug Administration (FDA) has approved indapamide for the treatment of:

• High blood pressure (to be given alone or in combination with other antihypertensive drugs)
• Sodium (salt) and fluid retention linked with congestive heart failure.

Indapamide inhibits sodium absorption in the kidneys, causing the sodium to be excreted into the urine. As sodium is excreted, it takes with it fluid from the blood, decreasing the amount of fluid volume in the veins and arteries, thus, lowering the blood pressure.

Generally, thiazide diuretics such as indapamide are not as potent as other types of diuretics (such as various types of loop diuretics). Indapamide is recommended for the treatment of high blood pressure, as a stand-alone medication, or in combination with other antihypertensive medications.

Indapamide is also given to treat excess fluid associated with congestive heart failure. Heart failure is known to cause fluid retention (edema) and indapamide helps to reduce the amount of this excess fluid from the body.

Off-Label Uses 

Sometimes indapamide is used for the treatment of swelling and fluid retention caused by conditions other than congestive heart failure. This would be considered an off-label use of the drug.

Be sure to consult with your healthcare provider or pharmacist about the use of indapamide to treat conditions other than high blood pressure or heart failure.

Before Taking

Before taking indapamide it’s important to:

• Inform your healthcare provider of any medical conditions you currently have, particularly if you have or have had in the past, problems with your heart rhythm, gout, kidney or liver disease, thyroid problems, or parathyroid disease.
• Tell your healthcare provider if you are pregnant or plan to become pregnant or if you are breastfeeding.
• Give your healthcare provider a complete list of any medications you currently take. This includes prescription medications as well as over-the-counter drugs, herbal and natural preparations (including vitamins), and topical creams, lotions, gels, or patches.
• Inform your surgeon or dentist if you are having surgery (or a surgical dental procedure) while taking indapamide. 

Precautions and Contraindications

There are several important considerations to be made before your healthcare provider prescribes indapamide and safety measures to take when you are given this drug.

Diabetes

Careful monitoring should be implemented in those with diabetes. Long-term use of thiazide diuretic treatment was found to lead to glucose intolerance. Indapamide is thought to have the potential to precipitate type 2 diabetes in some instances.

However, in the ADVANCE trial, a combination of indapamide and perindopril (a calcium blocker) was studied in patients with longstanding type 2 diabetes. This combination resulted in lower blood pressures, and a reduced risk of cardiovascular events and mortality.

But another type of thiazide (chlorthalidone) was found to help lower the incidence of cardiovascular events in older people with diabetes who had a specific type of hypertension.

Thiazides are sometimes given when a person has diabetes, but blood and urine glucose levels should be monitored regularly. Your diabetic medication dosage, diet, or exercise regimen may need to be adjusted while you are taking indapamide.

Older Adults

Caution should be used in those who are elderly. Studies show that cases of hyponatremia (low blood sodium level) and hypokalemia (low blood potassium level) occurred in geriatric patients, but these incidents were dose-related. The dosage should be lower in those who are elderly.

Thyroid or Liver Conditions

Indapamide should be used with caution in people with thyroid disease because the drug has the potential to lower iodine levels.

Indapamide is metabolized in the liver, therefore a dosage reduction may be required for those with liver disease or cirrhosis of the liver. Also, sudden changes in electrolyte or fluid imbalance could precipitate a hepatic coma in people with chronic liver disease.

Diet and Lifestyle

Indapamide may cause dizziness and drowsiness. Do not drive a car or operate heavy machinery when taking indapamide. Alcohol can worsen the drowsiness effects of this drug. Do not drink alcohol while taking indapamide.

A special diet (such as a low-sodium diet) may be ordered for those taking indapamide. You may be encouraged to eat foods rich in potassium (such as raisins, prunes, bananas, or orange juice). A potassium supplement may be given to help overcome the potassium loss that occurs when taking indapamide.

Be aware that some types of salt substitutes contain potassium. Do not use these products without the approval of your healthcare provider. If you are taking potassium supplements, these products could cause your potassium level to be too high, which could result in dangerous side effects.

Indapamide can increase calcium in the blood, if you take calcium, vitamin D supplements, or antacids that contain calcium, you may need your calcium levels monitored closely.

Drink plenty of fluids while taking indapamide to help prevent dehydration from fluid loss (unless your healthcare provider instructs you otherwise).

Be aware that indapamide could cause an increase in sun sensitivity. Avoid tanning booths and sunlamps and limit your exposure to direct sun while taking indapamide.

Contraindications

A contraindication is a specific situation in which a drug, treatment, or procedure should not be administered because it has a high potential to cause harm. Contraindications for indapamide include:

• A known allergy to indapamide or to other drugs derived from sulfonamide: These include Bactrim or Septra (trimethoprim and sulfamethoxazole).
• Pregnancy or breastfeeding: The safety of indapamide has not been established in people who are pregnant or breastfeeding.
• Pediatrics: The safe use of indapamide has not been established in children.
• Hypotension (low blood pressure): Indapamide can potentiate symptoms of orthostatic hypotension, increasing the risk of falls, particularly for elderly people. Any type of condition involving low blood pressure should be corrected before indapamide is given, including hypovolemia (low blood volume levels).
• Syncope (fainting caused by a reduction of blood flow to the brain): Indapamide can worsen symptoms of syncope, which can pose an increase in the risk of falls, particularly in elderly people. 
• Post endoscopic thoracic sympathectomy (ETS): This surgical procedure removes part of the sympathetic nerve. It is done for conditions such as hyperhidrosis or facial blushing. In post-ETS patients, indapamide’s antihypertensive effects may be enhanced, causing the blood pressure to be too low.
• Kidney disease: Studies have found that thiazides are ineffective in the late stage of kidney failure (such as stage 4 chronic kidney failure). Indapamide may result in hypovolemia (low blood volume) that could precipitate kidney damage in people with kidney disease.
• Oliguria/anuria: Low urine output/no urine output may be a sign of kidney dysfunction. Those with oliguria or anuria should not take diuretics until the underlying cause of low urine output is treated and remedied.
• Gout: Gout involves high levels of uric acid in the blood that then form uric acid crystals in joints. Indapamide causes an increase in blood urate (uric acid) concentrations. Therefore it should be used with extreme caution, if at all, in those with a history of gout or hyperuricemia.
• Electrolyte imbalances: Any electrolyte imbalances must be corrected before indapamide is given. Careful monitoring of electrolytes is important during the duration of treatment with thiazides.

Other Thiazide Diuretics

Other drugs which are considered thiazide diuretics include:

• Diuril (chlorothiazide)
• Hygroton (chlorthalidone)
• Esidrix, HydroDiuril, Microzide (hydrochlorothiazide)

Dosage

Indapamide tablets are available containing 1.25 milligrams (mg) or 2.5 mg of indapamide.

High Blood Pressure

The average starting dosage of indapamide for high blood pressure is 1.25 mg one time per day. Studies show that severe hyponatremia does not occur when the dose is 1.25 mg daily.

The risk of hyponatremia increases as the dose is raised to 2.5 to 5 mg per day. Therefore, the starting dose should be 1.25 mg and the dosage should be kept at the lowest possible dose.

If a dosage of 1.25 mg per day is not working to lower the blood pressure within the normal range after four weeks, the dose may be increased to 2.5 mg once per day.

If the dosage of 2.5 mg is not effective, adding another antihypertensive medication should be considered, but, a dosage of 5.0 mg, once per day could be given. Dosages of more than 5 mg per day of indapamide have not been studied enough to prove safety or efficacy.

Edema from Congestive Heart Failure

For adults with edema from congestive heart failure, the starting dose of indapamide is 2.5 mg as a single dose to be taken each morning. After a week, if the response is not satisfactory, the dosage can be raised to 5 mg per day, in a single dosage, taken each morning.

Modifications

If indapamide is ineffective for the treatment of high blood pressure, it may be combined with other antihypertensive drugs, but very close monitoring of the blood pressure is required. The normal dosage of the second antihypertensive agent should be lowered by 50%, during the initial combination drug treatment, according to the product label.

How to Take and Store

Indapamide is an oral (by mouth) tablet that is usually ordered once per day, in the morning. It can be taken with or without food. Follow the directions on the label, exactly as they are written.

Be sure to talk to your healthcare provider or pharmacist if you don’t understand any part of the label’s instruction. Take the medication exactly as prescribed.

Do not stop taking indapamide abruptly without consulting with the prescribing healthcare provider. The medication controls your blood pressure while you are taking it, but it doesn’t cure hypertension (high blood pressure). Even if you feel completely cured, you should not stop taking your medication.

If you miss a dose, take it as soon as you remember; but if it’s close to the next time a dose is due (such as the next morning for most people who take indapamide once a day), do not double up to make up for the dose you missed. Doubling up on the medication could cause severe and dangerous side effects.

Keep the medication in the original container, labeled by the pharmacy. Make sure the cap stays tightly closed and store the bottle at room temperature, away from excessive heat or moisture (do not store in the bathroom).

Side Effects

Common Side Effects

Frequent urination, the most common side effects of indapamide, often lasts for approximately six hours after taking a dose and should subside within a few weeks after beginning a drug regime of this medication. Other common side effects include:

• Muscle cramps
• Dizziness
• Confusion
• Fatigue or weakness
• Lethargy (extreme sleepiness and low energy level)
• Cramps or spasms of the muscles

If these symptoms are severe or don’t go away, be sure to contact your healthcare provider.

Other symptoms may include:

• Excessive thirst
• Nausea, stomach cramps, and vomiting
• Low libido (sexual drive and ability)
• Blurred vision

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your healthcare provider or pharmacist.

Severe Side Effects

Severe side effects warrant seeking immediate emergency medical care (such as a visit to the hospital emergency room) these include:

• A rapid, excessive loss of weight
• A severe skin rash and itching
• Difficulty breathing or swallowing

Warnings and Interactions

If you begin vomiting while taking indapamide, it’s important to contact your healthcare provider as soon as possible. Vomiting can increase the risk of dangerous side effects.

Black Box Warnings

Thiazide diuretics can cause severe fluid and electrolyte imbalances such as hyponatremia (low sodium levels in the blood) and hypokalemia (low potassium levels in the blood), as well as hypochloremic alkalosis (a condition caused by low chloride levels). These are serious conditions that could be fatal.

Regular monitoring of electrolytes (such as sodium and potassium) is important. It’s particularly vital for close observation of electrolyte levels in those at high risk of hypokalemia, such as those with cardiac arrhythmias or those who are taking cardiac glycosides (like Lanoxin) while taking thiazides.

Signs of fluid and electrolyte imbalance, which could occur while taking indapamide include:

• Extreme thirst
• Dry mouth
• Weakness
• Oliguria (decreased urination) 
• Muscle cramps or pains
• Low blood pressure
• Tachycardia (fast heart rate)
• Weakness and fatigue
• Gastrointestinal (stomach and intestines) disturbances

If you begin vomiting frequently or are receiving parenteral (IV) fluids, these symptoms should be monitored very closely, along with tests to measure the electrolyte and fluid balance in the body.

Drug Interactions

Drugs that adversely interact with indapamide, and should not be given at the same time as indapamide, include:

• Other antihypertensive drugs: These should only be given with the approval of the prescribing healthcare provider.
• Digoxin (digitalis): This drug is given to strengthen the heart rate. The response from digitalis may be increased if hypokalemia develops from taking thiazide antihypertensive medications.
• Lithium: Diuretics should not be given with lithium because they lower lithium’s renal (kidney) clearance level, which could result in lithium toxicity.
• Corticosteroids (such as prednisone): There is an increased risk of hypokalemia because corticosteroids also have the potential to lower potassium levels in the blood.
• NSAIDs such as Indocin (indomethacin), Advil, Motrim (ibuprofen), Aleve (naproxen), and others
• Benemid (probenecid): Indapamide will increase the effect of probenecid.

There are many other drugs that interact with indapamide, be sure to make a complete list of all medications or supplements you are taking, to give to the prescribing healthcare provider, before starting on indapamide.