Indapamide

FDA Drug Information • Also known as: Indapamide

Brand Names: Indapamide
Drug Class: Thiazide-like Diuretic [EPC]
Route: ORAL
Dosage Form: TABLET
Product Type: HUMAN PRESCRIPTION DRUG

Description

Indapamide is an oral antihypertensive/diuretic. Its molecule contains both a polar sulfamoyl chlorobenzamide moiety and a lipid-soluble methylindoline moiety. It differs chemically from the thiazides in that it does not possess the thiazide ring system and contains only one sulfonamide group. The chemical name of indapamide is 4-Chloro-N-(2-methyl-1-indolinyl)-3-sulfamoylbenzamide, and its molecular weight is 365.84. The compound is a weak acid, pKa=8.8, and is soluble in aqueous solutions of strong bases. It is a white to yellow-white crystalline (tetragonal) powder. [structure] C16H16ClN3O3S Each tablet, for oral administration, contains 1.25 mg or 2.5 mg of indapamide USP and the following inactive ingredients: corn starch, hypromellose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, talc, and titanium dioxide. Additionally, the 1.25 mg product contains FD&C yellow #6 aluminum lake.

What Is Indapamide Used For?

Indapamide tablets are indicated for the treatment of hypertension, alone or in combination with other antihypertensive drugs. Indapamide tablets are also indicated for the treatment of salt and fluid retention associated with congestive heart failure. Usage in Pregnancy The routine use of diuretics in an otherwise healthy woman is inappropriate and exposes mother and fetus to unnecessary hazard (see PRECAUTIONS). Diuretics do not prevent development of toxemia of pregnancy, and there is no satisfactory evidence that they are useful in the treatment of developed toxemia. Edema during pregnancy may arise from pathological causes or from the physiologic and mechanical consequences of pregnancy. Indapamide is indicated in pregnancy when edema is due to pathologic causes, just as it is in the absence of pregnancy (however, see PRECAUTIONS). Dependent edema in pregnancy, resulting from restriction of venous return by the expanded uterus, is properly treated through elevation of the lower extremities and use of support hose; use of diuretics to lower intravascular volume in this case is illogical and unnecessary. There is hypervolemia during normal pregnancy which is not harmful to either the fetus or the mother (in the absence of cardiovascular disease), but which is associated with edema, including generalized edema in the majority of pregnant women. If this edema produces discomfort, increased recumbency will often provide relief. In rare instances, this edema may cause extreme discomfort which is not relieved by rest. In these cases, a short course of diuretics may provide relief and may be appropriate.

Dosage and Administration

Hypertension The adult starting indapamide dose for hypertension is 1.25 mg as a single daily dose taken in the morning. If the response to 1.25 mg is not satisfactory after 4 weeks, the daily dose may be increased to 2.5 mg taken once daily. If the response to 2.5 mg is not satisfactory after 4 weeks, the daily dose may be increased to 5 mg taken once daily, but adding another antihypertensive should be considered. Edema of Congestive Heart Failure The adult starting indapamide dose for edema of congestive heart failure is 2.5 mg as a single daily dose taken in the morning. If the response to 2.5 mg is not satisfactory after one week, the daily dose may be increased to 5 mg taken once daily. If the antihypertensive response to indapamide is insufficient, indapamide may be combined with other antihypertensive drugs, with careful monitoring of blood pressure. It is recommended that the usual dose of other agents be reduced by 50% during initial combination therapy. As the blood pressure response becomes evident, further dosage adjustments may be necessary. In general, doses of 5 mg and larger have not appeared to provide additional effects on blood pressure or heart failure, but are associated with a greater degree of hypokalemia. There is minimal clinical trial experience in patients with doses greater than 5 mg once a day.

Side Effects (Adverse Reactions)

Most adverse effects have been mild and transient. The clinical adverse reactions listed in Table 1 represent data from Phase II/III placebo-controlled studies (306 patients given indapamide 1.25 mg). The clinical adverse reactions listed in Table 2 represent data from Phase II placebo-controlled studies and long-term controlled clinical trials (426 patients given indapamide 2.5 mg or 5 mg). The reactions are arranged into two groups: 1) a cumulative incidence equal to or greater than 5%; 2) a cumulative incidence less than 5%. Reactions are counted regardless of relation to drug. TABLE 1: Adverse Reactions from Studies of 1.25 mg Incidence ≥ 5% Incidence < 5%1 BODY AS A WHOLE Headache Infection Pain Back Pain Asthenia Flu Syndrome Abdominal Pain Chest Pain GASTROINTESTINAL SYSTEM Constipation Diarrhea Dyspepsia Nausea METABOLIC SYSTEM Peripheral Edema CENTRAL NERVOUS SYSTEM Dizziness Nervousness Hypertonia RESPIRATORY SYSTEM Rhinitis Cough Pharyngitis Sinusitis SPECIAL SENSES Conjunctivitis 1 OTHER All other clinical adverse reactions occurred at an incidence of < 1%. Approximately 4% of patients given indapamide 1.25 mg compared to 5% of the patients given placebo discontinued treatment in the trials of up to 8 weeks because of adverse reactions. In controlled clinical trials of 6 to 8 weeks in duration, 20% of patients receiving indapamide 1.25 mg, 61% of patients receiving indapamide 5 mg, and 80% of patients receiving indapamide 10 mg had at least one potassium value below 3.4 mEq/L. In the indapamide 1.25 mg group, about 40% of those patients who reported hypokalemia as a laboratory adverse event returned to normal serum potassium values without intervention. Hypokalemia with concomitant clinical signs or symptoms occurred in 2% of patients receiving indapamide 1.25 mg. TABLE 2: Adverse Reactions from Studies of 2.5 mg and 5 mg Incidence ≥ 5% Incidence < 5% CENTRAL NERVOUS SYSTEM/NEUROMUSCULAR Headache Dizziness Fatigue, weakness, loss of energy, lethargy, tiredness, or malaise Muscle cramps or spasm, or numbness of the extremities Nervousness, tension, anxiety, irritability, or agitation Lightheadedness Drowsiness Vertigo Insomnia Depression Blurred Vision GASTROINTESTINAL SYSTEM Constipation Nausea Vomiting Diarrhea Gastric irritation Abdominal pain or cramps Anorexia CARDIOVASCULAR SYSTEM Orthostatic hypotension Premature ventricular contractions Irregular heart beat Palpitations GENITOURINARY SYSTEM Frequency of urination Nocturia Polyuria DERMATOLOGIC/HYPERSENSITIVITY Rash Hives Pruritus Vasculitis OTHER Impotence or reduced libido Rhinorrhea Flushing Hyperuricemia Hyperglycemia Hyponatremia Hypochloremia Increase in serum urea nitrogen (BUN) or creatinine Glycosuria Weight loss Dry mouth Tingling of extremities Because most of these data are from long-term studies (up to 40 weeks of treatment), it is probable that many of the adverse experiences reported are due to causes other than the drug. Approximately 10% of patients given indapamide discontinued treatment in long-term trials because of reactions either related or unrelated to the drug. Hypokalemia with concomitant clinical signs or symptoms occurred in 3% of patients receiving indapamide 2.5 mg q.d. and 7% of patients receiving indapamide 5 mg q.d. In long-term controlled clinical trials comparing the hypokalemic effects of daily doses of indapamide and hydrochlorothiazide, however, 47% of patients receiving indapamide 2.5 mg, 72% of patients receiving indapamide 5 mg, and 44% of patients receiving hydrochlorothiazide 50 mg had at least one potassium value (out of a total of 11 taken during the study) below 3.5 mEq/L. In the indapamide 2.5 mg group, over 50% of those patients returned to normal serum potassium values without intervention. In clinical trials of 6 to 8 weeks, the mean changes in selected values were as shown in the tables below. Mean Changes from Baseline after 8 Weeks of Treatment - 1.25 mg Serum Electrolytes (mEq/L) Serum Uric Acid (mg/dL)...

Warnings and Precautions

Severe cases of hyponatremia, accompanied by hypokalemia have been reported with recommended doses of indapamide. This occurred primarily in elderly females. (See PRECAUTIONS, Geriatric Use.) This appears to be dose related. Also, a large case-controlled pharmacoepidemiology study indicates that there is an increased risk of hyponatremia with indapamide 2.5 mg and 5 mg doses. Hyponatremia considered possibly clinically significant (< 125 mEq/L) has not been observed in clinical trials with the 1.25 mg dosage (see PRECAUTIONS). Thus, patients should be started at the 1.25 mg dose and maintained at the lowest possible dose. (See DOSAGE AND ADMINISTRATION.) Hypokalemia occurs commonly with diuretics (see ADVERSE REACTIONS, Hypokalemia), and electrolyte monitoring is essential, particularly in patients who would be at increased risk from hypokalemia, such as those with cardiac arrhythmias or who are receiving concomitant cardiac glycosides. In general, diuretics should not be given concomitantly with lithium because they reduce its renal clearance and add a high risk of lithium toxicity. Read prescribing information for lithium preparations before use of such concomitant therapy.

Contraindications

Anuria. Known hypersensitivity to indapamide or to other sulfonamide-derived drugs.

Overdosage

Symptoms of overdosage include nausea, vomiting, weakness, gastrointestinal disorders, and disturbances of electrolyte balance. In severe instances, hypotension and depressed respiration may be observed. If this occurs, support of respiration and cardiac circulation should be instituted. There is no specific antidote. An evacuation of the stomach is recommended by emesis and gastric lavage after which the electrolyte and fluid balance should be evaluated carefully.

How Supplied

Indapamide Tablets USP are available containing 1.25 mg or 2.5 mg of indapamide USP. The 1.25 mg tablets are orange, round, film coated tablets debossed ‘ANI’ over ‘510’ on one side and plain on the other side. They are available in bottles of 100 tablets (NDC 62559-510-01). The 2.5 mg tablets are white, round, film coated tablets debossed ‘ANI’ over ‘511’ on one side and plain on the other side. They are available in bottles of 60 tablets (NDC 72189-591-60).

About This Information

This drug information is sourced from FDA-approved labeling via the openFDA database. It is intended for educational and reference purposes only. This is not medical advice. Always consult your healthcare provider before making decisions about medication. Drug information may be updated by the FDA; check with your pharmacist for the most current information.

What are side effects?

Side effects are unwanted reactions that can occur when taking a medication. They range from mild (headache, nausea) to severe (allergic reactions, organ damage). Not everyone experiences side effects, and severity varies. Report any concerning side effects to your doctor.

What are drug interactions?

Drug interactions occur when a medication is affected by another drug, food, or supplement. Interactions can make medications less effective or cause dangerous side effects. Always tell your doctor about all medications and supplements you take.