| Indication | For the treatment of hypertension, alone or in combination with other antihypertensive drugs, as well as for the treatment of salt and fluid retention associated with congestive heart failure or edema from pregnancy (appropriate only in the management of edema of pathologic origin during pregnancy when clearly needed). Also used for the management of edema as a result of various causes. |
| Pharmacodynamics | Indapamide is an antihypertensive and a diuretic. It contains both a polar sulfamoyl chlorobenzamide moiety and a lipid- soluble methylindoline moiety. Indapamide bears a structural similarity to the triazide diuretics which are known to decrease vascular smooth muscle reactivity. However, it differs chemically from the thiazides in that it does not possess the thiazide ring system and contains only one sulfonamide group. Indapamide appears to cause vasodilation, probably by inhibiting the passage of calcium and other ions (sodium, potassium) across membranes. This same effect may cause hypokalcemia in susceptible individuals. Indapamide has also been shown to cause uterine myometrial relaxation in experimental animals. Overall, indapamide has an extra-renal antihypertensive action resulting in a decrease in vascular hyperreactivity and a reduction in total peripheral and arteriolar resistance. |
| Mechanism of action | Indapamide blocks the slow component of delayed rectifier potassium current (IKs) without altering the rapid component (IKr) or the inward rectifier current. Specifically it blocks or antagonizes the action the proteins KCNQ1 and KCNE1. Indapamide is also thought to stimulate the synthesis of the vasodilatory hypotensive prostaglandin PGE2. |
| Absorption | Rapidly absorbed from gastrointestinal tract. |
| Volume of distribution | Not Available |
| Protein binding | 71-79% |
| Metabolism | Primarily hepatic. Indapamide is an extensively metabolized drug with only about 7+ACU- of the total dose administered, recovered in the urine as unchanged drug during the first 48 hours after administration. |
| Route of elimination | Indapamide is an extensively metabolized drug, with only about 7% of the total dose administered, recovered in the urine as unchanged drug during the first 48 hours after administration. |
| Half life | 14 hours (biphasic) |
| Clearance | Not Available |
| Toxicity | Side effects include electrolyte imbalance (potassium or salt depletion due to too much fluid loss), nausea, stomach disorders, vomiting, weakness |