Renoprotection with indapamide, additional feature to look for.

To the Editor,

At the outset I would like to congratulate you for choosing a topic which has even a larger relevance in a country like India. You have rightly pointed out that despite several trials have demonstrated mortality benefit with diuretic therapy in uncomplicated hypertension their use in real world practice is going down. The declining trend in prescription may be related to several misconceptions prevailing about the use of diuretics in primary hypertension. You also recommended that among the available options of diuretics, low dose chlorthalidone and indapamide are preferred because they are less likely to be associated with significant adverse metabolic effects (increased lipid levels, adverse effects on glucose metabolism, effects on arrhythmias, etc.). In this letter, I would like to add a few more points in favor of indapamide in terms of renoprotection and other effects which may boost our confidence on this molecule.

In 1991 Gambardella et al. first published the renoprotective effect of long-term indapamide treatment, defined as a reduction in urinary protein loss in patients with type 2 diabetes and persistent microalbuminuria. Several other reports also claimed the similar effects, some of them stating the drug being as effective as ACEIs.3, 4 These apparent renoprotective effects of thiazide diuretics may be specific to diabetic patients.

Apart from the above mentioned advantages, indapamide is likely to cause less hypokalemia when compared to equivalent doses of chlorthalidone and hydrochlorthiazide. Not only that, indapamide is most effective in terms of nocturnal BP control among all the available diuretic options. These benefits of indapamide are proven at the therapeutic dosage of either 2.5 mg immediate release or the superior 1.5 mg sustained release. The SR formulation avoids unnecessary peak in the plasma level of the drug and ensures that only a subclinical diuresis is there, while indapamide controls BP by its predominantly vascular effect (normalization of hyperreactivity of vasculature to noradrenalin). This minimizes the risk of diuretic related side effects like electrolytic or metabolic disturbances. Indapamide also causes venorelaxation, which explains why the risk of pedal edema is minimized when indapamide is added to amlodipine.

So, I fully agree with you that we should increase our prescriptions of diuretics in uncomplicated primary hypertension. Among the available diuretic options, indapamide is probably having an edge, particularly in diabetic subpopulation.