**5. Canrenoate**

Canrenone (Figure 1) is one of the two metabolites of spironolactone. It is administered orally as a potassium salt (potassium canrenoate) that is mineralocorticoid receptor-inactive, but it is rapidly transformed to canrenone. Canrenone is water soluble, and this characteristic permits intravenous administration when a rapid effect is desired.

Potassium canrenoate exerts its hypotensive effect approximately one week after the starting dose. Both canrenone and canrenoate are rapidly absorbed (approximately 80%) after oral administration. Both agents have important plasma protein binding (approximately 90%) with small volumes of distribution.
