, hyperkalemia) the patient cannot tolerate the maximum dose, a smaller dose may still be reasonable. It should be noted that the maximum dose of RASi allowed by the regulatory agency varies by country, and the practitioners are advised to follow their respective national guidance. Practice Point 3.2.3: Changes in BP, serum creatinine, and serum potassium should be checked within 2 4 weeks of initiation or increase in the dose of a RASi, depending on the current GFR and serum potassium. ACEi and ARBs are potent antihypertensive agents that counteract the vasoconstrictive effects of angiotensin II. Moreover, blocking the action of angiotensin II causes selec- tively greater vasodilatation of the efferent arterioles of the glomeruli, resulting in a decline of the intraglomerular ltra- tion pressure, and not unexpectedly, a decrease in the GFR and a rise in the serum creatinine. In addition, RAS blockade in- hibits the action of aldosterone, resulting in a greater pro- pensity for hyperkalemia. In patients at risk for hyperkalemia, measuring serum potassium before and at 1 2 weeks after initiation of RASi is recommended, based on expert opinion.44 An increase in serum creatinine level, if it occurs, will typically happen during the rst 2 weeks of treatment initiation, and it should stabilize within 2 4 weeks in the setting of normal so- dium and uid intake.263 Therefore, patients should be monitored for symptomatic hypotension, hyperkalemia, and serum creatinine within 2 4 weeks after initiating or changing the dose of the drug, with the time interval depending on baseline BP, serum creatinine, and serum potassium. A shorter time interval is indicated if the baseline serum creatinine is high, or serum potassium is already high-normal, or there is a history of hyperkalemia or an acute rise in serum creatinine with BP lowering or RASi. 