From the Guidelines
No washout period is required when switching from an ACE-I to an ARB, as the mechanisms of action are different and the switch can be made directly, with monitoring for adequate blood pressure control and potential side effects. When considering the switch, it's essential to understand the patient's current condition, the reason for switching, and to monitor them closely after the change. The primary concern with switching between these classes of medications is not the washout period but ensuring that the patient does not experience a significant drop in blood pressure or other adverse effects. According to the guidelines 1, the focus is on the benefits of ACE inhibitors and ARBs in reducing morbidity and mortality in patients with heart failure, rather than the specifics of switching between them. However, it's crucial to note that when switching to an ARNI (Angiotensin Receptor-Neprilysin Inhibitor) from an ACE-I, a 36-hour washout period is recommended due to the risk of angioedema 1.
Key points to consider when switching from an ACE-I to an ARB include:
- Monitoring blood pressure closely after the switch to ensure the ARB is effective.
- Being aware of potential side effects such as dizziness or hypotension, especially in the initial period after switching.
- Adjusting the dose of the ARB as necessary based on the patient's response.
- Considering the individual patient's condition and the reason for the switch, whether it be due to side effects from the ACE-I or the need for better blood pressure control.
It's also important to recognize that the decision to switch should be based on the individual patient's needs and response to medication, rather than a one-size-fits-all approach. The guidelines 1 emphasize the importance of tailoring treatment to the patient, including the choice between ACE inhibitors and ARBs, based on their specific clinical profile and history.
From the FDA Drug Label
7.4 Dual Blockade of the Renin-Angiotensin System (RAS) Dual blockade of the RAS with angiotensin receptor blockers, ACE inhibitors, or aliskiren is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function (including acute renal failure) compared to monotherapy
The FDA drug label does not provide information on the need for a washout period when switching from an ACE-I to an ARB. However, it does warn against the dual blockade of the RAS with angiotensin receptor blockers and ACE inhibitors due to increased risks of adverse effects.
- Key points:
- Dual blockade of the RAS is associated with increased risks
- No information is provided on washout periods 2
From the Research
Switching from ACE-I to ARB
- The study 3 found that switching from an ACEI to an ARB (losartan) is safe and effective, with no significant increase in adverse events.
- The CORD IA trial 3 showed that patients who switched from an ACEI to losartan had a significant decrease in blood pressure, with no changes in plasma sodium, potassium, urea, or creatinine.
- However, the study 4 investigated the adherence to a 36-hour washout period when switching from ACEI to ARNI (angiotensin receptor/neprilysin inhibitor) and found that 67% of patients received the full washout period, with no significant differences in hospital readmissions or adverse effects between the groups.
Washout Period
- The study 4 recommended a 36-hour washout period when switching from ACEI to ARNI due to an increased risk of adverse effects, including angioedema.
- However, the studies 3, 5, 6, and 7 do not provide evidence for a specific washout period when switching from ACEI to ARB.
- The study 5 suggests that ARBs may be a better option than ACEIs due to fewer adverse events, but does not address the issue of a washout period.
Adverse Events
- The study 3 found that switching from an ACEI to an ARB (losartan) did not significantly increase the rate of adverse events.
- The study 5 found that ACEIs are associated with cough and a very low risk of angioedema and fatalities, while ARBs have fewer adverse events.
- The study 4 found no significant differences in adverse events, including angioedema, hypotension, acute kidney injury, and hyperkalemia, between patients who received a 36-hour washout period and those who did not.