Drugs Requiring Washout Periods (Safe Switching ) Definition: A washout period is a time interval required when switching certain drugs to prevent adverse interactions or overlapping effects. Practical Points • Cardiovascular drugs rarely need washout except ACE inhibitors → ARNI. • Psychotropics and anticoagulants are the main classes where washout matters. • Always check half-life of the drug — drugs with long half-lives (amiodarone, fluoxetine) require longer washout. | MRCP UK