Some medications require good kidney function. During sick days or periods of dehydration they should be stopped to preserve the kidneys. Stop for 3 days and see if illness improves - keep stopped if fluid intake is not enough
OSCE stations could sneakily ask you write up a drug chart for a dehydrated patient which includes some of these drugs which you would be expected to recognised and stop.
MAND
Metformin - dehydration increases the risk of lactic acidosis ACEi/ARBs - impair kidney function NSAIDs - impair kidney function, may cause fluid retention Diuretics - worsen dehydration