Sometimes it may be necessary to reduce a patient's drug dose over time. Examples include opioids for pain or corticosteroids.
Parameters:
(1) starting dose
(2) final dose (same units as starting dose)
(3) percent decrease for each interval
(4) length of each interval in days
decimal fraction of original dose at target =
= (final dose) / (starting dose)
decimal fraction of original dose at each interval =
= (100 - (percent decrease each interval)) / 100
decimal fraction of original dose at target =
= (decimal fraction of original dose at each interval) ^ (number of intervals)
number of intervals =
= LN(decimal fraction at target) / LN(decimal fraction of original dose at each interval)
total time to reach final dose =
= (number of intervals) * (length of each interval in days)
