medications_remaining: Calculate remaining medications to be taken

In pregnancy: Calculate and Track Dates and Medications During Pregnancy

Calculate remaining medications to be taken

Description

Calculates and displays how many medications remain to be taken as of a specific date, based on a schedule of medications with start and stop dates. Results can be grouped either by medication name or by format (e.g., tablet, injection).

Usage

medications_remaining(
  meds = NULL,
  group = c("medication", "format"),
  on_date = Sys.Date(),
  until_date = NULL
)

Arguments

meds	Data frame containing medication schedule. Must have the following columns: medication (character/factor): Name of the medication format (character/factor): Format of the medication (e.g., pill, injection) quantity (numeric): Number of units to take per day start_date (Date or character string representing a date, e.g. "YYYY-MM-DD"): Date to start taking the medication stop_date (Date or character string representing a date, e.g. "YYYY-MM-DD"): Final date on which the medication is taken If NULL, will try to use the "pregnancy.medications" option. Required if option not set.
group	Character string specifying how to group the results. One of: "medication": Group by medication name (default) "format": Group by medication format
on_date	Date or character string representing a date, e.g. "YYYY-MM-DD", specifying the date from which to calculate remaining medications. Defaults to current system date
until_date	Date or character string representing a date, e.g. "YYYY-MM-DD", specifying cut-off date for remaining medications. If NULL, defaults to the latest stop_date in medications.

Details

If on_date, until_date start_date or stop_date is a character vector, the conversion to a Date is handled by anytime::anydate().

If any start_date is NA in any row, that row will not be counted in the remaining quantities. If any stop_date is NA, it throws an error.

Value

Returns a data frame containing remaining quantities, grouped as specified. Assumes that the function is being called first thing in the day, i.e. before any of on_date's medications have been taken. The data frame has two columns:

• Either 'medication' or 'format' depending on grouping

• quantity: Total number of units remaining

Only medications with remaining quantities > 0 are included.

If no medications remain, a message is printed to the console indicating this, and a data frame with 0 rows is returned invisibly.

Global Options

• pregnancy.medications: Data frame setting default medication schedule

See Also

• set_medications() for setting default medication schedule

• get_medications() for retrieving current medication schedule

• medications for an example medications data frame

Examples

# Define medications table
#' # Create example medication schedule
meds <- data.frame(
  medication = c("progynova", "prednisolone", "clexane"),
  format = c("tablet", "tablet", "injection"),
  quantity = c(3, 2, 1),
  start_date = c("2025-04-21", "2025-04-26", "2025-05-08"),
  stop_date = c("2025-04-30", "2025-05-07", "2025-09-05")
)

# Calculate remaining medications
medications_remaining(meds, on_date = "2025-04-21")

medications_remaining(meds, group = "format", on_date = "2025-04-21")

# Calculate medications for a specified period
medications_remaining(
  meds = meds,
  on_date = "2025-04-23",
  until_date = "2025-04-30"
)

# Set and use global medications option
#' Store original medications setting (without message)
original_medications <- getOption("pregnancy.medications")
set_medications(pregnancy::medications)
medications_remaining(on_date = as.Date("2025-05-01"))

# Restore original medications setting (without message)
options(pregnancy.medications = original_medications)

pregnancy documentation built on Sept. 14, 2025, 5:09 p.m.