TIW

Medical abbreviation · Prescription

TIW
Stands forThree times a week
CategoriesMedical

TIW stands for Three times a week, a prescription abbreviation.

Weekly dosing schedule for drugs given on three nonconsecutive days, such as some interferon products, dialysis-session medications and certain antibiotics for tuberculosis. ISMP lists it as error-prone because it has been read as "three times a day" or "twice in a week".

Example: Epoetin alfa 4,000 units IV TIW with hemodialysis.

Usage notes

Also written tiw or t.i.w. ISMP recommends "3 times weekly", ideally naming the days (e.g. Monday, Wednesday, Friday). Misreading TIW as TID would give seven times the intended weekly dose, a serious risk with drugs such as methotrexate or interferons.

More prescription abbreviations

  • aa – Ana (of each)
  • AC – Ante cibum (before meals)
  • ACHS – Ante cibum et hora somni (before meals and at bedtime)
  • ad lib. – Ad libitum (at one's pleasure)
  • ATC – Around the clock
  • bd – Bis die (twice a day)
  • BID – Bis in die (twice a day)
  • BIW – Twice a week
  • BT – Bedtime
  • cc – Cubic centimeter
  • c̄ – Cum (with)
  • D/C – Discontinue

See all 77 prescription abbreviations →

Edited by the AbbreviationList.com team. Spotted an error or a missing meaning? Contact us.

This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.