No-Substitution Directories
Apr 1993 Council Report

Reacting to the increased incidence of the use of the preprinted "No Sub" directions on prescriptions by the prescribers, and the subsequent dialogue with OCP and the Ministry of Health, the Ontario Medical Association and the College of Physicians and Surgeons of Ontario have advised physicians that they indicate in their own handwriting a "No Sub" direction when, in their professional judgement, it is inappropriate for product selection of a prescription to take place.

If physicians wish to ensure that a specific product be dispensed, they should indicate so on the prescription by writing "No Sub" immediately after the name of each product for which they desire no substitution. The information provided physicians in this matter is essentially a reaffirmation of the policy agreed to by pharmacy and medicine over the years ago, when product selection legislation was introduced. Preprinted instructions on prescriptions are considered inappropriate, because the pharmacist often cannot determine the intention of the prescriber who has used this type of prescription pad.