Prescription Refills, Part-Fills and Intervals


Legislative References:

A fact sheet summarizes relevant legislation in one place. Registrants are reminded to refer to legislation for full context.

Additional references:


Controlled substance: A drug named in the federal Controlled Drug and Substances Act (CDSA), Schedules I, II, III, IV, V. Drugs are also listed in the schedules to the regulations as either narcotics, controlled drugs, benzodiazepines or other targeted substances.


Federal legislation establishes when refills are permitted on a prescription. Regulations for prescription drugs and controlled substances state how the prescriber must give the direction to refill a prescription. Regulations require the date and quantity dispensed of each refill to be indicated on the original prescription (or copy thereof) or in the patient record.

Prescription drugs (Food and Drug Regulations, C.01.042)

  • A pharmacy professional shall not refill a prescription for a drug on the Prescription Drug List unless authorized by the prescriber and no more than the number of times specified by the practitioner.

Narcotics (Narcotic Control Regulations, s. 37)

  • A pharmacist must not use a prescription to dispense a narcotic after the quantity of the narcotic specified in the prescription has been dispensed.
  • See Part-Fills (below)

Controlled drugs (Food and Drug Regulations, G03.006)

  • A pharmacist shall not refill a prescription for a controlled drug unless the prescriber, at the time the prescription is issued, directed that the prescription be refilled.
  • The prescriber must indicate the number of times that it may be refilled and the dates for or the intervals between refills.
  • See Intervals (below)

Benzodiazepines and Other Targeted Substances (Benzodiazepines and Other Targeted Substance Regulations, s52, 53)

  • A pharmacist may only refill a prescription for a targeted substance if the prescriber expressly directs that the prescription may be refilled and specifies the number of refills.

A prescription for any class of drug may be part-filled. A part-fill may be described as dispensing a quantity of drug which is less than the total amount of the drug specified by a prescriber. Part-filling may occur as a result of:

  • A direction given by the prescriber at the time the prescription is issued.
  • Dealing with an inventory shortage or other situations where the nature of the part-fill is a matter of discussion between the pharmacist and patient.
  • A request by the patient or their agent.
    • The Drug Interchangeability and Dispensing Fee Act (DIDFA), s 9, stipulates that a pharmacy professional “shall dispense the entire quantity of the drug prescribed at one time…unless the person presenting the prescription in writing authorizes the dispensing of the drug in smaller quantities.”
    • R.R.O. 1990, Reg. 936, s 3, permits the dispensing of smaller quantities when:
      • There is a limit on the amount or a lesser quantity being paid for by a patient’s private insurance plan or the public Ontario Drug Benefit program.
      • It is necessary and in the patient’s best interest, based on the pharmacist’s professional judgment. Documentation of the pharmacist’s assessment and rationale for the decision is important.
  • Subsequent part fills must be cross-referenced to the original prescription authorization.[1]


Since a prescription for a narcotic drug cannot be refilled, part-fills are used to dispense in smaller amounts of the total quantity prescribed at a time:

  • This supports appropriate opioid therapy such as by facilitating the monitoring of a patient’s pain, minimizes the risk of diversion, loss or theft, etc.
  • The prescription can no longer be filled once the total quantity prescribed has been dispensed and the patient will require a new prescription.
  • The total quantity must be specified (or can be precisely calculated from the mitte quantity prescribed and sig instructions) and not expressed as a lesser quantity multiplied by a number
    • If a prescriber issues a narcotic prescription with a specified quantity plus a number of refills, only the initial specified quantity may be filled; the refills may not.
  • A prescriber may indicate a time interval between, or dates for, refills or part-fills to be dispensed
    • Intervals are only required for refills of controlled drugs, but may be specified by the prescriber on any prescription, especially where drug monitoring is important (e.g. a patient is at risk of opioid use disorder, etc.)
    • If an interval is specified, the next refill or part-fill may be dispensed after the time frame indicated has elapsed.
  • Where patients are early on an interval, the prescriber must be contacted.
    • If the prescriber is not available the pharmacist may use their professional judgment to dispense some or all of the next refill/part-fill.
    • Reasons for the decision must be documented on the patient record.
  • Interval changes or early refills authorized by the prescriber may be accepted verbally and documented.

Published: March 2012
Version #: 2.00

College Contact: Pharmacy Practice

Revision History


Version # Date Action
1 March 2012
  • Published as “Narcotic Prescription Part-Fills”
1.1 March 2020
  • Added temporary CDSA exemption information
2 October 2021
  • Changed title toPrescription Refills, Part-Fills and Intervals”
  • Revised to include all federal drug schedules


  1. Health Canada Bureau of Dangerous Drugs Bulletin to Pharmacists No.3 November 1981