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A component of the Canadian Medication Incident Reporting and Prevention System (CMIRPS).

SafeMedicationUse Newsletter

Caution: Not All Medicines Are Taken Every Day


Have you ever been given a medicine that should be taken once a week or 3 times a week or once a month or on some other irregular schedule? Although many medicines are taken every day, other medicines are taken less frequently. received a report about a mix-up between 2 medicines that were meant to be taken on different schedules.

The story

An older adult consumer was taking a medicine called atorvastatin to treat her high cholesterol. She was also taking another medicine, risedronate, for osteoporosis. The atorvastatin was to be taken once a day, and the risedronate was to be taken only once a week. The consumer confused the medicines and started taking the risedronate daily, thinking it was atorvastatin. This error was discovered at the pharmacy when the consumer requested a refill of the risedronate much earlier than expected.

What's the harm?

Fortunately, no harm came to the consumer in this case. However, the result might have been different if the error had continued for a longer period of time or if the error had involved a different medicine that carried more risk of harm from side effects or overdose.

The Institute for Safe Medication Practices Canada (ISMP Canada) has previously received reports of a similar mistake with a medicine called methotrexate. This medicine is often prescribed to be taken once a week to treat rheumatoid arthritis. However, some patients have mistakenly taken it once a day. These cases have resulted in severe harm, including lung damage, liver damage, infections, and even death. To avoid harm from this type of mistake, it is very important to know how often to take each of your medicines. Make note of any medicines that are not to be taken every day.

What can I do to prevent this problem? has the following suggestions:

  • Whenever you receive a prescription for a new medicine, review the details with your prescriber and your pharmacist. Make sure you know the name of the medicine, the strength, and how often you should take it.
  • It can be difficult to remember the timing for medicines that are not taken every day. Mark your calendar, or set up a reminder on your mobile device, perhaps using a reminder app.
  • If you take many different medicines and you find it hard to keep track of the dosing schedules, consider asking your pharmacist for a pill organizer, also called a dosette or talk to your pharmacist about having your medicines prepared in blister packs. The pharmacy can arrange your medicines by day and time to make it easier to follow the correct schedule.
  • Find a way to tell apart the medicines that are not taken every day. For example:
    • Mark each medicine vial with a different colour.
    • Store different medicines in separate locations (or in separate bins in the same location) to prevent a mix-up.
  • Ask your pharmacist if you are eligible for a medication review. In this type of review, the pharmacist will check all the medicines you are taking and discuss them with you.

Tips for Practitioners:

  • When prescribing or dispensing new medicines that have an unusual dosing schedule, make sure that the patient is aware of the schedule.
  • Investigate the reasons for early refill requests. Has there been a change in therapy? Is the consumer going on vacation? Might the consumer be taking their medicine incorrectly?
  • Ask patients to bring their medicine vials when coming for a medication review. Having the vials on hand will help you to ensure that the medications are in appropriately labelled bottles or compliance packaging and that patients are taking them correctly.

Medication Safety bulletins contribute to Global Patient Safety Alerts

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