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Medication safety

Close-up of a hand reaching for one of many medication boxes on a shelf.
Published: May 2021
16 minutes


Prescribing and managing medications is a complex interprofessional challenge. Providing patients the medication they require involves many steps, each with its unique risks, whether using paper-based or electronic prescribing systems. Harm can originate at any of the following phases:

  • prescribing the medication
  • transcribing the prescription
  • preparing and dispensing the medication
  • administering the medication
  • monitoring the patient for therapeutic and adverse effects of the medication

Good practice guidance

Provider factors

  • loss of situational awareness
    • due to incomplete patient assessments
      • allergies
      • co-morbidities
      • medical history
      • current medications
      • pertinent laboratory values
    • due to lack of interprofessional communication
      • not reading nursing or pharmacist notes
      • unclear recommendations from consultants
  • failure to consider medication-specific factors
    • indications
    • contraindications and precautions
    • potential interactions with other medication, food, supplements or herbal remedies if known
    • potential adverse effects

Team factors

  • inadequate exchanges (i.e. verbal and written) between providers about changes to medication orders or regarding discrepancies
  • inadequate communication between physicians and other team members
  • inadequate communication with patients, their family or other supports

Patient factors

  • biological factors (overall health, drug sensitivities or allergies, etc.)
  • competing nutritional or over-the-counter products such as drugs and supplements
  • language or cultural barriers
  • adherence to medication regimen
  • patient understanding

System factors

  • inadequate hospital policies for medication management on transfer
  • lack of systems to verify that medications are properly documented, ordered, or transcribed

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Informed consent

Patients are their own best risk managers. They are able to make sound decisions meeting their own needs and preferences if informed of the benefits, alternatives and the material and special risks of the intended medication.

It is important for patients to understand the:

  • nature of the proposed medication therapy
  • anticipated side effects of the proposed treatment and alternatives
  • consequences of refusing treatment

Physicians should take care to document the consent discussion in the medical record and note patient questions and concerns.

Informed discharge

Patients should be informed of the symptoms and signs indicating a need for further care, its urgency, and how to obtain that care. In the context of starting a new medication, it is important to include information about how to recognize and manage a significant side effect that would require re-evaluation. Physicians should document in the medical record the information and instructions provided to the patient.

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Numerous studies have confirmed that enhanced communication and collaborative working relationships between physicians and pharmacists foster better patient care. In some cases, better communication has resulted in patients' increased adherence to drug therapy.1 In others, it has been shown to provide individuals suffering from chronic conditions with greater support so they can improve how they manage their drug therapy.

Pharmacists' work and responsibilities are expanding. Depending on the jurisdiction, pharmacists' additional authority can include the following:

  • prescribing for minor ailments
  • renewing medications
  • changing dosages, formulations, and regimens
  • making therapeutic substitutions
  • providing emergency prescriptions
  • administering injections

In some provinces and territories, pharmacists have the authority to carry out activities independently, while others require physician notification, consultation, or approval. To promote safe care and avoid misunderstandings, it is important for physicians to have a clear understanding, in the context of their own practice, of when pharmacists can act independently, and when they require physician involvement.

As both physicians and pharmacists are independent providers, each owes a separate duty to the patient for care that falls within their individual scopes of practice. This makes evident the need for efficient and effective communication between physicians and pharmacists in the interest of safety. Physicians will generally not be held liable for the actions of a pharmacist when the pharmacist acts independently from the physician within the pharmacist’s own scope of practice. It is possible, however, for a physician and a pharmacist to be held jointly liable if a patient safety incident (accident in Québec) results from a lack of reasonably expected communication between the two for which both are considered responsible in the circumstances.

To allow for an appropriate and efficient response to critical and routine requests from pharmacists, it is important for physicians to determine how communication from pharmacists will be processed and to establish clear procedures for office staff. Having a timely and efficient system for reviewing pharmacists' requests for medication refills, for example, ensures appropriate and safe dispensing.

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Medication-related harm often arises from inadvertent duplication of, omission of, or interactions between medications. Medication reconciliation is a process that involves working with patients, family (with consent), and other healthcare professionals to ensure that accurate and comprehensive medication information, including over-the-counter or non-prescription medication, is communicated across transitions of care.

Since the process involves multiple healthcare professionals (e.g. physician, nurse, pharmacist), effective team communication is essential. Policies and procedures can facilitate the process and physicians should be familiar with their role and responsibilities relative to medication reconciliation.

Patients are members of the healthcare team. Physicians can promote medication safety by involving patients and families in medication reconciliation. When physicians make changes to a patient’s medication, discussing these with the patient, assessing the patient’s understanding, and documenting the change and discussion in the health record are important safeguards that promote safety.

Stages of the medication reconciliation process

Medication reconciliation is important in all settings, including acute care hospitals, long-term care facilities, and community settings like multidisciplinary clinics and home care.

In the hospital setting, the medication reconciliation process should be undertaken at key milestones such as:

  • Admission: Evaluate each of the patient's medications and determine if they should be continued, modified, or discontinued.
  • In-hospital transfer: Evaluate whether the patient's present hospital medications should be continued and whether medications taken at home should be resumed, modified, or discontinued.
  • Discharge: To avoid duplicating, omitting, or prescribing unnecessary medications, cross-reference the patient's pre-admission medication list with the most recent hospital medication list to compare and evaluate the continuing indication and need for all:
    • pre-hospital medications
    • medications started or modified in hospital
    • planned post-discharge medications.

When discharging a patient or transferring their care to another provider, medication reconciliation is an opportunity to identify, investigate and validate any discrepancies.

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Physicians often use medications and devices off-label to treat their patients. Off-label refers to using a prescription pharmaceutical or device approved for sale by Health Canada beyond the criteria set out in the product’s approval. While this may usually mean using a drug or device for an illness or disease not listed in the original authorization, it can also include prescribing different dosages or frequencies, lengthening or shortening the duration of treatments, prescribing to different patient populations (e.g. children) or using different routes of administration than indicated on the drug label.

To minimize the risk when prescribing off-label medication or device use, consider:

  • obtaining a detailed history from patients and examining them to determine if they have a condition that would place them at increased risk of potential side-effects from the off-label use of the drug or device
  • determining if the use is in keeping with current standards of practice
  • having and documenting an appropriate consent discussion of the potential risks and benefits, including a discussion of the fact that the drug or device being considered is not approved for the patient’s particular condition or being used in a manner that differs from the original authorization and broadening the extent of the consent discussion as it pertains to potential risks you might not typically disclose
  • explaining and documenting the rationale for using an off-label medication or device
  • answering and documenting any questions asked by the patient
  • providing information on the symptoms and signs that would warrant additional medical care and where to obtain that care (informed discharge), and documenting that informed discharge discussion
  • carefully monitoring patients receiving off-label medications and devices

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Children are at increased risk for adverse drug events for many reasons that can include:

  • substantial differences in body surface area
  • the need for individualized dosage calculations based on weight
  • immature physiological systems that affect medication absorption, metabolism, and excretion
  • limited safe dosing ranges
  • lack of information on indications and dosing (due, in part, to a lack of clinical trials in children)
  • difficulty communicating the adverse effects of a medication they may be experiencing

The Institute for Safe Medication Practices Canada (ISMP Canada) has identified the top five medications that frequently result in serious adverse drug events in pediatric patients.2

  1. morphine
  2. potassium chloride
  3. insulin
  4. fentanyl
  5. salbutamol

Morphine and fentanyl together are responsible for over half of the adverse drug events attributable to the top five medications.

Liquid formulations are an integral part of pediatric medication administration. While easy, volume-based prescribing is dangerous: liquid formulations often come in a variety of concentrations and making assumptions about the concentration that will be dispensed can lead to harm. Because different circumstances may call for different doses and concentrations of the same medication, prescribing the medication in mg/kg (as opposed to prescribing by volume, in milliliters) while specifying the patient’s bodyweight on the prescription helps minimize over- or under-dosing.

When ordering medications for children consider the following:

  • Are medication reference materials or treatment algorithms readily available and is the information current and clear?
  • Is your prescription legible?
  • Is your use of decimal points clear?
    • Do you use a leading zero before a decimal point for doses that are less than one?
      • this decreases the chance of a 0.2 mg dose, written as .2mg, being misinterpreted as 2 mg
    • Do you avoid using a trailing zero by itself after a decimal point?
      • this decreases the chance of a 5 mg dose, written as 5.0 mg, being misinterpreted as 50 mg
  • Does the prescription contain all of the required elements?
    • this might include noting the weight used to calculate the dose, to allow a pharmacist to verify your calculations
  • Do you determine the appropriate dose of the medication based on the child's weight?
  • Do you avoid prescribing in milliliters?
  • Do you provide clear instructions to the patient (if capable of consenting) or the parent(s) (if patient is incapable of consenting, or with the capable patient’s consent) when an existing prescription is modified?
  • Do you speak directly with the pharmacist if they are inquiring about your prescription (as opposed to using an intermediary)?

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Older Canadians have a higher risk of medication-related patient safety incidents for a number of reasons, including

  • multiple co-morbidities
  • polypharmacy
  • age-related metabolic changes that can affect the absorption, distribution, metabolism, and elimination of a medication
  • cognitive impairment
  • decreased functional ability, including vision and hearing problems

High-alert medications

Analysis of the CMPA closed files identifies the following medications as being high risk for the elderly:

  • opioids
  • anti-depressant and anxiolytic medications
  • anti-thrombotics
  • cardiovascular drugs
  • cancer chemotherapeutic agents and steroids
  • non-steroidal anti-inflammatory drugs


Polypharmacy is a well-recognized phenomenon in the older population and can lead to poor medication adherence and unintended adverse reactions. Accordingly, identifying and de-prescribing potentially inappropriate medications for patients over the age of 65 is a growing area of focus for patient safety. Physicians can manage the complex medication needs of their older patients and promote medication safety through the use of de-prescribing guidelines and protocols.3, 4 Resources such as the STOPP/START criteria or the Beers Criteria can be used to guide prescribing to older patients and as supplements to clinical judgement.5 Physicians who review and re-evaluate medications should document their efforts and plans to discontinue medications safely. Pharmacists can play an important role by conducting regular medication reviews, working with older adults to reduce medication errors, recommending aids such as dosette boxes or blister packs, and assisting with de-prescribing.

Cognitive decline may exacerbate the complications of polypharmacy in older patients. Explaining a medication’s indication, monitoring requirements, adverse effects and special precautions to substitute decision-makers and family members involved in the patient’s care, with appropriate consent, can promote safe care. The informed consent and informed discharge discussions are key opportunities to promote medication safety.

When prescribing to patients over the age of 65, consider the following:

  • Do you perform an adequate patient evaluation before prescribing a medication?
  • Do you have a consent discussion with the patient or substitute decision-maker about the suggested medication?
  • Is your prescription legible?
  • Do you consider whether a dose modification is in order?
  • Are there contraindications to the drug you are prescribing?
  • Do you inform the patient or substitute decision-maker of potential side effects, and when and where to obtain additional care if indicated?
  • Do you arrange regular monitoring of drug levels or other measures of efficacy or toxicity?
  • Do you document your evaluation, consent discussion, and informed discharge advice in the medical record?

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According to ISMP Canada, opioids are the class of medications most frequently reported in adverse drug events resulting in harm.6

Managing the care of patients on high-dose or long-term opioid therapy for chronic non-cancer pain is complex. This problem calls for a strategic, patient-centered approach that incorporates guidelines, validated tools, provincial and territorial resources, as well as support from a multidisciplinary team. Clinical practice guidelines such as the Guideline for opioid therapy and chronic non-cancer pain support appropriate prescribing to reduce associated harms.7 Medical regulatory authorities (Colleges) also offer guidance and direction. The Opioid Manager from McMaster University may also be useful as a point of care tool.8

Factors around opioid prescribing that increase the risk of patient safety incidents include:

  • availability of multiple products and concentrations
  • different indicated dosages for the same product, depending on the route of administration
  • a range of presentations (tablets, liquids, patches)
  • a range of different timed-release preparations
  • look-alike and sound-alike names
  • look-alike packaging and labeling
  • mechanical problems with infusion and patient-controlled analgesia (PCA) pumps
  • varying patient monitoring requirements
  • pressure from patients to prescribe
  • challenges around side-effects of treatment with opioids and tapering of the doses

Patient safety concerns with opioid prescribing

CMPA data from cases of harm related to opioid prescribing highlight a number of themes to promote safe opioid prescribing:

  • the need for adequate assessment of patients when commencing opioids for chronic non-cancer pain, or when renewing or changing the dose of an opioid
  • the importance of validated assessment tools and treatment agreements
  • the importance of compliance assessments (for example using urine testing to document compliance with opioid therapy or to screen for other drugs of abuse)
  • the risks of concomitant prescription of other sedating medications such as benzodiazepines, or other psychotropic medications
  • the importance of monitoring of vital signs, respiratory status, pulse oximetry, and level of consciousness in patients at high risk of respiratory depression
  • the need for adequate consent discussion before initiating opioid therapy
  • the importance of thorough discharge instructions

The Institute for Safe Medication Practices of Canada (ISMP) provides helpful advice on risk management when prescribing an opioid.

Opioids-related challenges in physician-patient relationships

Accepting new patients

Many Colleges now explicitly state that it is not appropriate for physicians to decline to accept new patients solely on the basis of opioid use. When meeting with prospective patients who are on opioid therapy, physicians can foster understanding and a positive future relationship by reviewing the patient’s current treatment plan, and discussing the current chronic pain management guidelines and their own approach to treating chronic pain to help the patient decide whether the physician’s treatment philosophy will meet their needs.

Assuming care of patients on long-term opioid therapy

Physicians who assume the care of patients on long-term opioid therapy for chronic non-cancer pain often face challenges if they determine that they are facing a situation calling for an opioid taper. Revisiting the goals of opioid treatment; objectively assessing patients’ pain, function, and risk for opioid misuse; and establishing treatment contracts geared to supporting dose minimization are helpful approaches in long-term opioid therapy, and especially if dose tapering is indicated.

While a physician is never obliged to prescribe a medication, refusing to prescribe opioids to patients who have long-standing opioid use may lead to significant harm. Many Colleges deem it unacceptable to abruptly cease prescribing opioids. Because of potential withdrawal symptoms, patients may turn to the street to obtain replacement opioids. In such a situation, the risk of receiving street drugs contaminated with substances such as fentanyl and the inherent risk of overdose may outweigh that of measured continuation of physician-prescribed and monitored opioid therapy.

Involving a multidisciplinary team and relevant specialists when possible is also helpful for optimally managing the care of patients on long-term opioid therapy.

Dealing with opioid contract breaches

When faced with the difficult task of deciding how to manage opioid contract breaches, physicians should consider what a reasonably competent physician of similar training and in similar circumstances might do. Decisions should be made in a patient’s best interest in keeping with current standards. You can demonstrate your diligence in dealing with complex situations by:

  • documenting efforts to act in a reasonable manner in keeping with the patient’s best interests
  • documenting the rationale for prescribing
  • demonstrating attention to tolerance and tapering plans
  • using validated opioid management tools
  • following appropriate College guidelines when considering the possibility of having to terminate the doctor-patient relationship

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Checklist: Medication safety

Reducing the risk of drug-related harm

When prescribing medications, do you:

  • perform a medication reconciliation?
  • perform an adequate assessment of the patient?
  • review the patient’s allergies and possible medication contraindications?
  • determine the correct dosage and appropriate route of administration?
  • for a child, calculate doses based on the child's weight and write the weight on the prescription?
  • avoid prescribing in milliliters?
  • write legibly?
  • use a leading zero before a decimal point for doses that are less than one (e.g. 0.2 mg)?
  • avoid using a trailing zero by itself after a decimal point (e.g. 5 mg)?
  • request a repeat-back if the medication was ordered over the telephone?
  • obtain and document informed consent?
  • provide and document discharge instructions?
  • convey, with appropriate consent, any medication changes to those caring for the patient (e.g. family)?
  • relay any medication changes to the primary care physician?

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When prescribing off-label medications and devices, do you:

  • consider the reasonableness of off-label use?
  • determine if the patient has a condition that would place them at increased risk of potential side effects?
  • obtain and document informed consent?
  • document the rationale for using the medication?
  • plan for careful monitoring of patients for side effects?

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When prescribing opioids, do you:

  • perform an adequate assessment?
  • establish a clear rationale for starting an opioid?
  • consider current prescribing criteria?
  • consider the patient’s risk factors for problem usage?
  • recommend the lowest possible dose of the weakest possible opioid for the shortest possible time?
  • develop a well-defined treatment plan and treatment agreement?
  • consider guidelines for stopping or tapering opioids appropriately?
  • obtain and document informed consent?
  • plan for careful monitoring of the patient?
  • consider whether an opioid contract is appropriate?
  • consider involving a multidisciplinary team, as necessary?

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  1. Laubscher T, Evans C, Blackburn D, et al. Collaboration between family physicians and community pharmacists to enhance adherence to chronic medications: opinions of Saskatchewan family physicians. Can Fam Physician. 2009;55(12):e69-e75. Available from: https://pubmed.ncbi.nlm.nih.gov/20008581/
  2. Institute for Safe Medication Practices Canada, Safety Bulletin/National Collaborative. Top 5 Drugs Reported as Causing Harm through Medication Error in Paediatrics. Aug 2009;9(6). Available from: http://www.ismp-canada.org/download/safetyBulletins/ISMPCSB2009-6-NationalCollaborative-Top5DrugsReported.pdf
  3. Sirois C, Ouellet N, Reeve E. Community-dwelling older people’s attitudes towards deprescribing in Canada. Res Soc Admin Pharm. 2017;13(4):864-870. Available from: https://pubmed.ncbi.nlm.nih.gov/27663392/
  4. Canadian Deprescribing Network. Deprescribing algorithm. 2017. Available from: https://www.deprescribingnetwork.ca/algorithms
  5. American Geriatrics Society. 2015 Beers Criteria Update Expert Panel. American Geriatrics Society 2015 Updated Beers Criteria for Potentially Inappropriate Medication Use in Older Adults. J Am Geriatr Soc. 2015 Nov ;63(11):2227-46. Available from: https://pubmed.ncbi.nlm.nih.gov/26446832/
  6. Colquhoun, M, Koczmara, C, Greenall, J. Implementing system safeguards to prevent error-induced injury with opioids (narcotics): An ISMP Canada Collaborative. Healthc Q. 2006 Oct 9 special issue:36.
  7. Busse JW, Craigie S, Juurlink DN, et al. Guideline for opioid therapy and chronic noncancer pain. CMAJ. 2017 May 8;189(18):E659-E666
  8. Opioid Manager [Internet]. McMaster University; Michael G. DeGroote National Pain Centre. 2011 Feb. Available at: https://fhs.mcmaster.ca/npc/opioidmanager/
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DISCLAIMER: The information contained in this learning material is for general educational purposes only and is not intended to provide specific professional medical or legal advice, nor to constitute a "standard of care" for Canadian healthcare professionals. The use of CMPA learning resources is subject to the foregoing as well as the CMPA's Terms of Use.