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Medication risks

Safe care and medications

Medications for children

Group of smiling childrenChildren are at increased risk for adverse drug events for many reasons:
  • Substantial differences in body surface area, weight, and organ maturity (e.g. between neonates, toddlers, adolescents).
  • The need for individualized dosage calculations based on weight or body surface area, age, and clinical condition.
  • Immature physiological systems in younger children that affect medication absorption, metabolism, and excretion.
  • Limited dosing range.
  • Lack of information on indications and dosing (due, in part, to a lack of clinical trials in children).
  • Inability of children to communicate the adverse effects of a medication.
  • Varying degrees of experience among healthcare professionals caring for paediatric patients.

The Institute for Safe Medication Practices Canada (ISMP Canada) has identified the top five medications that frequently result in serious adverse drug events in paediatric patients:  [REF]

Institute for Safe Medication Practices Canada, Safety Bulletin/National Collaborative, "Top 5 Drugs Reported as Causing Harm through Medication Error in Paediatrics." Available from: http://www.ismp-canada.org/download/safetyBulletins/ISMPCSB2009-6-NationalCollaborative-Top5DrugsReported.pdf
  1. morphine
  2. potassium chloride
  3. insulin
  4. fentanyl
  5. salbutamol

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

Case: No leading zero or decimal point for a medication
Small child receiving medicine


A resident diagnoses gastroesophageal reflux following her assessment of a six-month-old infant.

Based on the weight and length of the baby, the resident determines the correct dose of Maxeran® (metoclopramide) is 0.2 mg PO QID before feeds. However, she fails to write a leading zero and a decimal point before the number "2" on the prescription.


The pharmacist dispenses the "2 mg" dose as per the prescription. After receiving six doses of 2 mg, the infant develops a dystonic reaction, which requires hospitalization.

Think about it

  • How could the resident have prevented this prescription error?


  • The resident should have carefully double-checked the prescription before giving it to the parent. Had he performed this simple safety check, he probably would have realized the decimal point was missing from the intended dose.
  • Regular use of a leading zero may have prompted him to notice the decimal point was missing on the prescription.

Lessons learned

  • Writing medication orders and prescriptions requires your full attention.
  • Every medication order and prescription should be legible.
  • When the intended dose has a decimal point, be especially careful to insert the decimal point clearly.
  • Use a leading zero before a decimal point for doses that are less than one, (e.g. 0.2 mg).
  • Never use a trailing zero by itself after a decimal point (e.g. 5 mg).
  • Carefully double-check that the prescription contains all of the required elements before giving it to the parent or adolescent.

Case: Omission of critical information on a prescription
Woman on cell phone holding infant


Following a thorough clinical assessment of a two-month-old infant, a family physician diagnoses a non-resolving upper respiratory tract infection. He intends to prescribe amoxicillin 125 mg/5 ml strength solution, 2.5 ml, which would equate to 62.5 mg, three times per day for five days.

However, he actually prescribes 125/5 ml three times per day, which is twice the recommended dosage for the infant's weight.

After the mother leaves the office, the doctor realizes his error in dosage and notifies the mother.

The mother subsequently complains to the medical regulatory authority (College).


The College recommended that the physician weigh infants and children before prescribing medications to avoid medication errors in the future.

Think about it

  • Why is the weight of an infant or child so important when prescribing medications?
  • How could this prescription error have been prevented?


  • Weight-based dosing is an integral part of paediatric care. To calculate the correct medication dose, the baby's current weight is required. This is especially important with younger children due to immaturity of their organs.
  • The physician should have calculated the dose of amoxicillin based on the baby's weight and age.
  • The physician should have carefully double-checked the prescription before giving it to the mother rather than waiting until the mother and baby left the office.

Lessons learned

  • Obtain the child's weight prior to prescribing any medication.
  • Determine the appropriate dose of the medication based on the child's weight, age, and clinical condition.
  • Use mg/kg or mg/m2 as the basis for your dose calculations.
  • Double-check that all of the required elements are included on the prescription before giving it to the parent or adolescent.

Safety measures based on the CMPA experience

Experts in the closed medical-legal cases believe certain adverse events (accidents in Québec) related to medications might be prevented if the physician:
  • researches unfamiliar medications
  • bases the medication dosage on the patient's current weight
  • uses legible handwriting on the prescription
  • double-checks the calculation of a medication dosage
  • when indicated, tapers the dosage before discontinuing the medication
  • labels medications clearly
  • documents the administration of a medication
  • provides clear instructions to the patient when an existing prescription is modified
  • monitors the efficacy of a medication, identifies potential adverse effects, or reevaluates the child's condition before renewing a medication

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Risk management suggestions

The following considerations to manage risk are based on the expert opinions in a review of the CMPA's medical-legal case files:
  • Have you calculated individual doses based on the child's weight or body surface area and clinical condition?
  • Are medication reference materials or treatment algorithms readily available and is the information current and clear?
  • Are consultant recommendations clear, particularly when divided medication doses are indicated?
  • Have you verified the medication, dose calculation, solution concentration, and route of administration?
  • Have you considered the concerns of other healthcare professionals about a medication dose?
  • Are your prescriptions legible?
  • If a change is required to an existing medication order, whether handwritten or by computer order entry, have you made the correction according to established documentation principles?
  • Have you monitored the efficacy of a medication, identified potential adverse effects, or re-evaluated the child's condition before renewing a prescription?
  • Are your medical records accurate, up to date, and written at the time of the patient encounter (contemporaneous)?