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PEBC Medication Safety and Distribution Practice Questions

Do Not Use abbreviations, storage, cold chain, compounding and inventory: ten distribution and safety questions for the PEBC MCQ.

Updated November 13, 2026. Written by RxReady to the 2026 PEBC blueprint. These are practice questions, not real or recalled exam questions.

Drug distribution and medication safety make up a real share of the PEBC blueprint, and they are often under-studied. These questions are about how a pharmacy runs safely: storing products correctly, catching dangerous abbreviations, compounding and managing stock.

This set covers returned medications, ISMP Canada Do Not Use abbreviations, epinephrine auto-injector and biologic storage, drug stability, sterile compounding, cold chain breaks and stock rotation.

Many of these answers come down to one principle: when the quality or safety of a product cannot be confirmed, it does not go to the patient.

Practice by topic

Ten medication safety questions

Question 1 · Return of medications to inventory

Which of the following medications may be returned to the pharmacy's dispensing inventory?

  1. AAn unopened bottle returned by a patient the day after pick-up because the dose was changed
  2. BA never-picked-up fill in the unopened manufacturer's container that never left the pharmacy
  3. CSealed blister cards returned unused from a long-term care facility
  4. DAn unopened box of insulin pens returned by a caregiver after the patient was hospitalized last week
Show the answer

Answer: B) A never-picked-up fill in the unopened manufacturer's container that never left the pharmacy

A medication that never left the pharmacy's control (e.g., an unclaimed prescription still in the unopened original manufacturer's container) can be returned to stock after reversing the claim, because its storage and integrity are known. Once medications have left the pharmacy, storage conditions (temperature, tampering) cannot be verified, so they must not be returned to inventory and are instead accepted for destruction. This is especially important for cold-chain products such as insulin.

Why the other options are wrong

  • A) Once a bottle has left the pharmacy, its storage cannot be verified, so it cannot be restocked.
  • C) Medications returned from a facility have left pharmacy control and must not be restocked.
  • D) Returned insulin's cold chain cannot be verified, so it must not be restocked.

Key point: Only medications that never left the pharmacy's control may go back into stock.

Question 2 · Medication safety

Which of the following appears on ISMP Canada's Do Not Use list of dangerous abbreviations?

  1. A"mg" to mean milligram
  2. B"mL" to mean millilitre
  3. C"mcg" to mean microgram
  4. D"OD" to mean once daily
Show the answer

Answer: D) "OD" to mean once daily

ISMP Canada lists "OD" for once daily as a dangerous abbreviation because it can be mistaken for "right eye" (oculus dexter), leading to oral medications being instilled in the eye or vice versa; "daily" should be written out. "mcg" is the recommended replacement for "µg", and "mg" and "mL" are acceptable.

Why the other options are wrong

  • A) 'mg' is an accepted abbreviation.
  • B) 'mL' is an accepted abbreviation.
  • C) 'mcg' is the recommended replacement for 'µg'.

Key point: Do Not Use: OD, U, IU, QD, trailing zeros, MS/MSO4, µg.

Question 3 · Storage

Which of the following is the most appropriate storage advice for an epinephrine auto-injector?

  1. ARefrigerate it at 2 to 8 °C to extend its shelf life
  2. BKeep it in the car's glove compartment year-round so it is always available
  3. CRemove it from its carrier tube so it is easier to grab
  4. DKeep it at room temperature and replace it if the solution is discoloured
Show the answer

Answer: D) Keep it at room temperature and replace it if the solution is discoloured

Epinephrine auto-injectors are stored at room temperature (15 to 30 °C), not refrigerated or frozen, and kept in their carrier tube to protect them from light. Patients should check the viewing window and replace the device if the solution is discoloured or contains a precipitate, or when it expires. Vehicles expose the device to temperature extremes that degrade epinephrine.

Why the other options are wrong

  • A) Auto-injectors should not be refrigerated or frozen; store at room temperature (15 to 30 °C).
  • B) A car exposes the device to heat and cold that degrade epinephrine.
  • C) The carrier tube protects the device from light and damage, so it should stay in it.

Key point: Epinephrine auto-injector: room temperature, in its tube, check the window, replace if discoloured.

Question 4 · Medication safety

Which of the following opioid orders is written in accordance with ISMP Canada's recommendations?

  1. AMSO4 10 mg PO q4h PRN
  2. BMS 10 mg PO q4h PRN
  3. CMorphine 10 mg PO q4h PRN
  4. DMorphine 10.0 mg PO q4h PRN
Show the answer

Answer: C) Morphine 10 mg PO q4h PRN

ISMP Canada's Do Not Use list includes MS and MSO4, which can mean morphine sulfate or magnesium sulfate, and trailing zeros (10.0 mg), which can be misread as 100 mg. Drug names should be written out in full, with no trailing zeros.

Why the other options are wrong

  • A) MSO4 can be confused with magnesium sulfate.
  • B) MS can mean morphine sulfate or magnesium sulfate.
  • D) The trailing zero (10.0) can be misread as 100 mg.

Key point: Write drug names in full (not MS or MSO4) and never use trailing zeros.

Question 5 · Drug stability

A patient returns a bottle of ASA tablets that smell strongly of vinegar. This odour results from

  1. Ahydrolysis to salicylic and acetic acids
  2. Boxidation forming quinone derivatives
  3. Cphotolysis forming free radicals
  4. Dracemization of the active ingredient
Show the answer

Answer: A) hydrolysis to salicylic and acetic acids

ASA (acetylsalicylic acid) is an ester that hydrolyzes in the presence of moisture to salicylic acid and acetic acid; acetic acid causes the vinegar odour. The tablets should be discarded and stored away from humidity. Oxidation, photolysis and racemization are not the main degradation pathway for ASA.

Why the other options are wrong

  • B) Oxidation isn't ASA's main degradation pathway.
  • C) Photolysis isn't the cause of the vinegar odour.
  • D) Racemization doesn't apply; ASA isn't chiral.

Key point: Vinegar-smelling ASA = hydrolysis. Discard and store dry.

Question 6 · Drug stability and storage

Which of the following is the most appropriate storage advice for nitroglycerin sublingual tablets?

  1. AKeep tightly closed in the original glass bottle
  2. BTransfer them to a plastic weekly pill organizer
  3. CRefrigerate them in a dosette box
  4. DRemove the cap to allow ventilation
Show the answer

Answer: A) Keep tightly closed in the original glass bottle

Nitroglycerin is volatile and can migrate into plastic and evaporate, so SL tablets are supplied in glass bottles that must be tightly closed after each use and kept away from heat and moisture. Transferring them to plastic organizers or leaving the cap off causes loss of potency.

Why the other options are wrong

  • B) Nitroglycerin migrates into plastic and loses potency.
  • C) A dosette box is plastic and exposes tablets to moisture.
  • D) Leaving the cap off lets nitroglycerin evaporate.

Key point: SL nitroglycerin: original glass bottle, tightly capped.

Question 7 · Biologic storage

Which of the following is the most appropriate storage advice for unopened etanercept prefilled pens?

  1. AStore in the freezer; thaw before use
  2. BStore at room temperature away from light
  3. CRefrigerate at 2 to 8°C; freezing is acceptable
  4. DRefrigerate at 2 to 8°C; do not freeze or shake
Show the answer

Answer: D) Refrigerate at 2 to 8°C; do not freeze or shake

Protein biologics such as etanercept should be refrigerated at 2-8°C in the original carton to protect from light. Freezing and vigorous shaking can denature or aggregate the protein, reducing efficacy and increasing immunogenicity. Some products may be kept at room temperature for a limited, labelled period.

Why the other options are wrong

  • A) Freezing denatures the protein.
  • B) Unopened pens need refrigeration.
  • C) Freezing isn't acceptable for biologics.

Key point: Biologics: refrigerate, protect from light, don't freeze or shake.

Question 8 · Compounding

A pharmacy receives four compounding requests. Which preparation must be prepared as a sterile product?

  1. AVancomycin oral solution for C. difficile infection
  2. BHydrocortisone rectal suppositories
  3. CFortified tobramycin eye drops
  4. DKetoconazole 2% topical cream
Show the answer

Answer: C) Fortified tobramycin eye drops

Ophthalmic preparations, like parenterals, must be sterile because contamination can cause serious eye infections (e.g., Pseudomonas keratitis) and vision loss. Compounded sterile preparations must follow NAPRA's sterile compounding standards. Oral, rectal and topical preparations must meet microbial limits but are not required to be sterile, even when the oral product is for a serious infection.

Why the other options are wrong

  • A) Oral solutions need microbial limits but not sterility, even for C. difficile treatment.
  • B) Rectal preparations are non-sterile products.
  • D) Topical creams are non-sterile preparations.

Key point: Must be sterile: parenterals and ophthalmics (and irrigations). Oral, rectal and topical: no.

Question 9 · Cold chain

Which of the following products must be stored in a refrigerator (2–8 °C) in the pharmacy before dispensing?

  1. ANitroglycerin sublingual tablets
  2. BSalbutamol metered-dose inhaler
  3. CUnopened insulin glargine pens
  4. DLevothyroxine tablets
Show the answer

Answer: C) Unopened insulin glargine pens

Unopened insulin is refrigerated until use. Once in use, pens can be kept at room temperature for the period on the label. Why not the others: A: Room temperature in the original glass container, tightly closed; not refrigerated. B: Stored at room temperature; avoid extremes. D: Stored at room temperature, protected from light and moisture. Key takeaway: Unopened insulin → fridge; in-use pens → room temperature for the labelled number of days.

Why the other options are wrong

  • A) Sublingual nitroglycerin tablets are kept at room temperature in the original tightly closed glass bottle.
  • B) Salbutamol inhalers are stored at room temperature, away from temperature extremes.
  • D) Levothyroxine is stored at room temperature, protected from light and moisture.

Key point: Unopened insulin goes in the fridge; in-use pens stay at room temperature for the labelled days.

Question 10 · Inventory

When receiving and shelving stock, which of the following practices best minimizes losses from expired products?

  1. APlace new stock in front of older stock so that it is easier to access
  2. BOrder the maximum quantity allowed to obtain volume discounts
  3. CRotate stock so products with the earliest expiry are used first
  4. DCheck expiry dates only at the annual physical inventory
Show the answer

Answer: C) Rotate stock so products with the earliest expiry are used first

First-expiry, first-out rotation places the earliest-dating stock in front so it is used before it expires, reducing waste and the risk of dispensing expired product. Placing new stock in front leaves older stock to expire, over-ordering increases carrying costs and expiry risk, and expiry checks should be performed regularly (e.g., monthly), not just annually.

Why the other options are wrong

  • A) Placing new stock in front leaves older stock at the back to expire.
  • B) Over-ordering raises carrying costs and the risk of products expiring.
  • D) Checking expiry only once a year is too infrequent; check regularly (e.g., monthly).

Key point: Rotate stock: first-expiry, first-out.

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