Can I Use a Different Strength During a Medication Shortage in Canada?

1When a strength switch is sometimes possible

For plain immediate-release tablets, it's sometimes possible to reach your usual dose using a different strength that's in stock — for example, two 5 mg tablets in place of one 10 mg tablet. Whether that's appropriate depends on the specific drug and your dose, which is exactly why it needs to go through your pharmacist rather than being worked out at home.

2When it's not safe

Extended-release and controlled-release formulations are designed to release the drug slowly over time — splitting or combining them can release the full dose at once, which can be unsafe. The same caution applies to enteric-coated tablets and drugs with a narrow therapeutic range, where small dosing errors matter more than usual. Your pharmacist will know whether your specific medication falls into one of these categories.

3Why self-adjusting is risky

Beyond the release-mechanism issue, manually splitting or combining doses introduces room for error — tablets don't always split evenly, and the math for converting between strengths isn't always as simple as it looks, especially for drugs where the difference between too little and too much matters.

4What your pharmacist will consider

A pharmacist weighing a strength substitution looks at more than just the number on the label — your other medications, existing conditions, and how precisely your dose needs to be controlled all factor in. That's the judgment call they're trained to make, and it's specific to you, not a general rule that applies to everyone on the same drug.

5Bottom line

Never change your strength or split doses on your own because of a shortage. Ask your pharmacist first — see Can a Pharmacist Substitute a Medication During a Shortage? for what they can typically do and when your prescriber needs to be involved.