Nitrosamine Impurities in 2026: Health Canada's Updated Guidance, New AI Limits and What MAHs Must Do Now

On May 29, 2026, Health Canada posted a revised version of its Guidance on Nitrosamine Impurities in Medications. The headline change is procedural, but it matters to every drug company operating in Canada. Market Authorization Holders (MAHs) no longer have to notify Health Canada each time an elevated nitrosamine level is detected. Notification is now required only when a recall decision has been made. This change arrives soon after a separate update, posted March 11, 2026, that revised the list of established Acceptable Intake (AI) limits by adding one new nitrosamine and tightening the limits for seven others. Read together, the two updates reset the compliance baseline for anyone holding a Canadian drug authorization.

Executive summary

Nitrosamines are probable human carcinogens that can form as trace impurities in drug substances and finished products. Since the valsartan recalls of 2018, Health Canada has required companies to assess, test for, and control these impurities across their portfolios. The 2026 updates do not relax that expectation. They refine how and when companies talk to the regulator, and they move several Acceptable Intake limits, the numerical ceilings that decide whether a batch is safe to keep on the market.

For MAHs, the practical message is simple. Re-baseline every nitrosamine risk assessment against the current Appendix 1, confirm that analytical methods can measure to the revised limits, and rewrite the notification and recall triggers in your quality management system so they match the new guidance. Companies that treat the 2026 changes as a routine document refresh risk either over-reporting to Health Canada or, far worse, missing a recall obligation.

What changed on May 29, 2026?

In short, the reporting trigger moved. Under the previous guidance, an MAH had to inform Health Canada whenever confirmatory testing found a nitrosamine above its AI limit. Under the revised guidance, that step-by-step notification is gone. After confirmatory testing, the MAH assesses whether the impurity exceeds the AI limit and decides whether market action is needed. Health Canada is notified only if the company decides to initiate a recall, and that report follows the process in the Drug, Natural Health Product and Biocide Recall Guide (GUI-0039).

Three other refinements travelled with the May 2026 update:

• Risk mitigation expectations. The guidance keeps the three-year corrective and preventive action (CAPA) timeline, but Health Canada restates that MAHs should reduce nitrosamine levels below the AI limits as soon as possible, not at the end of the runway.
• Safety enquiries. Health Canada added new contact information for questions about applicable AI limits, including how to propose a new AI limit for a nitrosamine that is not yet listed.
• Appendix 2 decision tree. The decision tree for filing nitrosamine risk-mitigation changes was updated to match the revised reporting expectations.

The March 11, 2026 update to Acceptable Intake limits

An Acceptable Intake limit is the maximum daily amount of a specific nitrosamine, expressed in nanograms per day (ng/day), that a person can be exposed to over a lifetime with negligible cancer risk. Health Canada publishes these limits in Appendix 1 of the guidance, now maintained as a standalone web page and downloadable Excel file. The version dated March 11, 2026 made two kinds of change.

• One new entry. Health Canada added N-nitroso-dabigatran etexilate imide, a nitrosamine drug substance-related impurity (NDSRI) connected to the anticoagulant dabigatran etexilate, with its own AI limit.
• Seven revised limits. Health Canada changed the AI limits for seven nitrosamines already on the list. The most consequential is N-nitroso-meglumine, whose limit fell from 1,500 ng/day to 100 ng/day, a fifteen-fold tightening. Other revised entries include nitrosamines related to folic acid, diltiazem, vancomycin, labetalol and paroxetine.

What are nitrosamines and NDSRIs?

Nitrosamines are a family of compounds that share an N-nitroso group. Many are potent, DNA-reactive (mutagenic) carcinogens in animal studies, which is why regulators treat even trace amounts seriously. In medicines, they can form when a secondary or tertiary amine meets a nitrosating agent during synthesis or storage, and they can also be introduced through certain excipients, water, or packaging.

NDSRIs, or nitrosamine drug substance-related impurities, are a sub-class that became a regulatory focus more recently. Instead of being small, generic molecules like NDMA, an NDSRI is structurally related to the active ingredient itself. Because each NDSRI is essentially unique to its drug, companies often cannot rely on read-across data and must establish a limit from first principles. The dabigatran-related impurity added in March 2026 is a textbook NDSRI.

The issue is not academic. The global nitrosamine story began in 2018, when NDMA and NDEA were found in valsartan and other sartan blood-pressure medicines, triggering worldwide recalls. Health Canada's October 2, 2019 call for review grew out of those events and was extended to biological and radiopharmaceutical products in December 2020.

How Health Canada sets Acceptable Intake limits

Health Canada uses three routes to set an AI limit, in order of preference. First, compound-specific carcinogenicity data, extrapolated to a one-in-100,000 lifetime cancer risk. Second, a structure-activity read-across to a closely related surrogate that has robust data. Third, when neither is available, the Carcinogenic Potency Categorization Approach (CPCA).

The CPCA assigns a nitrosamine to one of five potency categories based on its chemical structure, specifically the alpha-hydrogen atoms next to the N-nitroso group and any activating or deactivating features. Each category carries a default AI limit between 18 and 1,500 ng/day. A negative result from an enhanced Ames test, run under the conditions in Appendix 3 of the guidance, can support a higher limit of 1,500 ng/day (1.5 micrograms/day), the threshold of toxicological concern in ICH M7.

The three-step framework and the 2028 CAPA deadline

Health Canada's nitrosamine program runs on three steps. Step 1 is a risk assessment to identify whether any nitrosamine could form or be introduced. Step 2 is confirmatory testing with validated, sensitive analytical methods. Step 3 is changes to the market authorization to lock in the control strategy. The original filing deadlines have passed, with Step 3 changes due by August 1, 2025.

What remains live is the CAPA implementation timeline. For nitrosamines whose AI limit was published before August 1, 2025, MAHs may take up to three years from that date, so until August 1, 2028, to fully implement the necessary changes. For limits published on or after August 1, 2025, the three-year clock starts on the publication date of that limit. The revised 2026 guidance underlines that these timelines are a backstop, not a target. Companies are expected to drive levels below the AI limits as quickly as they reasonably can.

Which products are in scope?

The nitrosamine requirements apply broadly across human drugs, but not to everything Health Canada regulates. Knowing exactly where your products sit avoids both wasted effort and dangerous gaps.

• In scope: prescription and non-prescription (over-the-counter) drugs with a drug identification number (DIN) that contain chemically synthesized or semi-synthetic active ingredients, along with the excipients and raw materials used to make them.
• In scope: all biological and radiopharmaceutical products for human use, including vaccines, plasma proteins and cell-based fermentation products.
• Out of scope (at this time): cosmetics without a DIN, natural health products, veterinary products, standalone antimicrobial agents and hard-surface disinfectants.

What MAHs must do now

The 2026 updates translate into a focused set of actions. None of them are exotic, but each one needs a documented owner and a date.

1. Re-baseline every risk assessment. Compare each product's nitrosamine profile against the current Appendix 1. Flag any impurity whose limit changed, especially N-nitroso-meglumine, and any NDSRI now listed.
2. Re-check analytical methods. Confirm your methods are validated to detect and quantify each relevant nitrosamine at or below the revised limit. A limit that drops to 100 ng/day may demand a more sensitive method.
3. Update stability and specification limits. Where an AI limit moved, revisit shelf-life justifications and product specifications that reference the old ceiling.
4. Rewrite the notification and recall triggers. Edit your QMS and recall SOPs so that Health Canada is notified on a recall decision per GUI-0039, not on every elevated result.
5. Map your CAPA deadlines. Record the publication date of each applicable AI limit and the resulting implementation date, with August 1, 2028 as the anchor for limits published before August 2025.
6. Document everything. If an inspector asks, you should be able to show the assessment, the method, the decision, and the rationale for whether or not you reported.

Nitrosamine compliance checklist

• Current Appendix 1 (March 11, 2026 version) downloaded and circulated to QA and regulatory affairs
• Every product re-screened against the revised AI limits, with meglumine-containing formulations prioritized
• Analytical methods validated to the lowest applicable AI limit
• Cumulative limits applied where products contain more than one nitrosamine
• Stability data and specifications reconciled with the revised limits
• QMS notification trigger updated to a recall-decision basis (GUI-0039)
• Recall SOP cross-referenced to the Drug, Natural Health Product and Biocide Recall Guide
• CAPA implementation dates logged against each AI limit publication date
• Drug establishment licence terms and conditions reviewed for nitrosamine testing obligations
• Roles, decisions and rationales documented for inspection readiness

Common mistakes to avoid

• Treating the update as housekeeping. The notification change alters a regulatory obligation. It belongs in your QMS, not just your reading pile.
• Forgetting excipients. Nitrosamine risk does not stop at the active ingredient. Meglumine is the reminder that a buffer or excipient can move you out of compliance.
• Single-impurity tunnel vision. Ignoring cumulative limits when two or more nitrosamines are present is a frequent inspection finding.
• Stale analytical methods. A method that was fit for a 1,500 ng/day limit may be blind to a 100 ng/day limit.
• Over-reporting. Notifying Health Canada at every elevated detection is no longer expected and can muddy the record. Match your reporting to the new trigger.
• Under-reporting. The flip side is worse: failing to report a recall decision through the proper GUI-0039 process.

Frequently asked questions

Do MAHs still need to test for nitrosamines?

Yes. The 2026 update changes when you notify Health Canada, not whether you test. Confirmatory testing against the Acceptable Intake limit remains a core expectation, and your analytical methods must be sensitive enough to measure to the revised limits.

When do we now have to notify Health Canada?

Only when you have made a decision to recall a product. At that point you report through the Drug, Natural Health Product and Biocide Recall Guide (GUI-0039). You no longer file a separate notification for each elevated nitrosamine result.

What is the new N-nitroso-meglumine limit?

Health Canada reduced the Acceptable Intake limit for N-nitroso-meglumine from 1,500 ng/day to 100 ng/day in the March 11, 2026 version of Appendix 1. Because meglumine is widely used as an excipient, this change can affect products that previously complied.

What is an NDSRI?

An NDSRI is a nitrosamine drug substance-related impurity, a nitrosamine whose structure is derived from the active ingredient itself. NDSRIs usually need a compound-specific limit, often set using the Carcinogenic Potency Categorization Approach. The dabigatran-related impurity added in March 2026 is an example.

Does the three-year CAPA timeline still apply?

Yes, but with emphasis. Companies may take up to three years from an AI limit's publication date to implement changes, with August 1, 2028 anchoring limits published before August 1, 2025. Health Canada expects levels to be reduced below the limits as soon as possible within that window.

Are natural health products and cosmetics covered?

Not at this time. The requirements apply to human drugs with a DIN, including biologics and radiopharmaceuticals. Natural health products, cosmetics without a DIN, veterinary products and hard-surface disinfectants are currently outside the scope, though good quality practice still applies.

How MFLRC can help

Re-baselining a nitrosamine program against shifting limits is detailed, document-heavy work, and it sits at the intersection of regulatory affairs, quality assurance and analytical science. MFLRC supports pharmaceutical and biologic MAHs across the full nitrosamine lifecycle.

• Risk assessment review: a fresh gap analysis of your nitrosamine risk assessments against the March 11, 2026 Appendix 1, with priority flags for changed limits and newly listed NDSRIs.
• Analytical method validation coordination: working with your labs to confirm methods are validated and sensitive enough for the revised AI limits.
• Stability and specification updates: aligning shelf-life justifications and product specifications with the current limits.
• QMS and recall SOP revision: rewriting your notification and recall triggers to the new GUI-0039 basis so your procedures match the guidance.
• Regulatory submission support: preparing and filing the control-strategy and market-authorization changes that flow from a revised assessment.

Whether you hold a single DIN or a broad portfolio, our senior consultants translate Health Canada's expectations into practical, inspection-ready deliverables. To discuss your portfolio, contact our team.

Conclusion

The 2026 changes to Health Canada's nitrosamine guidance are easy to underestimate. The notification update sounds like a simplification, and in workflow terms it is. But it shifts responsibility onto your internal assessment and your recall decision-making, and it lands alongside revised Acceptable Intake limits that can quietly push compliant products out of bounds. The companies that come through cleanly will be the ones that re-baseline now, document their reasoning, and treat the AI limit list as a living specification rather than a static reference.

Sources and references

• Health Canada. Guidance on Nitrosamine Impurities in Medications.
• Health Canada. Nitrosamine impurities in medications: Established acceptable intake limits (Appendix 1).
• Health Canada. Nitrosamine impurities in medications: Overview.
• Health Canada. Drug, Natural Health Product and Biocide Recall Guide (GUI-0039).
• ICH. M7(R2): Assessment and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals to Limit Potential Carcinogenic Risk.

This article is for general information and does not constitute regulatory or legal advice. Always refer to the current Health Canada guidance for your specific products.