What Is the New Approved Treatment for Hot Flashes and Night Sweats?

A woman resting on a sofa, pressing a folded cloth to her forehead to cool down

Health Canada has expanded its authorization of elinzanetant, sold as Lynkuet, to cover women experiencing moderate to severe hot flashes and night sweats from the endocrine therapy that keeps their breast cancer from returning. It is non-hormonal, which is the entire point, because hormone replacement is not an option for this group. Bayer says it is not publicly funded in Canada yet and has not released a price.

Key takeaways

Elinzanetant was first approved in July 2025 for symptoms in women going through menopause. The new authorization extends that to breast cancer patients.

About two-thirds of breast cancers are hormone-receptor positive, meaning they need estrogen to grow.

Patients typically stay on anti-estrogen medication for roughly five to ten years.

The OASIS-4 trial followed 395 women aged 18 to 70 over 52 weeks, all having at least 35 moderate to severe episodes a week at enrolment.

The most common side effects were daytime drowsiness, fatigue and diarrhea.

At the end of the trial, 91.6 percent of participants chose to keep taking it for another two years.

For years, women on treatment to stop their breast cancer returning have faced a cruel trade-off. The medication doing the protecting is also what sets off the hot flashes and night sweats, and the usual remedy is the one thing they cannot have.

Why is hormone therapy not an option for these patients?

Because the treatment works by removing estrogen. About two-thirds of breast cancers are hormone-receptor positive, meaning they need estrogen to grow, so oncologists block the body's production of it, usually with tamoxifen or an aromatase inhibitor taken for roughly five to ten years. Chemotherapy adds to it by stopping the ovaries from working and pushing patients into menopause. Putting estrogen back is therefore not on offer, which is why hormone therapy not being an option is the starting point here; in a way, it is not for other women.

These are not minor irritations. A moderate episode means heat and sweating. A severe one is intense enough to make a woman stop whatever she is doing. Dr. Christine Brezden-Masley, medical director of the cancer program at Sinai Health in Toronto, who receives compensation as a consultant to Bayer, says symptoms can get debilitating enough that some patients stop taking their cancer medication to make them stop. That is exactly what oncologists work to prevent, because staying on endocrine therapy is what keeps the cancer from coming back.

Until now, the workaround has been improvisation, prescribing older drugs off-label, including the anticonvulsant gabapentin and the antidepressant Effexor, which help some patients a little and others barely at all. Joint stiffness and aching from aromatase inhibitors is another under-discussed part of the same picture, and our explainer on why joints hurt more than they used to covers what else can be behind it.

How does the new non-hormonal treatment for hot flashes work?

It targets the brain rather than the hormones. Understanding the non-hormonal treatment for hot flashes starts with what happens when estrogen drops. A cluster of neurons involved in temperature regulation, known as KNDy neurons, can become hyperactive without estrogen, and that hyperactivity is what triggers the flush and the sweat.

Elinzanetant belongs to a class called neurokinin receptor antagonists, which act directly on those neurons. Bayer describes it as the first medication blocking both the NK-1 and NK-3 receptors to be authorized for these symptoms. Because it never touches estrogen, it is suitable for women who cannot go near hormone therapy.

What did the trial on endocrine therapy find?

The approval rests on Bayer's OASIS-4 study, a Phase 3 randomized placebo-controlled trial that Brezden-Masley describes as the first to look specifically at breast cancer patients on anti-estrogen therapy. The trial on endocrine therapy found a significant drop in daily episodes compared with placebo, along with fewer sleep disturbances.

It followed 395 women aged 18 to 70 receiving endocrine therapy, over 52 weeks. To qualify, participants had to be having at least 35 moderate to severe episodes a week when they enrolled. The most common side effects were daytime drowsiness, fatigue and diarrhea. The number that says most about how patients experienced it is the one at the end, where 91.6 percent chose to continue taking it for a further two years.

Dr. Dave Cescon, a medical oncologist and clinician scientist at Princess Margaret Cancer Centre in Toronto who has no financial ties to Bayer, says menopausal symptoms are a major issue for many patients that historically have not been well addressed, and expects the approval to be genuinely helpful.

What should you do to talk to your care team about symptom relief?

Symptoms only get managed if they get reported, and they are chronically under-reported. To talk to your care team about symptom relief productively, take these four steps.

Count the episodes for a week. Note how many happen in the day and how many wake you at night. Frequency is what treatment decisions are built on, and it is much more useful than saying they are bad.

Say plainly what they are costing you. Interrupted meetings, lost sleep, avoided activities. Clinicians act on function, not just on symptom counts.

Bring what you have already tried, including doses and why you stopped. Being groggy on gabapentin is a clinically meaningful reason, not a complaint.

Say it out loud if you have thought about stopping your cancer medication. Oncologists would far rather manage the symptom than lose the treatment, and this is the single most important thing to disclose.

Getting to a menopause clinic or a specialist can itself take time, and our reporting on why specialist waits run as long as they do explains where the delays sit. Treatment can also be isolating in ways nobody warns you about, which our piece on the health effects of loneliness addresses directly.

What does this treatment cost in Canada?

That is the open question. A Bayer spokesperson said elinzanetant is not currently publicly funded in Canada and did not provide a price, so the treatment cost in Canada depends for now on private insurance and what your care team can arrange.

Practically, expect coverage to be a conversation involving you, your insurer and your oncology team rather than something settled at the pharmacy counter. Ask your care team whether a manufacturer patient support programme exists, since these are common for newly authorized medications before public funding decisions are made. Public funding decisions in Canada typically follow authorization by a considerable margin.

Frequently Asked Questions

What is a hot flash and why does it happen?

A sudden sensation of heat, usually across the face, neck and chest, often with sweating and a flushed appearance. When estrogen falls, neurons involved in regulating body temperature can become hyperactive and misread normal conditions as overheating, triggering the body's cooling response. A moderate episode involves heat and sweating. A severe one stops you mid-task.

Is this medication a hormone?

No. Elinzanetant is non-hormonal and contains no estrogen. It works on neurokinin receptors in the brain rather than replacing hormones, which is precisely why it was developed for women who cannot use hormone replacement therapy, including those with a history of hormone-receptor positive breast cancer.

What are the most common side effects?

In the OASIS-4 trial, the most frequently reported were drowsiness during the day, fatigue and diarrhea. As with any newly authorized medication, the full safety profile is set out in the product monograph, and anything unexpected should be reported to your prescriber or pharmacist rather than managed by stopping the drug on your own.

Can you take it if you are not in treatment?

Elinzanetant was first authorized in Canada in July 2025 for moderate to severe symptoms in women going through menopause, so that indication already existed. The August 2026 decision extended authorization to women getting these symptoms from endocrine therapy. Whether it suits you is a prescribing decision for your own clinician.

Is it covered by insurance in Canada?

Bayer has confirmed it is not currently publicly funded in Canada and has not released a price. Private drug plans vary, so check your own policy and ask your care team about manufacturer support programmes. Public funding decisions usually come well after regulatory authorization, so coverage may change.

Your next step

If treatment side effects or menopause symptoms are wearing you down, they are worth raising rather than absorbing. Book with a family practice near you, talk it through with a pharmacist without an appointment, or find a walk-in clinic with a short wait. You can also compare providers across your province. For more plain-language health guides, browse the Medimap Health Hub.

This article is general information and is not medical advice. It does not replace an assessment by a qualified health professional, and nothing here should be used to start, stop or change any medication, including cancer treatment. For a medical emergency, call 911.