Non-hormonal treatments for hot flashes: what has evidence

Who this is for

Hormone therapy remains the most effective treatment for vasomotor symptoms. Non-hormonal options matter for the substantial group who cannot use it, including many women with a history of hormone-sensitive breast cancer, and for those who prefer not to.

The important point is that not being able to take hormone therapy does not mean having no options, which is what many women are effectively told.

The newer mechanism-based drugs

The hypothalamic neurons that become hyperactive without estrogen's restraint have been identified, and they signal partly through the neurokinin 3 receptor. Blocking that receptor reduces the signal that triggers a flash.

Neurokinin 3 receptor antagonists are the first genuinely new mechanism in this field in decades and have trial evidence for reducing the frequency and severity of moderate to severe vasomotor symptoms without hormones.

They require monitoring of liver function, and availability and licensing vary by country. This is a prescribing conversation rather than something to seek out from a description.

Repurposed medications with evidence

Several medicines developed for other purposes have trial support for vasomotor symptoms:

• Certain SSRI and SNRI antidepressants, at doses lower than those used for depression
• Gabapentin, with evidence particularly for night-time symptoms
• Clonidine, a blood pressure medicine, with modest evidence and a less favourable side effect profile
• Oxybutynin, with evidence in trials though anticholinergic effects limit its use

An important interaction to know about

Some SSRIs, notably certain ones, inhibit the enzyme that converts tamoxifen into its active form, potentially reducing its effectiveness.

This matters directly because the group most likely to need a non-hormonal option for hot flashes overlaps heavily with the group taking tamoxifen. Anyone on tamoxifen should raise this specifically when a non-hormonal option is being chosen, because alternatives without the interaction exist.

Non-drug options, and what does not work

Cognitive behavioural therapy has reasonable evidence, and it works in a particular way worth understanding: it does not reduce the number of flashes, it reduces how much they interfere and how distressing they are. That is a legitimate outcome and a realistic expectation to set.

Clinical hypnosis has trial evidence in this area. Weight loss where relevant, and stopping smoking, are both associated with fewer symptoms.

Evidence for black cohosh, evening primrose oil and most other marketed supplements is weak or absent, and black cohosh has been associated with rare liver injury. Acupuncture trials generally show improvement that does not separate from sham acupuncture.

When to see someone

Ask specifically what non-hormonal prescription options are available where you live, because they are often not mentioned unless requested, and availability of the newer class varies.

If you have had breast cancer, ask for a discussion that includes your oncology team. There are usually more options than the initial answer suggests.