Important notice

Please read this once. It is short, and it matters.

This is not medical advice

Nothing here is medical advice, diagnosis, or treatment, and reading it creates no clinician–patient relationship of any kind. It is a research summary written for personal use and shared in case it is useful to others.

Do not start, stop, change, or dose any treatment on the basis of this document. Several treatments discussed in it carry serious, documented risks — verapamil has real cardiac-conduction hazards and the document records a series in which 41% of patients had never had an ECG; lithium requires serum monitoring; ergots have absolute contraindications; some substances discussed are controlled in most jurisdictions. Those risks are described here because leaving them out would make the document dishonest, not because any of it is a recommendation.

Take decisions with a clinician who knows your history, your other conditions and your other medicines.

It is a living document, and it will sometimes be wrong

This reference is revised on a rolling basis: a weekly research pass feeds a monthly update, and material is added, corrected and removed each cycle. That process is what keeps it current, and it is also the reason it will sometimes be out of date, incomplete, or simply mistaken.

Substantial care has gone into accuracy — every claim carries an evidence tag, sources are linked, and contradictions between sources are shown rather than smoothed over. None of that makes it authoritative. Where a claim matters to a decision you are making, follow the citation to the source and read the source.

The document keeps its own list of things it is unsure about. The Unresolved Conflicts, Open Questions and Editor’s Queries sections are not disclaimers bolted on afterwards — they are part of the method, and they are worth reading.

What the evidence tags mean

Every claim is tagged with where it came from. The tag describes provenance, not endorsement, and a tag is not a quality score:

• peer-reviewed — published in the reviewed literature. Still capable of being wrong, underpowered, or contradicted by the next study.
• preprint / trial — trial registrations and preprints, not yet reviewed.
• official / policy — regulator, government and guideline documents.
• citizen science — structured patient-community surveys and datasets.
• community report — patient self-report and community consensus. Included because patterns in anecdote are worth recording, and labelled honestly so you can weigh them accordingly. Not evidence of efficacy.
• historical — of historical or cultural interest; frequently superseded.

Independence

This is a private project with no institutional affiliation. It is not connected to, funded by, endorsed by, or written on behalf of any clinic, hospital, patient charity, professional body, device manufacturer or pharmaceutical company. There is no advertising, no sponsorship, no affiliate arrangement and nothing for sale.

Where the document is critical of a company, a regulator or a guideline, that is a reading of the sources cited, offered in good faith.

Access, legality and jurisdiction

Availability, licensing, subsidy and legal status for the treatments discussed differ substantially between countries, and the document covers only a handful in detail. Nothing here should be read as encouraging the acquisition or use of any substance or device outside the law where you live, or outside medical supervision.

About the assistant on this site

The question-answering assistant is restricted to the text of this document. It has no access to the internet and is instructed to answer only from the material here, and to say so plainly when the answer is not in the text rather than filling the gap from general knowledge.

It can still get things wrong: it can misread a passage, attach a figure to the wrong study, or miss context that sits elsewhere in the document. Treat its answers as a way of finding the relevant passage, not as a substitute for reading it. Every answer links to its sources — follow them.

If you are in crisis

Cluster headache carries a documented burden that this document does not soften. If you are thinking about harming yourself, please reach a person now.

• Emergency services — 000 (Australia) · 999 (UK) · 911 (US & Canada) · 112 (EU and much of the world)
• Australia — Lifeline 13 11 14 (24/7) · Beyond Blue 1300 22 4636
• United Kingdom — Samaritans 116 123 (free, 24/7)
• United States & Canada — Suicide & Crisis Lifeline 988
• Anywhere else — findahelpline.com lists free, confidential services by country

If you are the partner, parent or friend of someone with this condition, those lines are for you too. Watching it is its own kind of hard, and it is a common reason people call.

Corrections

If something here is wrong, it should be fixed. Corrections and better sources are genuinely welcome — the assistant on this site can log a question or a correction for the next research pass, or you can raise it directly.

No warranty

This document is provided as is, without warranty of any kind, express or implied, including any warranty of accuracy, completeness, or fitness for a particular purpose. To the fullest extent permitted by law, the author accepts no liability for any loss, injury or damage arising from the use of, or reliance on, anything in it. You use it at your own risk.

Nothing in this notice limits any liability that cannot lawfully be excluded, including under the Australian Consumer Law.