In Brief
| Metamizole (dipyrone) | |
|---|---|
| NNT at 500 mg oral | 2.4 (95% CI 1.8–3.1), moderate certainty |
| Volume of data | 5 studies, 288 participants; 143 on the 500 mg dose |
| Comparison with other analgesics | Absent from the review |
| Main risk | Agranulocytosis, classed «very rare» (up to 1 in 10,000) |
| Germany | Prescription since 1987 |
| Italy | Prescription, paid entirely by the patient |
| France | Not sold |
Metamizole is a rare case of a drug regarded simultaneously as a good analgesic and as the subject of a fifty-year argument. German doctors prescribe it often, France has no access to it, the United States withdrew it in 1977. The reason for the divergence has one name: agranulocytosis.
Here are both sides, honestly.
How Much Data There Actually Is
The 2016 Cochrane review gives an NNT of 2.4 (confidence interval 1.8–3.1) for 500 mg orally. Over 70% of participants got at least half their pain relieved, against 30% on placebo. Certainty of evidence: moderate.
A good figure. But the data behind it are slimmer than one might assume:
- The whole review covers eight studies and 809 participants.
- The NNT was calculated not on all of it, but on five studies and 288 participants.
- The 500 mg oral dose itself accounts for 143 people.
- The review replaces a withdrawn 2010 version — the previous one was retracted.
For comparison: etoricoxib has 798 participants on a single dose. Metamizole is the thinnest evidence base of the five.
Agranulocytosis: What It Is and How Likely
Agranulocytosis is a sharp fall in neutrophils, the cells that defend against bacterial infection. A person becomes defenceless against ordinary flora, and untreated the condition is life-threatening.
The German label classes the frequency as «very rare» — up to one case in 10,000. That is rare, with two features that make it contentious: the reaction is unpredictable, and it can arise at any point during treatment and shortly after it ends.
What the Regulator Changed in December 2024
On 9 December 2024 the German regulator issued an official notice, agreed with the European agency, on measures to reduce the consequences of this risk.
The most interesting part is what many expected and did not get: routine blood monitoring during treatment was dropped. Instead, contraindications and warnings were tightened, and the main weight was placed on informing the patient. The logic is that the reaction develops too fast to be caught by scheduled tests; the only person who can catch it is the patient who knows the signs.
Signs that mean stopping immediately:
- fever and chills with no clear cause;
- sore throat;
- painful changes to the mucous membranes — mouth, nose, throat, and also the genital and anal area.
If any appear, stop the drug and see a doctor the same day: a full blood count with differential is required. Treatment is not resumed until the result is in. If the diagnosis is confirmed, it is never resumed.
A specific trap, named in the notice itself: when the drug is taken for fever, or alongside antibiotics, the symptoms can be masked. Someone takes it for a temperature — and temperature as a warning sign disappears into that.
Where It Is Sold
- Germany — prescription since 1987 (Novalgin, Novaminsulfon and generics).
- Italy — registered (Novalgina and others), all forms on prescription, paid entirely by the patient.
- France — not sold: no valid authorisation.
- United States — withdrawn from the market in 1977.
That map is informative in itself: regulators in different countries, looking at the same data, reached opposite decisions.
The Bottom Line
Metamizole genuinely relieves pain well, and its reputation as a strong agent is not baseless. But behind the NNT of 2.4 sits less data than behind its neighbours, there is no comparison with other analgesics at all, and the principal risk is rare, unpredictable and potentially fatal.
That is not a reason to treat the drug as poison — German doctors prescribe it to millions. It is a reason to treat it differently from an over-the-counter painkiller: to know the signs that mean stopping at once, and not to take it long-term on your own initiative.
And if you live in France, the question resolves itself: the drug is not there.
About buying
The drug is in the catalogue: Novalgina (metamizole) 500 mg. No price is shown — prescription medicines are ordered through the chat, and the administrator confirms availability and cost. The prescribing stays with a doctor: this guide explains what is known about the drug, it does not replace a consultation.
Key facts
- NNT 2.4 (95% CI 1.8–3.1) for the 500 mg oral dose: over 70% got at least half their pain relieved, against 30% on placebo.
- The base is thinner than it looks: the figure rests on five studies and 288 participants, and the 500 mg oral dose itself covers 143 people.
- The review replaces a withdrawn 2010 version, and contains no direct comparison of metamizole with other analgesics at all.
- In the German label agranulocytosis is classed as «very rare» — up to 1 in 10,000.
- The regulator's notice of 09.12.2024 dropped routine blood monitoring, tightening contraindications and warnings instead.
- Germany and Italy: prescription-only. France: not sold.
