Answering the Question: What does metamizole treat?

October 8, 2025 •

4 min read

While banned in countries like the United States, United Kingdom, and Australia, metamizole is a popular painkiller in many parts of the world, including Germany, Spain, and Brazil [1.2.1, 1.2.4, 1.5.1]. So, what does metamizole treat that justifies its use despite the risks?

Quick Summary

Metamizole is a potent non-opioid drug used for severe pain, high fever, and smooth muscle spasms [1.2.1, 1.9.1]. Its use is controversial due to its link to agranulocytosis, a rare but life-threatening blood disorder [1.4.2].

Key Points

Primary Indications: Metamizole is used for severe acute pain (like post-operative or colic), cancer pain, and high fever that doesn't respond to other drugs [1.4.5, 1.9.4].
Spasmolytic Action: It has a unique muscle-relaxing effect, making it highly effective for cramping visceral pain from kidney stones or gallstones [1.2.4, 1.9.1].
Agranulocytosis Risk: The main controversy is its link to agranulocytosis, a rare but potentially fatal drop in white blood cells, which led to its ban in the US, UK, and other nations [1.4.5, 1.5.1].
Global Status Disparity: While banned in many Western countries, it remains a popular and widely prescribed analgesic in places like Germany, Spain, Brazil, and Russia [1.2.4, 1.5.1].
Mechanism of Action: It is believed to work by inhibiting COX enzymes and acting on central pain pathways, including the cannabinoid and opioid systems [1.3.2, 1.3.5].
Comparison to NSAIDs: It has weaker anti-inflammatory effects but better gastrointestinal tolerability compared to traditional NSAIDs like ibuprofen and aspirin [1.3.2, 1.8.5].
Medical Supervision: Due to its significant risks, metamizole should only be used under strict medical guidance, with patients aware of the warning signs of agranulocytosis [1.4.3].

What is Metamizole?

Metamizole, also known as dipyrone, is a non-opioid analgesic (pain reliever), antipyretic (fever reducer), and spasmolytic (muscle spasm reliever) [1.2.4, 1.9.1]. First patented in Germany in 1922, it was marketed under brand names like Novalgin and Analgin [1.2.1]. It is considered a powerful medication for conditions that do not respond well to other treatments [1.4.5]. However, its safety profile, particularly its association with a rare but serious condition called agranulocytosis, has led to its withdrawal from the market in many countries, including the United States, Canada, the UK, and Australia [1.5.1, 1.5.5]. Despite this, it remains widely used in other parts of the world, such as the European Union, Latin America, Russia, and Israel, where it is often available over-the-counter or by prescription [1.2.1, 1.5.1].

How Does Metamizole Work?

The exact mechanism of action for metamizole is complex and not fully understood [1.3.4]. It is a prodrug, meaning it is converted into active metabolites in the body [1.3.3]. These metabolites are believed to produce its therapeutic effects [1.3.1]. The primary mechanisms are thought to include:

Inhibition of Prostaglandin Synthesis: Like many non-steroidal anti-inflammatory drugs (NSAIDs), metamizole inhibits cyclooxygenase (COX) enzymes, which are involved in producing prostaglandins. Prostaglandins are chemicals that cause pain and inflammation [1.3.2]. However, metamizole's effect on COX enzymes is weaker than traditional NSAIDs, which may explain its more favorable gastrointestinal tolerability [1.3.2, 1.8.5].
Central Nervous System Activity: It is believed to act on the central nervous system, including the brain and spinal cord, potentially activating endogenous opioid and cannabinoid systems to help block pain signals [1.3.2, 1.3.5].
Spasmolytic Effect: Uniquely among many analgesics, metamizole has a spasmolytic effect, meaning it can relieve cramps and spasms in smooth muscles [1.2.4]. This makes it particularly effective for certain types of pain, such as colic [1.9.2].

What Conditions Does Metamizole Treat?

Due to its risk profile, metamizole is generally reserved for severe conditions where other treatments are unsuitable or have failed [1.4.5].

Severe Acute and Postoperative Pain

Metamizole is highly effective for managing moderate to severe acute pain, especially following surgery [1.2.2]. Studies show that a single 500 mg oral dose can provide significant pain relief for about 70% of patients with postoperative pain, compared to only about 30% with a placebo [1.7.1]. It is also used for pain from acute injuries and in orthopedics, where it has been found to be non-inferior to other common analgesics and can reduce the need for rescue opioids [1.7.2].

Visceral and Colic Pain

Thanks to its spasmolytic properties, metamizole is a drug of choice in many regions for treating visceral pain, which originates from internal organs [1.2.4]. This includes colicky pain from the gastrointestinal tract, biliary passages (gallstones), and the urinary tract (kidney stones) [1.3.1, 1.8.1, 1.9.1]. It works by relaxing the smooth muscle contractions that cause this intense, cramping pain [1.2.4].

High Fever (Hyperpyrexia)

Metamizole is a potent antipyretic, used for treating high fever that does not respond to other measures or medications like paracetamol or ibuprofen [1.4.5, 1.2.5]. In children, its effectiveness in reducing high temperature is comparable to that of ibuprofen [1.2.5].

Cancer Pain and Other Chronic Pain

In some protocols, metamizole is used in the management of cancer-related pain [1.2.2]. A study comparing oral metamizole to oral morphine for cancer pain found comparable pain relief, though morphine had a faster onset [1.3.2]. It is also sometimes used for other acute and chronic pain conditions when other analgesics are not indicated [1.3.1].

The Agranulocytosis Controversy

The primary reason metamizole is banned in many countries is its link to agranulocytosis, a rare but life-threatening condition where the body's count of neutrophilic granulocytes (a type of white blood cell) drops to dangerously low levels [1.4.4, 1.4.5]. This severely compromises the immune system, leaving the patient vulnerable to fatal infections [1.4.3].

The estimated incidence of metamizole-induced agranulocytosis (MIA) varies dramatically across studies, from as low as 0.96 cases per million people per year to as high as one case per 1,439 prescriptions [1.4.5]. This discrepancy is a central point of the global debate on its safety. The risk is not dose-dependent and can occur at any time during treatment, even in patients who have used the drug before without issue [1.4.3]. Symptoms to watch for include fever, chills, sore throat, and ulcers in the mouth or throat [1.4.5]. Due to this risk, the European Medicines Agency (EMA) has emphasized that patients should be educated on these symptoms and seek immediate medical attention if they appear [1.4.3].

Metamizole vs. Common Analgesics

Metamizole has a unique profile compared to other common pain relievers.


Feature	Metamizole	Ibuprofen	Paracetamol (Acetaminophen)	Aspirin
Primary Use	Severe pain, colic, high fever [1.4.5]	Mild to moderate pain, inflammation [1.2.1]	Mild to moderate pain, fever [1.2.1]	Pain, fever, anti-platelet effect [1.2.1]
Mechanism	COX inhibition, central pathways [1.3.2]	COX-1 & COX-2 inhibition [1.3.2]	Primarily central COX inhibition [1.3.2]	Irreversible COX inhibition [1.3.2]
Anti-inflammatory	Weak [1.4.5]	Strong [1.2.1]	Very weak [1.3.2]	Strong (at high doses) [1.2.1]
Spasmolytic Effect	Yes [1.2.4]	No [1.2.4]	No [1.2.4]	No [1.2.4]
Primary Risk	Agranulocytosis, liver injury [1.2.1, 1.4.5]	GI bleeding, kidney damage [1.2.1]	Liver toxicity in overdose [1.2.1]	GI bleeding, Reye's syndrome in children [1.2.1]
Status in USA/UK	Banned [1.5.1]	Over-the-counter [1.2.1]	Over-the-counter [1.2.1]	Over-the-counter [1.2.1]

Conclusion

Metamizole is a potent medication that treats severe pain (especially postoperative and colic-related) and high, refractory fever [1.4.5]. Its unique spasmolytic properties make it particularly effective for visceral pain, setting it apart from other non-opioid analgesics [1.2.4]. However, its benefits must be carefully weighed against the rare but serious risk of agranulocytosis, a factor that has led to sharply divided regulatory opinions worldwide [1.5.1, 1.5.2]. In countries where it is available, its use is often restricted to specific, severe indications under medical supervision, underscoring its status as a powerful but risky therapeutic tool [1.4.5].

For more information, you can review the European Medicines Agency's safety recommendations: https://www.ema.europa.eu/en/news/ema-recommends-measures-minimise-serious-outcomes-known-side-effect-painkiller-metamizole

Frequently Asked Questions

No, metamizole is a non-opioid analgesic. It belongs to the pyrazolone class of drugs and works differently from opioids like morphine or oxycodone [1.3.2, 1.7.2].

Metamizole was withdrawn from the market in the US, UK, and several other countries because of its association with agranulocytosis, a rare but potentially fatal blood disorder where white blood cell counts drop to dangerous levels [1.5.1, 1.5.5].

There is no difference; they are two names for the same active substance. 'Dipyrone' is another common name used for metamizole in many parts of the world [1.2.1].

This depends on the country. In some countries like Brazil, Mexico, and Russia, it is available over the counter. In others, like Germany and Spain, it requires a prescription. It is not available at all in the US, UK, or Canada [1.2.1, 1.5.1].

The initial symptoms are often non-specific and can include fever, chills, exhaustion, and a sore throat. Ulcerations in the mouth, nose, or throat can also be a key sign. If these symptoms appear, medical attention should be sought immediately [1.4.3, 1.4.5].

Yes, metamizole is used to treat headaches, including migraines, in countries where it is available [1.2.2]. However, in some regions, this may be considered an off-label use if not specifically approved for that purpose [1.4.5].

Common brand names for metamizole include Novalgin, Analgin, Nolotil, and Buscapina Compositum (in combination). There are hundreds of brand names worldwide [1.2.2, 1.8.4].