Optalgin, more commonly known as metamizole, and marketed under the names of Dipyrone, Analgin, Novalgin, Algocalmin, and Melubrin is a non-opioid pain reliever. Metamizole is provided in tablet form and ampules for injection. It is injected primarily after surgery to treat acute pain. The use of this drug is restricted in several countries and is not licensed in the United States. There is a great amount of controversy about the incidence of severe side effects with metamizole and its therapeutic value. Metamizole has been sold since 1922. A review article published in the July 2000 issue of the journal “Casopis Lekaru Ceskych” from the Czech Republic reports that metamizole is effective in reducing pain and fever in adults and children and is less toxic than other available nonsteroidal anti-inflammatory drugs, also known as NSAIDs, but studies published in other journals have found that the drug can be harmful in large doses.
Gastrointestinal Toxicity
A large multicenter study published in the journal “Lancet” reported that dipyrone did not increase the risk of gastrointestinal bleeding. The most common use of dipyrone is to treat severe abdominal pain.
Kidney Toxicity
A study in the journal of “Nephrology, Dialysis and Transplantation” reported that large doses of metamizole can cause acute inflammation of the kidneys. Another study in the “Archives of Disease in Childhood” reported that an overdose of dipyrone resulted in renal insufficiency.
Severe Blood Disorders
Agranulocytosis and aplastic anemia are severe acute blood disorders characterized by a marked decrease in blood cells, especially white blood cells, that can be fatal. A 2009 review of metamizole reported that the frequency of severe decreases in white blood cells while taking metamizole was 1 in 1,439. The authors of this study strongly advised against the use of metamizole. However, a large prospective study published in a Polish journal reported an incidence of only 0.25 cases of aplastic anemia per 1 million persons per day of treatment and concluded this incidence is much less than that reported for NSAIDs.
References
- “Casopis Lekaru Ceskych”; Metamizol--A New effective Analgesic with a Long History; Z. Fendrich; July 19, 2000
- “Lancet”; Upper Gastrointestinal Bleeding in Relation to Previous use of Analgesics and Non-steroidal Anti-inflammatory Drugs; J.R. Laporte et al; 1991
- “Nephrology, Dialysis, Transplantation”; Noramidopyrine (Metamizol) and Acute Interstitial Nephritis; Ibrahim Abu-Kishk et al; 1998
- “Archives of Disease in Childhood”; Transient Renal Insufficiency Following Dipyrone Overdose; Ibrahim Abu-Kishk et al; November 2009
- “Deutsches Aerzteblatt International”; Advise Against Metamizole; Joachim Neumann; Jan. 23, 2009
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