Madrid, Spain — Metamizole, commonly known by its brand name Nolotil, is widely used in Spain and some other countries as an effective painkiller, especially following surgery and for cancer patients. Praised for being stronger than ibuprofen yet perceived as safer, its use among Spaniards is prevalent. However, the drug faces scrutiny and bans in places like the UK, US, and over 40 other countries primarily because of its association with a severe side effect called agranulocytosis—a rare but potentially fatal condition that significantly lowers white blood cell counts, leaving individuals highly susceptible to infections.
Recent incidents involving British and Irish tourists experiencing severe reactions or even death after consuming Nolotil have reignited concerns. These cases highlight a puzzling observation: people from certain regions, particularly British, Irish, and Scandinavian, appear more vulnerable to the adverse effects of the drug.
The exact cause of this increased susceptibility remains under investigation. Scientific theories have primarily centered around the drug’s interaction with the immune system. One prevalent hypothesis is that metamizole may prompt the immune system to produce antibodies that only activate in the presence of the drug. These antibodies might mistakenly target and destroy white blood cells, weakening the body’s defense against infections.
Further research suggests that the by-products of Nolotil’s breakdown could behave as ‘haptens’, which are small molecules that latch onto white blood cells triggering an immune response that results in their destruction. Such reactions can vary based on demographics like age and gender, possibly because of differences in how these groups metabolize the drug.
However, findings from the largest genetic study to date involving metamizole, with 86 participants from countries including Spain, Germany, and Switzerland, did not corroborate the immune-related gene theory. Instead, it identified genetic variants linked to antioxidant pathways and blood cell production on chromosome 9 of affected patients, suggesting another potential genetic predisposition to metamizole-induced agranulocytosis that warrants further exploration.
The increasing popularity of metamizole, coupled with its expansive use in outpatient settings, where supervision is minimal, has led to a rising number of reported agranulocytosis cases. From about 10 cases in Germany in 1990, the numbers surged to more than 50 by 2012. Despite these figures, some medical experts argue that the advantages of Nolotil, such as its efficacy and lower organ toxicity compared to opioids, outweigh the risks.
Nevertheless, the growing concerns advocate for administering metamizole strictly in controlled medical environments. Doing so ensures immediate treatment with antibiotics if agranulocytosis develops, thus potentially saving lives. Despite practitioners’ reassurance about its general safety, the rising instances of life-threatening reactions in certain populations call for a comprehensive review and possibly more stringent monitoring when prescribing the drug.
The dilemma poses a critical question to the medical community and regulatory bodies: Is it prudent to continue the widespread use of a drug whose potential risks and genetic connections to serious side effects are not fully understood, especially when it poses a higher threat to specific visitor populations in countries like Spain where the medication remains popular?
As the scientific and medical communities continue to debate and investigate, the safety profile of metamizole remains a topic of significant concern, underscoring the complexity of balancing effective pain management with patient safety across diverse populations.