The problem is the casual, unsupervised use that has become routine.
Uma equipe de pesquisadores brasileiros lança luz sobre um paradoxo silencioso da medicina moderna: um medicamento amplamente confiado para aliviar o sofrimento gástrico pode, quando usado além do tempo recomendado, comprometer os próprios alicerces do corpo — os ossos, o sangue e a imunidade. O estudo, publicado na ACS Omega, surge num momento delicado, logo após a Anvisa liberar o omeprazol para venda sem receita, ampliando o acesso mas também o risco do uso irrefletido. É um lembrete de que a fronteira entre remédio e risco raramente está impressa na embalagem.
- Camundongos tratados com omeprazol por até 60 dias apresentaram cálcio acumulado no sangue e ferro em queda — sinais de que os ossos estavam sendo esvaziados e a anemia, silenciosamente instalada.
- O mecanismo que torna o omeprazol eficaz — o bloqueio do ácido gástrico — é o mesmo que impede a absorção de minerais essenciais como ferro, cálcio, zinco e magnésio.
- Versões mais novas da mesma classe de medicamentos, como pantoprazol e esomeprazol, suprimem o ácido por mais de cinco dias seguidos, potencialmente intensificando os efeitos documentados.
- Em novembro de 2025, a Anvisa liberou o omeprazol 20mg sem prescrição, com embalagens limitadas a 14 dias — mas pesquisadores temem que a medida incentive a automedicação prolongada.
- Os cientistas não pedem o abandono do medicamento, mas insistem em algo mais difícil de garantir: que ele seja usado com supervisão médica, dentro do prazo seguro, e com suplementação mineral quando necessário.
Uma equipe da Universidade Federal de São Paulo documentou o que acontece quando o omeprazol — um dos medicamentos mais consumidos no Brasil — é usado por mais tempo do que os 14 dias recomendados. O estudo, publicado na ACS Omega, acompanhou camundongos divididos em dois grupos ao longo de 10, 30 e 60 dias. Quanto mais prolongado o uso, mais desequilibrado ficava o metabolismo mineral dos animais: o cálcio subia no sangue enquanto o ferro despencava, e alterações apareciam no baço, no fígado e nas células imunes.
O paradoxo está no próprio mecanismo do remédio. O omeprazol bloqueia a bomba de prótons, reduzindo o ácido gástrico e aliviando úlceras, gastrite e refluxo. Mas esse mesmo ácido é essencial para absorver minerais como ferro, cálcio, zinco e magnésio. Ao suprimi-lo, o corpo perde a capacidade de extrair esses nutrientes dos alimentos. O coordenador do estudo, Angerson Nogueira do Nascimento, apontou o cálcio elevado no sangue como o achado mais preocupante: provavelmente, o mineral estava sendo retirado dos ossos para compensar a deficiência — um prenúncio de perda óssea futura.
A pesquisadora Andréa Santana de Brito foi direta sobre o verdadeiro problema: não é o medicamento em si, mas a forma como ele é usado. No Brasil, muitas pessoas tomam omeprazol por meses ou anos, sem acompanhamento médico, para sintomas leves como azia ocasional. As deficiências minerais se acumulam sem aviso, e a perda óssea avança sem sintomas até que uma fratura ocorra.
Esse cenário ganhou contornos mais urgentes em novembro de 2025, quando a Anvisa autorizou a venda do omeprazol 20mg sem receita, com embalagens limitadas a duas semanas. A agência argumentou que a medida promoveria o uso racional. Brito discordou, temendo que o acesso facilitado incentive a automedicação além do prazo seguro. Os pesquisadores não pedem que as pessoas deixem de usar o medicamento — pedem algo mais simples e mais difícil: que o usem como indicado, com supervisão médica, e com a consciência de que alívio imediato não é sinônimo de segurança.
A team of Brazilian researchers has documented a troubling pattern in how a widely used heartburn medication affects the body when taken longer than doctors recommend. The study, published in the journal ACS Omega, examined what happens when omeprazole—a proton pump inhibitor—stays in the system for weeks or months instead of the standard two-week window. What they found in mice suggests that extended use disrupts the body's ability to absorb essential minerals, potentially setting the stage for osteoporosis and anemia.
The experiment was straightforward in design but revealing in results. Scientists at the Federal University of São Paulo divided adult mice into two groups: one receiving omeprazole, the other a placebo. They tracked the animals over 10, 30, and 60 days to simulate what prolonged human use might look like. The longer the mice took the drug, the more their mineral balance shifted. Calcium accumulated in the bloodstream while iron levels dropped—a pattern that suggests the body was pulling calcium from bones to compensate, leaving skeletal tissue weakened. Changes also appeared in the spleen, liver, and immune cells.
Omeprazole works by shutting down the proton pump, the mechanism that produces stomach acid. Less acid means relief from ulcers, gastritis, and reflux. But stomach acid also helps the body absorb nutrients like iron, calcium, zinc, magnesium, copper, and potassium. Block the acid, and you block absorption. Angerson Nogueira do Nascimento, one of the study's coordinators, emphasized that the calcium finding was the most concerning. The mineral's rise in the blood, he explained, likely means it was being leached from bone—a harbinger of future bone loss. But he cautioned that longer studies in humans would be needed to confirm the mechanism.
The research team noted that newer versions of this drug class—pantoprazol and esomeprazol—may pose even greater risks. These molecules are more potent and linger longer in the body. While omeprazole allows new proton pumps to form within one to three days, the newer drugs can take more than five days. That extended suppression could intensify the side effects the team documented. The findings themselves were not entirely new; doctors have long known that proton pump inhibitors interfere with nutrient absorption. But this study expanded the picture by examining minerals like magnesium and zinc that had received less attention.
The real concern, according to researcher Andréa Santana de Brito, is not the medication itself but how it is being used. In Brazil and elsewhere, people take omeprazole for months or years, often for minor symptoms like occasional heartburn, without medical oversight. The drug works, so they keep taking it. The problem is invisible—mineral deficiencies accumulate quietly, and bone loss accelerates without symptoms until a fracture occurs. Brito was careful to say the goal was not to demonize the medication, which has genuine value for serious gastric conditions. The issue is casual, unsupervised, indefinite use.
That concern took on new urgency in November 2025, when Brazil's health regulator, Anvisa, changed the rules around omeprazole. The 20-milligram version is now available over the counter without a prescription. The agency limited over-the-counter packages to a two-week supply and argued the move would promote rational use. Brito disagreed. She worried the easier access would encourage self-medication and extended use that ignores the 14-day guideline. Nascimento echoed the call for medical supervision and suggested that some patients might need mineral supplementation to offset the drug's effects. The researchers were not asking people to stop taking omeprazole. They were asking for something simpler and harder: that people use it as directed, under a doctor's eye, and understand that convenience and symptom relief are not the same as safety.
Citações Notáveis
The most concerning finding was the significant increase in calcium in the animals' bloodstream, which may indicate an imbalance with mineral being withdrawn from bones and future osteoporosis risk.— Angerson Nogueira do Nascimento, Federal University of São Paulo
The problem is not demonizing the medication, which is effective for various gastric conditions, but rather the casual use for mild symptoms like heartburn, taken for months or years without medical supervision.— Andréa Santana de Brito, Federal University of São Paulo
A Conversa do Hearth Outra perspectiva sobre a história
Why does the study focus on mice rather than looking at people who've already taken omeprazole for years?
Mice let you control everything—the dose, the duration, the diet, what you measure. You can't do that with humans ethically. But the patterns they found—calcium rising, iron falling, immune cells changing—those are biological signals worth taking seriously.
The researchers seem careful not to say omeprazole is bad. Why the caution?
Because it isn't bad. For someone with a bleeding ulcer or severe reflux, this drug is a lifesaver. The problem is that people with mild heartburn take it for years without thinking. The drug works so well they forget they're taking it.
Anvisa says the over-the-counter version is limited to two weeks. Doesn't that solve the problem?
In theory, yes. In practice, people buy another package. Or they buy it at a different pharmacy. The limit is on the package, not on the person. And there's no doctor asking why they need it again.
What would responsible use actually look like?
You take it for two weeks. If your symptoms come back, you see a doctor instead of just refilling. The doctor figures out if you have reflux disease or if you're just stressed and eating late. Those need different answers.
Should people already taking it long-term be worried?
Not panicked, but attentive. Get your bone density checked. Ask your doctor about iron and calcium levels. Maybe you need supplements. Maybe you need a different approach altogether. The point is to know what's happening in your body, not to guess.