The problem is casual use, even for mild symptoms, for months or years.
Por décadas, o omeprazol tem sido um dos medicamentos mais consumidos no mundo, oferecendo alívio rápido para males cotidianos do estômago. Agora, pesquisadores de duas universidades paulistas revelam que o uso prolongado dessa droga compromete a absorção de minerais essenciais, elevando riscos de osteoporose e anemia — justamente quando a Anvisa, em novembro de 2025, liberou sua venda sem receita. O episódio coloca em tensão a conveniência do acesso e a prudência do uso consciente, lembrando que nem todo remédio familiar é inofensivo quando consumido além do tempo e sem orientação.
- Estudo conduzido em ratos por pesquisadores da Unifesp e da Faculdade de Medicina do ABC demonstrou que o omeprazol altera a distribuição de minerais vitais — cálcio, ferro, zinco e magnésio — no organismo, com sinais claros de risco ósseo e sanguíneo.
- O cálcio elevado no sangue dos animais tratados sugere que o mineral está sendo retirado dos ossos, um alerta silencioso para osteoporose futura; ao mesmo tempo, a queda de ferro aponta para risco de anemia.
- A decisão da Anvisa de liberar o omeprazol 20mg sem prescrição em novembro de 2025 amplia o acesso, mas preocupa especialistas que já observam um padrão crônico de automedicação que ultrapassa os 14 dias recomendados.
- Medicamentos da mesma classe, como pantoprazol e esomeprazol, podem ser ainda mais problemáticos por serem mais potentes e de ação mais prolongada, intensificando os efeitos sobre a absorção de nutrientes.
- Os pesquisadores não pedem o abandono do medicamento, mas insistem na necessidade de uso racional, acompanhamento médico e, em alguns casos, suplementação nutricional para compensar as deficiências geradas.
Pesquisadores da Universidade Federal de São Paulo e da Faculdade de Medicina do ABC publicaram um estudo que questiona o modo como milhões de pessoas utilizam o omeprazol. O trabalho, divulgado na revista ACS Omega, investigou o que acontece quando inibidores da bomba de prótons permanecem no organismo por meses ou anos — um padrão cada vez mais comum, apesar das recomendações médicas em contrário.
Conduzidos pelo professor Angerson Nogueira do Nascimento, os experimentos com ratos ao longo de 10, 30 e 60 dias revelaram distribuição anormal de minerais essenciais como ferro, cálcio, zinco e magnésio. O achado mais alarmante foi o acúmulo de cálcio no sangue, indicativo de que o mineral pode estar sendo retirado dos ossos — um sinal de risco futuro de osteoporose. Paralelamente, a queda nos níveis de ferro aponta para possível anemia. Alterações nas células do sistema imunológico também foram detectadas.
A pesquisadora Andréa Santana de Brito, cuja dissertação de mestrado embasou o estudo, destacou que o problema não é o medicamento em si — eficaz para úlceras, gastrite e refluxo —, mas seu uso casual e prolongado para sintomas leves como azia. O mecanismo da droga, ao bloquear a produção de ácido estomacal, interfere diretamente na absorção de minerais que dependem de um ambiente ácido para serem assimilados.
O contexto regulatório torna a publicação ainda mais urgente: em novembro de 2025, a Anvisa aprovou a venda do omeprazol 20mg sem receita médica. Embora a agência tenha limitado as embalagens a 14 dias e exigido alertas na rotulagem, os pesquisadores temem que a medida amplie a automedicação irresponsável. Medicamentos mais potentes da mesma classe, como pantoprazol e esomeprazol, podem representar riscos ainda maiores devido à sua ação mais prolongada no organismo.
Nogueira reforça que a solução está no uso racional e supervisionado, com avaliação individual da necessidade de suplementação. À medida que o omeprazol se torna mais acessível, as evidências sobre seus custos ocultos ganham relevância crescente para quem decide se automedicar.
Researchers at two major São Paulo universities have published findings that challenge how millions of people use one of the world's most common stomach medications. The study, conducted at the Federal University of São Paulo and the ABC School of Medicine, examined what happens when omeprazole and similar drugs stay in the body for months or years—a pattern that has become routine despite medical warnings against it.
Omeprazole belongs to a class of medications called proton pump inhibitors, drugs designed to reduce stomach acid and relieve ulcers, gastritis, and acid reflux. The drug works by blocking an enzyme responsible for the final stage of acid production in the stomach. For decades, it has been one of the most prescribed medications globally, and increasingly, people take it without a doctor's oversight, often for minor symptoms like occasional heartburn. The problem, according to the new research published in the journal ACS Omega, is that prolonged use interferes with how the body absorbs essential minerals.
The research team, led by professor Angerson Nogueira do Nascimento, conducted experiments on rats over periods of 10, 30, and 60 days to simulate different durations of human use. The results were striking. Animals receiving omeprazole showed abnormal distribution of critical minerals—iron, calcium, zinc, magnesium, copper, and potassium—throughout their bodies. Calcium accumulated in the bloodstream while iron levels dropped, a pattern that suggests risk of osteoporosis and anemia. The researchers also detected significant changes in immune system cells. The mineral imbalances were not random; they accumulated in the stomach and created dangerous imbalances in the spleen and liver.
The most concerning finding involved calcium. High levels in the blood typically indicate the mineral is being pulled from bone tissue, a warning sign for future bone loss. "The most troubling discovery was the significant increase in blood calcium in the animals, which may indicate an imbalance caused by mineral depletion from bones and a future risk of osteoporosis," Nogueira explained. "However, longer studies are needed to confirm this hypothesis." Researcher Andréa Santana de Brito, whose master's thesis formed the basis of the study, emphasized that the investigation expanded previous knowledge by including magnesium and zinc in the analysis—nutrients whose depletion had been less thoroughly documented.
The timing of this research is particularly significant because of a regulatory decision made just weeks before publication. In November 2025, Brazil's health authority, Anvisa, approved the sale of omeprazole 20 milligrams without a prescription. The agency framed this as promoting "safe and responsible use," noting that packaging would be limited to 14-day supplies and that clear labeling would warn against extended use. But researchers worry the decision will have the opposite effect. "This is not about demonizing the medication, which is effective for various gastric conditions," Brito cautioned. "The problem is its casual use, even for mild symptoms like heartburn, and for periods stretching months or years. Its adverse effects should not be ignored."
Omeprazole has been on the market for more than 30 years, and its widespread availability without medical supervision has created a pattern of misuse. People take it longer than recommended, often without realizing they are doing so. The drug's mechanism—blocking acid production—necessarily interferes with nutrient absorption because many minerals require acidic conditions in the stomach to be properly absorbed. Similar medications in the same class, like pantoprazole and esomeprazol, may pose even greater risks because they are more potent and longer-acting. Some take more than five days for the body to produce new proton pumps, compared to one to three days for omeprazole, potentially intensifying side effects.
Nogueira stressed that the solution is not to stop using these medications but to use them rationally and under medical guidance. "We emphasize the importance of rational use of these drugs and, in some cases, evaluating the need for supplementation," he said. "However, medical supervision is necessary to assess each case individually." The researchers acknowledge that the connection between proton pump inhibitors and nutrient absorption was already known, but their work provides more detailed evidence of how extensively these drugs disrupt mineral balance. As omeprazole becomes easier to obtain, that evidence may become increasingly important for people deciding whether to self-treat with a medication that carries hidden costs.
Notable Quotes
The most troubling discovery was the significant increase in blood calcium in the animals, which may indicate an imbalance caused by mineral depletion from bones and a future risk of osteoporosis.— Professor Angerson Nogueira do Nascimento, Federal University of São Paulo
This is not about demonizing the medication, which is effective for various gastric conditions. The problem is its casual use, even for mild symptoms like heartburn, and for periods stretching months or years.— Researcher Andréa Santana de Brito, Federal University of São Paulo
The Hearth Conversation Another angle on the story
Why does stomach acid matter so much for absorbing minerals? It seems like reducing it would be a straightforward benefit.
Acid isn't just there to cause problems—it's part of the chemistry that breaks minerals down into forms the intestines can actually absorb. When you suppress acid, you're not just quieting heartburn; you're changing the fundamental conditions your body needs to process iron, calcium, and other essentials.
The study used rats. How confident should we be that these findings apply to humans?
That's a fair question. Animal studies are a starting point, not proof. But the researchers were careful to design the timeline to mirror human use patterns—10, 30, 60 days to represent different lengths of treatment. The biological mechanisms are similar enough that the warning is worth taking seriously, even if we need longer human studies to confirm the full picture.
The regulatory agency says the 14-day limit is printed on the label. Isn't that enough protection?
Labels are only as effective as people's willingness to read and follow them. The real issue is that omeprazole has become so normalized—people inherit it from a doctor's prescription years ago and just keep refilling it, or they buy it over the counter for occasional heartburn and lose track of how long they've been taking it. A label can't enforce discipline that isn't there.
If someone has been taking omeprazole for years, what should they do?
That's exactly why the researchers emphasize medical supervision. You can't just stop these drugs abruptly—your stomach acid production needs time to rebound. But a doctor can assess whether you still need it, whether supplementation makes sense, and whether there are alternatives. The point isn't panic; it's informed decision-making with professional guidance.
Why did the agency approve over-the-counter sales if researchers were already warning about this?
The agency's reasoning was that limiting packages to 14-day supplies and requiring clear labeling would promote responsible use. But there's a gap between what a regulation intends and what actually happens in people's medicine cabinets. The researchers are essentially saying that gap is where the real risk lives.