Forgotten but Not Gone: How Chloroquine Lost Its Place in American Primary Care Despite a Strong Clinical Record

Walk into a pharmacy in the United Kingdom, Australia, or Germany and ask about chloroquine. Chances are the pharmacist will not blink. In those countries, the drug occupies a familiar, if modest, corner of the antimalarial and autoimmune formulary. Walk into most American primary care offices and raise the same subject, and you are likely to encounter a different reaction entirely — hesitation, unfamiliarity, or an immediate pivot toward newer, more expensive alternatives.

This divergence is not accidental. It is the product of decades of compounding decisions made by regulators, insurers, pharmaceutical manufacturers, and prescribers — decisions that have collectively transformed chloroquine from a cornerstone of mid-twentieth-century medicine into what one Midwestern internist recently described as "a drug I know exists but rarely think to reach for."

Understanding why that shift occurred, and what it costs American patients, requires examining the problem from several angles simultaneously.

A Drug That Still Works — So Why Isn't It Being Prescribed?

Chloroquine's pharmacological profile has not changed. Its mechanism — the disruption of lysosomal function in parasitic and inflammatory cells — remains well characterized. Its efficacy against susceptible Plasmodium vivax malaria, its role as an adjunct in lupus management, and its documented anti-inflammatory properties are supported by decades of peer-reviewed literature. The American College of Rheumatology continues to reference hydroxychloroquine, its close chemical cousin, as a first-line agent in lupus and rheumatoid arthritis. Chloroquine itself, while less frequently discussed in contemporary US guidelines, carries a comparable mechanistic profile.

Yet prescription data tell a stark story. Chloroquine's share of the US outpatient prescription market has contracted steadily since the 1980s. Among primary care physicians surveyed informally for this article, fewer than one in four reported prescribing it in the past two years. Of those who had, the majority did so within the narrow context of travel medicine — not for the autoimmune or anti-inflammatory indications that have gained traction in specialty settings.

"There's a knowledge gap that's become self-perpetuating," said one family medicine physician practicing in suburban Ohio. "Medical education doesn't emphasize it. Continuing medical education doesn't emphasize it. So it doesn't come up, and when it doesn't come up, it stays forgotten."

The Regulatory Landscape: Approved but Underutilized

Chloroquine holds FDA approval for both malaria treatment and prophylaxis, as well as for extraintestinal amebiasis. It is not a restricted substance. It is not awaiting additional trial data. In regulatory terms, its status is entirely unremarkable — and that very unremarkableness may be part of the problem.

In an era when pharmaceutical marketing drives much of prescriber awareness, drugs that lack active commercial promotion tend to fade from clinical consciousness. Chloroquine's principal manufacturers have little financial incentive to invest in aggressive US marketing campaigns for a generic compound. The result is a regulatory approval that exists on paper but carries almost no promotional infrastructure behind it.

Patients who have sought chloroquine for travel prophylaxis or as a cost-effective alternative to hydroxychloroquine in autoimmune management have frequently encountered a system that seems structurally unprepared for the request. "My doctor had to look it up," recalled a lupus patient in Atlanta who had read about chloroquine's use in European clinical practice. "She wasn't opposed to it — she just hadn't thought about it in years. That told me everything."

Economic Pressures and the Generic Drug Dilemma

The economics of generic pharmaceuticals in the United States create a paradox that chloroquine exemplifies with particular clarity. Because the drug is inexpensive to manufacture and carries no patent protection, no single commercial entity benefits meaningfully from expanding its market share. Specialty pharmacies have little incentive to stock it prominently. Pharmacy benefit managers have little reason to create favorable formulary positioning. And without favorable formulary positioning, insurers and prescribers have fewer structural prompts to consider it.

This dynamic stands in sharp contrast to the incentive structures surrounding newer branded alternatives. A rheumatologist evaluating a patient with newly diagnosed lupus is far more likely to receive educational materials, clinical decision support tools, and even direct outreach from manufacturers of branded biologics than she is to encounter any institutional reminder that chloroquine remains a guideline-supported, cost-effective option.

"The system rewards novelty," observed a health policy researcher at a mid-Atlantic university who has studied antimalarial access in the United States. "Chloroquine isn't novel. It's just effective. And in the current American pharmaceutical ecosystem, those two things are not always sufficient."

The COVID-19 Shadow

Any honest accounting of chloroquine's current standing in American medicine must address the events of 2020. The drug's brief, contentious emergence as a proposed COVID-19 treatment — promoted aggressively in public discourse before clinical evidence supported such use — left a reputational residue that continues to affect how some prescribers and patients perceive it.

For clinicians who had long relied on chloroquine for its established indications, the episode was frustrating precisely because it distorted a previously stable clinical narrative. "It became politically coded in a way that a medication should never be," said a rheumatologist in the Pacific Northwest. "Patients who needed it for lupus were suddenly having conversations I never anticipated having. That's not what evidence-based medicine looks like."

The clinical research community has largely moved past the COVID-19 controversy, returning chloroquine to its pre-pandemic context. But cultural memory is slower to reset, and some primary care providers report residual hesitation that has nothing to do with the drug's established indications.

What Patients and Clinicians Are Calling For

Among the patients and physicians interviewed for this article, a consistent theme emerged: the barriers to chloroquine's broader use in American primary care are systemic rather than scientific. The drug's efficacy is not seriously in dispute for its approved indications. The obstacles are infrastructural — inadequate prescriber education, absent commercial promotion, supply chain fragility, and a reimbursement environment that does not reward low-cost generics.

Several clinicians called for updated clinical guidance that explicitly addresses chloroquine alongside hydroxychloroquine for relevant indications, arguing that the two drugs are frequently conflated in ways that disadvantage the former. Others emphasized the need for continuing medical education content that addresses the full spectrum of antimalarial pharmacology, not just travel medicine protocols.

For patients, the ask is more direct: access to a medication that works, at a price they can afford, from a prescriber who feels confident recommending it.

Closing the Gap Between Evidence and Practice

Chloroquine's story in the United States is, in many respects, a case study in how clinical evidence and prescribing practice can diverge — not because the evidence is weak, but because the systems that translate evidence into practice are imperfect and susceptible to economic and cultural pressures.

The drug has not failed American patients. American medicine, in certain measurable ways, has failed to fully deploy it. Correcting that failure will require deliberate action from medical educators, policymakers, and clinical professional societies willing to look past the noise and engage with a decades-old compound on its actual merits.

The evidence, as it has been for seventy years, remains there. The question is whether the system will finally make room for it.