There’s Just One Drug to Treat Monkeypox. Good Luck Getting It.

The only drug available to treat monkeypox is so difficult to access that just a fraction of the nearly 7,000 patients in the United States have been given it.

Health officials have designated tecovirimat, also called Tpoxx, an “investigational drug,” which they say means it cannot be released from the strategic national stockpile without a series of convoluted bureaucratic steps. But most doctors do not have the time or resources to fill out the required 27-page application or to provide the detailed patient information.

It doesn’t have to be this way, experts say: There is no law preventing federal officials from changing those rules and making the drug more widely available.

The Food and Drug Administration approved tecovirimat as a smallpox treatment in 2018, based on safety data in people and efficacy data in primates — which, for the purposes of the trial, actually were infected with monkeypox. The so-called animal rule allows the agency to approve drugs when testing them in people would be unethical.

Until the current outbreak, tecovirimat was given only rarely to monkeypox patients. As a smallpox treatment, its use against monkeypox is considered experimental. But vaccines developed for smallpox have been assumed to be effective against both diseases. Why not the treatment?

Experts say the F.D.A.’s restrictions are a policy choice that can be quickly altered.

“The bureaucracy of gaining access to Tpoxx is excessive given the crisis the U.S. is facing with monkeypox,” said Larry O. Gostin, an expert on public health law and director of the O’Neill Institute for National and Global Health Law at Georgetown University.

“The law gives the agency considerable flexibility to use scientific assessments to ensure those in need get the medication that can help them,” he added.

The Department of Health and Human Services on Thursday declared monkeypox a national health emergency. But Secretary Xavier Becerra did not take an additional step that would have allowed the F.D.A. to grant emergency use authorizations for vaccines and treatments, as the agency did during the coronavirus pandemic.

In an article published in the New England Journal of Medicine on Wednesday, federal health officials defended their decision to treat tecovirimat as an investigational drug.

While acknowledging that animal data was promising and that the drug seemed safe in healthy patients, they wrote that, without large clinical trials, “we will not know whether tecovirimat would benefit, harm or have no effect on people with monkeypox disease.”

“At this time, it’s unclear if or how well this drug works for monkeypox patients,” said Kristen Nordlund, a spokeswoman for the Centers for Disease Control and Prevention.

Providing Tpoxx only as an investigational drug “ensures we have data from patients who use this drug,” she said. “This will ultimately help us understand who will benefit most, what the true benefits are and potential risks there might be.”

The restrictions on tecovirimat were even more complicated at the beginning of the outbreak, and — after much complaining from doctors — the C.D.C. loosened some of the rules. But the system remains cumbersome.

Physicians who want to prescribe the drug must first sign up to become investigators in a clinical trial, sending in résumés and informed consent forms signed by monkeypox patients — a process that is “labor intensive and virtually impossible” for most doctors, said Lynda Dee, the executive director of AIDS Action Baltimore.

“If this wasn’t such a dire emergency, it would make a very good bureaucratic joke,” Ms. Dee said. “Unfortunately, the joke is once again on the gay community.”

The rules are so complex that some patients have needed to educate their doctors on the process.

Adam Thompson, a 38-year-old cook in Atlanta, first developed a headache and body aches on July 17, and two days later had lesions on his face and rectum.

The nurse practitioner he saw had no idea how to treat him, Mr. Thompson said. Based on a friend’s experiences, he convinced her to prescribe hydrocortisone suppositories and gabapentin, a medication used to treat nerve pain.

They did not help. The nurse practitioner had heard of tecovirimat, but she told him it would take hours of paperwork to obtain.

When Mr. Thompson said he wanted her to note in his chart that she was unwilling to prescribe the drug for him, she told him the doctor would need to decide. The doctor finally called him on Sunday, July 31, nearly two weeks after he first reached out.

“She was like, ‘I’ve contacted the C.D.C., I’ve contacted the health department. I’ve contacted multiple doctors in different states, I’ve contacted multiple pharmacists in different states,’” he said.

By then, it didn’t matter. His lesions were healing, the pain had subsided and he was on the mend.

Dr. Stacy Lane, the founder and medical director of a network of seven clinics in Pennsylvania and Ohio serving the L.G.B.T.Q. population, said many of her monkeypox patients had been turned away by three or four doctors who could not deal with the tortuous federal rules regarding tecovirimat.

In early July, Dr. Lane saw a patient with eye lesions distinctive of monkeypox infection, which can lead to blindness. She tried to acquire tecovirimat, but the Pennsylvania health department insisted the patient get an eye exam first.

It was a Friday afternoon, and Dr. Lane didn’t want to have the patient wait in a crowded emergency room, so she scrambled to find an ophthalmologist instead of waiting to have the exam done “in a very controlled fashion at an outpatient office” the following Monday.

Pennsylvania has since dropped the requirement for a diagnosis, but Ohio has not.

“This doesn’t need to be held back the way it’s being held back,” Dr. Lane said of tecovirimat. “It would be ideal if we can get this Tpoxx treatment at the local pharmacies just like we can get anything else, especially as this thing continues to explode.”

Dr. Lane and others said they understood that there were still questions about the drug’s safety and effectiveness in people, but noted that it had already been shown to be safe in people and had been approved by the F.D.A.

“If a drug is already F.D.A.-approved, any physician can prescribe it as off-label because F.D.A. is not permitted to regulate the practice of medicine,” said Dr. Jay Varma, the director of the Cornell Center for Pandemic Prevention and Response.

“It is a C.D.C. policy choice to avoid releasing or recommending a drug off-label,” he added.

Many patients and doctors, including Dr. Lane, have reported that tecovirimat seems to melt away skin lesions within 24 hours. No serious adverse events have been reported.

Given the known and emerging evidence of the drug’s effectiveness in patients and the urgency of the outbreak, experts say there is little rationale for restricting access.

“I understand that there needs to be a lot more data-gathering and post-marketing surveillance and everything else,” said Dr. James Lawler, a director of the University of Nebraska’s Global Center for Health Security. “But you can do that in a way that doesn’t create barriers.”