The Green Berets and other members of the U.S. Army’s elite commandos will no longer be prescribed the anti-malarial drug, mefloquine, which has been linked to permanent brain damage in the past.

The decision from the Special Forces’ top physician comes less than two months after the Food and Drug Administration (FDA) slapped its “black box” warning — the agency’s strongest precautionary label — onto the drug.

Originally developed by Army doctors in the 1970s, mefloquine was the first line of defense against the mosquito-borne disease for decades. Millions of travelers along with military men have taken the drug to prevent malaria, a disease which still kills 660,000 people annually, according to the World Health Organization.

The FDA toughened its warning for the drug due to a slate of neurological side effects that have been connected to its use. These include dizziness, loss of balance, and ringing in the ears, as well as psychiatric symptoms like anxiety, depression, and hallucinations.

“Neurologic side effects can occur at any time during drug use, and can last for months to years after the drug is stopped or can be permanent,” the FDA wrote in its July 29 announcement.

The Army’s use of mefloquine has declined in recent years as alternative medications have been developed and as more and more veterans have blamed the drug for malingering psychological deficits following their tours. From 2008 to 2011, the Army slashed prescriptions by almost 75 percent. Roughly 2,000 prescriptions have been issued this year, compared to over 20,000 over the same time frame in 2009.

The prescription ban from Surgeon General's Office of the Army Special Operations Command applies to approximately 25,000 Green Berets, Army Rangers, and Civil Affairs and Psychological Operations soldiers. Commanders and medicial workers have also been ordered, according to the Associated Press, to determine if any of their troops have suffered from the drug’s side effects, but have been mistakenly told that they have posttraumatic stress disorder or other psychological conditions.

"What this is is a wake-up call telling troops, `Look, you've been misinformed,'" Remington Nevin, a former Army physician, told the Associated Press.