“A drug’s list price is not the primary factor in determining patient affordability and access,” Nancy Retzlaff, Turing’s chief commercial officer, said in a statement. “A reduction in Daraprim’s list price would not translate into a benefit to patients.”

The company pledged that no patient needing Daraprim would ever be denied access.

Some patient advocates and infectious disease doctors said the actions were not enough. Although most patients are initially treated in the hospital, they said, that typically is for several days, and then patients have to take the drug for weeks or months after they leave.

“This is, as the saying goes, nothing more than lipstick on a pig,” Tim Horn, H.I.V. project director for the AIDS research and policy organization Treatment Action Group, said in an email.

Daraprim, which has been on the market since 1953, is the preferred treatment for toxoplasmosis, a parasitic infection that can cause severe brain damage in babies, people with AIDS and others with compromised immune systems. Turing, a start-up based in New York, acquired the drug in August for $55 million and immediately raised the price about fiftyfold, to $750 per tablet from $13.50.

Besides saying it would cut the price to some hospitals, Turing said on Tuesday that it would come out with a bottle containing 30 pills instead of the current 100, making it less costly for hospitals to stock the drug. It also said it would offer sample starter kits at no cost to community doctors so they would have the drug on hand to begin immediate treatment in an emergency.