LEWISTON, Maine — Maine patients, doctors and pharmacists are dealing with another drug shortage, this one an antibiotic to treat Lyme disease, the MRSA infection, pneumonia and other illnesses.

The shortage has become such a concern nationwide that U.S. Sen Susan Collins, R-Maine, and U.S. Sen. Amy Klobuchar, D-Minn., have asked the Food and Drug Administration to take action.

“According to our state epidemiologist, the number of Maine residents diagnosed with Lyme disease continues to increase each year,” Collins said in a statement released Friday. “The antibiotic Doxycycline is critically important for treating these patients, and it’s imperative that the FDA do all it can to help alleviate this shortage.”

Doxycycline is an antibiotic that can be given orally or intravenously. It is used to treat a host of conditions, including acne, rosacea, chlamydia, some types of pneumonia, the difficult-to-treat infection MRSA and Lyme disease.

The shortage began earlier this year. According to the FDA’s website, four companies deal with the drug. One says manufacturing delays have made its supply largely unavailable. Another says increased demand has limited its supply and it is providing the medication to current contracted customers only.

Officials with the Maine Center for Disease Control and Prevention has been monitoring the situation in Maine for about a month.

“We’ve had availability, but the price is going up and that’s obviously a concern, too,” state epidemiologist Stephen Sears said. “And, sooner or later, if it’s getting to be short nationally, it’s going to get short here, just as other drugs have.”

He said the department has heard Doxycycline’s price is now five to 10 times higher than it used to be, but he said that is hard to gauge because pharmacies all price differently and insurance companies pay differently.

In Lewiston, Central Maine Medical Center had enough Doxycycline to meet its needs. But the shortage has challenged St. Mary’s Regional Medical Center.

“Even if you can get your hands on it, it’s astronomically priced,” St. Mary’s pharmacist Vahid Rohani said.

Although it’s difficult for the hospital to get the IV form of Doxycycline, the shortage is worse for pills, Rohani said. A quick supplier search by Rohani on Friday showed that 50 capsules would cost the hospital between $197 and $270, if it could get them.

“Every now and then, we’ll get an order for Doxycycline,” he said. “We do have some, but we’re running out. We do have alternatives, thankfully, for this medication. But it would be nice to have it definitely in stock.”

Other medications are useful, depending on the illness. Azithromycin can be used for pneumonia, for example. Amoxicillin can be used for the tick-borne Lyme disease.

But while those drugs can work, Sears said, doctors like Doxycycline best for some illnesses.

“We always prefer the one we know and use first line, and for Lyme, that’s Doxycycline,” Sears said. “I applaud any effort on a national level to try and get some movement on this.”

In their letter, Collins and Klobuchar urged the FDA “to ensure you are using all resources at your disposal to alleviate this shortage as soon as possible.”

According to Collins’ office, that could include the FDA working to find alternative manufacturers, finding an alternative supply of the drug or working to import, in a limited way, from other countries.

In the meantime, Sears said, patients should be aware of the shortage and the cost increase. He said pharmacies might not be able to get Doxycycline right away and doctors might suggest taking an alternative.

Sears said state CDC officials plan to check with pharmacies again in the coming days to get an up-to-date sense of supply and shortage as the state heads into Lyme disease season.