"Not having flare-ups is a blessing. It's painful," the Lutz resident said.
But the manufacturer recently stopped production of generic gold, sending Crosby, 70, into the growing ranks of Americans affected by a national epidemic of drug shortages.
Certain antibiotics, high blood pressure medicine and muscle relaxants are all among the commonly prescribed medications that are in short supply or no longer available.
The latest is a shortage of the generic form of Adderall XR, used for attention-deficit hyperactivity disorder (ADHD) in children and adults.
Even more worrisome are shortages of injected drugs used for cancer treatment, anesthesia during surgeries and other life-saving functions.
The recent lack of a key leukemia drug temporarily left some Americans without their best option for life-saving treatment, and drew new attention to the drug supply problem. Area doctors and pharmacists watched the situation nervously, but were able to keep local patients supplied.
The shortage of generic drugs is particularly critical to people whose insurance will pay only for generics.
"Absolutely, it's a crisis," said Bona Benjamin, a pharmacist and an official with the American Society of Health-System Pharmacists.
"In 2010, I was saying it was a pending crisis, now it's here, and it has the potential to really compromise care," Benjamin said.
There are many reasons for shortages. Raw materials can be scarce. Government inspectors can shut down production because of quality concerns. Demand can suddenly outstrip supply. Manufacturers may choose not to make low-profit, low-demand medications.
Blame gets passed around. In the case of generic Adderall XR, the firms that mass produce it say they aren't getting enough supply from the maker of the brand-name version, Shire Pharmaceuticals. Shire says the U.S. Drug Enforcement Administration is restricting the drug, an amphetamine. The DEA says it's not to blame.
With highly addictive painkillers, such as OxyContin, there have been restrictions to fight illicit use, making it harder to obtain for legitimate pain patients.
Benjamin says pharmacists don't know from day to day what they will have available. "Pharmacists are at the end of their ropes. If the shortage is invisible to physicians and patients, it's because pharmacists are scrambling and exhausting all their options."
Gene Wetzstein, director of pharmacy services at H. Lee Moffitt Cancer Center in Tampa, says pharmacists have always had to cope with drug shortages, but the current situation is worse than ever.
"It's frustrating and time consuming," Wetzstein said, "but it's now a daily part of our routine, working on procuring drugs. There's a lot going on behind the scenes to make sure patient care isn't interrupted."
Area hospitals and pharmacies report that prescriptions are being filled, but not always easily.
"So far, we can get around it by contacting several suppliers, sometimes three or more, but it's a lot of extra work," said Amanda Rees, pharmacy manager at the independent West Shore Pharmacy in Tampa.
The Food and Drug Administration maintains a website that lists medically necessary products — used to treat serious illnesses — that are difficult or impossible to get. As of Wednesday there were 192 drugs on the shortage list.
The FDA has a process to allow high-demand, medically necessary drugs to be imported, as long as they meet U.S. standards, agency spokeswoman Shelly Burgess said.
Benjamin and the pharmacist association support proposed federal legislation that would require drugmakers to give the FDA advance notice when supplies may be in jeopardy or when a company decides to stop making a drug.
Currently, companies must give six months' notice before discontinuing "sole source products that are life-supporting, life-sustaining or for use in the prevention of a debilitating disease or condition.''
Expanding the requirement to other drugs "will help us to plan and implement practices to prevent or minimize shortages," she said.
Dan Buffington, a Tampa pharmacologist, also favors starting a national drug inventory system similar to the one used by blood banks to prevent regional blood shortages.
"We need to apply that principle to medications,'' he said. "It's imperative so medications that are in surplus can be exchanged or shared with pharmacies to prevent patients going untreated."
Crosby called all over town before finding his medication at a Brandon pharmacy, and bought all he could — enough to get through the summer. The manufacturer, Taylor Pharmaceuticals, has not set a date to resume production.
Information from Times wires was used in this report. Irene Maher can be reached at firstname.lastname@example.org.