BOSTON – Some antimicrobial agents are in such short supply that a majority of physicians surveyed reported having to switch to a more toxic or expensive alternative, and more than half said that the shortage adversely affected patient care, reported investigators at the annual meeting of the Infectious Diseases Society of America.
Among 634 members of the IDSA's Emerging Infections Network, 78% said they had had to modify their antimicrobial choice because of a shortage of the preferred agent within the past 2 years, and 52% reported that the shortage had adversely affected patient care or outcomes, said Dr. Philip M. Polgreen of the University of Iowa in Iowa City.
Fully 70% learned of the shortage from the pharmacy only after they had prescribed the drug, and only 24% said they found out about the shortage from an official source such at the Food and Drug Administration's Drug Shortages website.
"Some of the adverse effects that were reported were exposing a patient to a more toxic drug, exposing them to a much more expensive drug, exposing them to a drug with a much broader spectrum than was needed, and in some cases the physician reported that a patient had to stay longer in the hospital or had a failure of therapy," Dr. Polgreen said at a briefing on Oct. 20.
In a subgroup of 250 respondents, 28% said that patients incurred long-term morbidity from inadequate treatment.
The drugs that are reported to be in short supply tend to be those recommended for less common infections, and their availability may be subject to supply chain issues or local shortages. Although the study was not designed to examine reasons for shortages, several of the agents come from a single supplier, and the shortage of one agent may lead to overuse and subsequent shortage of another, Dr. Polgreen suggested.
The drugs reported most frequently to be unavailable or in short supply include the intravenous formulation of trimethoprim/sulfamethoxazole (Bactrim), amikacin (Amikin), aztreonam (Azactam), foscarnet (Foscavir), and penicillin G.
Other agents in short supply include oseltamivir (Tamiflu) oral suspension, and acyclovir (Zovirax) tablets, as well as injectable biologic agents and vaccines, including intravenous immune globulin, live zoster vaccine, yellow fever vaccine, and inactivated influenza vaccine.
The investigators sent a web-based survey with nine questions to all 1,350 members of the IDSA-EIN, a sentinel network of physicians. They received a total of 634 responses (47% response rate).
Dr. Polgreen acknowledged that that study was limited by self-reporting with no verification and by possible response bias, with members who had encountered a drug shortage being more likely to respond.
He said that physicians need more effective ways of learning about impending or current shortages and about acceptable alternatives to first-line agents. Such efforts are particularly important in light of the fact that there are very few antimicrobial agents in the drug development pipeline, he said.
In a separate presentation, Dr. Helen Boucher, of Tufts Medical Center, Boston, and her colleagues reported that drug companies aren't exactly scrambling to solve the problem of antimicrobial resistance to existing agents.
The researchers identified nine drugs in clinical development for parenteral use against gram-negative bacilli. Of these agents, only two have novel mechanism of action, and none is being studied for efficacy against community-acquired bacterial pneumonia, or hospital- or ventilator-associated pneumonia.
The number of new antibiotics approved for marketing in the United States annually continues to decline, and major pharmaceutical companies – many of which pioneered antimicrobial drug development – are continually slackening both the pace and the quantity of antimicrobial agent development.
"We all know that with antibiotics, attrition happens, so that even in the later stages of development, we can’t count on getting all or even a majority of these compounds to market. Further, and very importantly, none of these drugs is available today, and our patients need new drugs now," Boucher added.
Dr. Polgreen's study was supported by the Centers for Disease Control and Prevention. He reported having no conflicts of interest. Dr. Boucher's study was funded by the participating institutions. She disclosed serving on an adjudication committee for Merck and as a consultant to Merck, Wyeth/Pfizer, Durata, and PolyMedix.