The Food and Drug Administration on Wednesday reported a shortage of an injectable form of penicillin, an antibiotic used to treat syphilis and other bacterial infections like strep throat.
The drug joins a growing list of medications facing supply shortages in the U.S. Liquid amoxicillin, another antibiotic used to treat strep, has been in short supply since October, according to the FDA.
The form of penicillin affected, called penicillin G benzathine, is the preferred drug for syphilis, because it can be used in adults, children and pregnant people. It's often administered in outpatient clinics or urgent care settings. Dosages for both children and adults are in short supply, according to the FDA.
"The nice part about penicillin G benzathine is that you can give it to a pregnant mother and if she has syphilis, it will also treat the baby," said Dr. Jeremy Cauwels, the chief physician at Sanford Health, a medical system in Minnesota and North and South Dakota. He said pharmacists in his network have been dealing with a limited supply of penicillin since the winter.
Syphilis cases in the U.S. reached a 70-year high in 2021, the last year for which data is available, according to the Centers for Disease Control and Prevention. The sexually transmitted infection can result in organ damage or death if left untreated.
The FDA attributed the penicillin shortage to increased demand. Pfizer, the sole supplier of that form of penicillin in the U.S., pointed to the amoxicillin shortage as the main issue, because it prompted doctors to recommend penicillin instead. The rise in syphilis cases most likely further accelerated demand, the company said.
The amoxicillin shortage arose during a surge of respiratory virus infections over the fall and winter, when the antibiotic was prescribed for secondary bacterial infections resulting from Covid, flu or respiratory syncytial virus.
Amoxicillin has also been used to treat a rise in severe strep cases dating to the fall. In November, the American Academy of Pediatrics recommended penicillin G benzathine as an alternative to amoxicillin for strep throat patients.
Strep throat case numbers remain elevated. The CDC said last week that unpublished data from its national surveillance program showed a five-year high in emergency department visits for regular strep infections in February and March.
Pfizer said it has been delivering more of its injectable penicillin to the market than ever before but still can’t keep up with demand. The FDA said on its website that supply issues are expected to resolve sometime from October to December.
The American Society of Health-System Pharmacists has reported an additional shortage of another form of penicillin, penicillin G procaine, which doesn't last as long in the body or cross the placental barrier. But Michael Ganio, the society's senior director of pharmacy practice and quality, said "benzathine is probably a little bit more of a challenging shortage, because it is the drug of choice."
Overall, the Covid pandemic seems to have worsened drug supply issues, Cauwels said.
New medication shortages increased by nearly 30% from 2021 to 2022, according to a March report from Democrats on the Senate Homeland Security and Governmental Affairs Committee. The reasons, it said, include a surge in demand for certain drugs, overreliance on foreign suppliers and manufacturers’ moving overseas.
The U.S. is seven months into a shortage of Adderall, a medication for attention-deficit/hyperactivity disorder. Four cancer drugs, including two common forms of chemotherapy, are under shortage as well, according to the FDA.
Injectable medications are more than twice as likely to experience shortages compared to other forms, such as oral or topical drugs, the Senate committee report said.
Cauwels said his health system doesn't expect to get additional penicillin supply until the fall, although it is likely to have enough until then. Its amoxicillin supply is also limited, he added, but it’s getting a steady allocation based on what it has used in previous years.
He added that although there are alternatives to Pfizer's penicillin drug for treating syphilis, other antibiotics come with more side effects.
The injectable penicillin became the go-to, he said, because "we know it always works and we know it’s easy to administer."