Long-term disruptions to propofol production have veterinarians across the country scrambling to cope with a shortage of the widely used anesthetic.

While the shortfall has impacted human and animal medicine, supply problems appear to be particularly acute for the veterinary community. Overall availability of the drug is expected to improve in September as the one remaining maker of propofol for the U.S. market continues to expand production, but it is not clear how long it will be until supplies reach veterinary clinics.

New supplies of PropoFlo and Rapinovet — the two name-brand propofol products marketed for veterinary use — have not been manufactured for most of 2010. Though veterinarians can and do use generic and name-brand propofol marketed for human medical use, veterinary drug distributors appear to be having difficulty obtaining supplies of those products.

Dr. Scott Kepner, who runs Riverview Animal Hospital in Vancouver, Wash., said his clinic has been without propofol for more than a month, forcing him to switch to a combination of ketamine and valium for surgeries. Kepner said he’s particularly frustrated because his friends and acquaintances in human medicine have been able to get supplies refilled.

“On the veterinary side, all my colleagues have run out,” Kepner said. “We've called every resource possible” in the resupply search, including pharmacies and a number of drug distributors, he said.

While propofol is sold in the United States under a number of different labels, it is made by only two companies: APP Pharmaceuticals, a subsidiary of Germany-based Fresenius Kabi AG; and Hospira Inc., of Lake Forest, Ill. Hospira’s production has been suspended since November 2009 — except for a brief run in March and April — due to contamination that forced multiple recalls. Hospira is working to fix the production-line problems that led to the contamination. The company has not said when it expects production to resume.

A third company, Israel-based Teva Pharmaceutical Industries Ltd., was a major supplier of propofol to the U.S. market until recently. Bacterial contamination forced several recalls of the company’s propofol starting in July 2009, and in May 2010 Teva announced it would no longer make the drug, saying it was unprofitable.

According to the U.S. Food and Drug Administration (FDA), two propofol products are approved expressly for use in dogs and cats: Rapinovet and PropoFlo.

Rapinovet, formerly marketed by Schering-Plough, has been a Teva Animal Health brand since April 2010, according to the FDA. It is not clear if Teva plans to buy propofol from another manufacturer and sell it under the Rapinovet label. Teva officials could not immediately be reached for comment.

PropoFlo has been made by Hospira. A spokeswoman for Abbott said the company still has a small amount of PropoFlo in stock and has been filling some orders. Hospira also has some stock remaining of generic propofol (labeled for use in humans) which it is releasing slowly, according to a company spokesman.

The production shutdowns for Rapinovet and PropoFlo didn’t hit veterinarians immediately because manufacturers and distributors could fill orders from existing stocks for several months.

APP is currently selling three propofol products — Diprivan, Propoven and a generic propofol. The company has expanded propofol production in response to the nationwide shortage but is not yet able to meet demand, according to an update Tuesday from the American Society of Health-System Pharmacists, which monitors drug availability.

The APP and Hospira propofol preparations on the U.S. market are all 1 percent propofol injectable emulsions, the same as PropoFlo and Rapinovet.

Cindy Reilly, director of practice development at the health-system pharmacists’ group, said her members have reported improved availability recently, leading to hope that the shortages — which human hospitals have been dealing with since last fall — are nearing an end.

But, she cautioned, “It's not the first time we've thought that.”

It is not clear whether APP and Hospira are restricting their sales to human-medical channels only. Representatives for both companies noted that their propofol products are not labeled for use in animals. But the representatives could not provide information immediately about whether their propofol products are being sold to veterinary drug distributors.

Reilly said there are no regulations that would require companies to supply propofol preferentially to human hospitals over veterinary clinics. But in practice, she said, large hospital groups that buy direct from producers may receive supplies of the drug ahead of individual veterinary clinics.

That hunch prompted Dr. Terri Sears, who owns TenderCare Veterinary Center in Fishersville, Va., to contact a local hospital when her propofol supply ran out earlier this month.

“They wouldn’t sell any to us,” she said.

Like Kepner, the veterinarian who practices in Washington, Sears has switched to administering valium and ketamine to her surgical patients. She would rather use propofol, she said, because ketamine can cause problems for patients with heart conditions. Compared to propofol, ketamine generally yields longer wake-up times after surgery and tends to leave patients more disoriented, Sears and other veterinarians said.

At least eight recent message board discussions on the Veterinary Information Network, an online community for the profession, have focused on the propofol shortage. Several of those conversations deal with the range of propofol alternatives available to veterinarians, including etomidate, Telazol and Dexdomitor, an analgesic and sedative.