The American Pharmacists Assn. on Monday adopted a policy that discourages its members from providing death penalty drugs.
The new guidelines could make it tough for death penalty states such as Texas that have been looking at made-to-order execution drugs from compounding pharmacies as the answer to a nationwide shortage of execution drugs.
The association's governing body approved the policy at a meeting in San Diego.
The group lacks the legal authority to bar compounding pharmacies from selling execution drugs. But its policies set ethical standards followed by pharmacists, just as the American Medical Assn. does for doctors.
Prisons have had to buy made-to-order execution drugs from compounding pharmacies in recent years because the pharmaceutical companies they used to buy their drugs from refuse to sell them for use in lethal injections after coming under pressure from death penalty opponents.
But now the compounded version is also difficult to come by, with most pharmacists reluctant to expose themselves to possible harassment by people who oppose the death penalty.
Texas' prison agency scrambled this month to find a supplier to replenish its inventory, then found a supply from a compounded pharmacy it would not identify. Also this month, an execution in Georgia was postponed when prison authorities questioned the appearance of the compounded pentobarbital they planned to use.
After a troubling use of a two-drug method last year, Ohio said it would use compounded versions of either pentobarbital or sodium thiopental in the future, though it doesn't have supplies of either drug and hasn't said how it will obtain them. All executions scheduled this year were pushed to 2016 to give the state more time to find the drugs.
Others states are turning to alternative methods.