The drug company Pfizer has announced it will no longer sell drugs for use in lethal injections because it objects to their use in executions.

"Pfizer makes its products to enhance and save the lives of the patients we serve. Consistent with these values, Pfizer strongly objects to the use of its products as lethal injections for capital punishment," the company said in an April 2016 policy position paper.

The company is enforcing a distribution restriction for seven drugs that have been a part of lethal injection protocols or have considered for such protocols.

The new policy means there is no remaining open-market source of lethal injection drugs in the U.S., the New York Times reports. Over 20 American and European companies have adopted restrictions on lethal injection drug provision, sometimes as a result of advocacy from death penalty opponents. The European Union has banned the export of the drugs used in lethal injections.

The drugs affected by the Pfizer policy change include pancuronium bromide, potassium chloride, propofol, midazolam, hydromorphone, rocuronium bromide and vecuronium bromide.

"Pfizer offers these products because they save or improve lives, and markets them solely for use as indicated in the product labeling," the company said.

The drugs will be sold to wholesalers, distributors and direct purchasers on condition that they not resell them to correctional institutions for use in lethal injections. Government purchasers may not provide the drugs to any other party.

The company said it will monitor the distribution of these drugs and act upon any findings of non-compliance.

Drug production bottlenecks as well as opposition from death penalty opponents have limited the availability of lethal injection drugs.

New drug combinations have been faulted for several high-profile botched executions, in which the condemned inmates took a prolonged period to die.

There are 32 U.S. states that allow the death penalty. Some states have adopted the electric chair, firing squad or gas chamber as an alternative to lethal injection.