The U.S. state of Arkansas has put three people to death in less than a week and another execution is planned for Thursday. Two of the prisoners were executed Monday the first double execution to be carried out in the southern U.S. state in 17 years. Officials in Arkansas recently announced plans to execute eight inmates over the course of four days by the end of April. Four of the planned executions have been blocked by legal action. The reason for so many executions in a short time is the state is running out of a drug used to carry out death sentences. The shelf life of the drug, called midazolam, is set to end at the end of April. Midazolam is one of three drugs used in a combination to carry out lethal injections in Arkansas. The drug is usually used by doctors to relax people and treat anxiety. In executions, it is used for the same purpose and is the first drug administered. The second drug, pancuronium bromide, is used to paralyze the body and stop breathing, while a third, potassium chloride, is given to stop the heart. State officials have said it is unclear when they would be able to replace the current supply of the drug for future executions.