Arizona on Tuesday became the latest state to approve a law providing terminally ill patients with greater access to unproven medical treatments, following in the footsteps of four states enacting similar measures this year.

Arizona’s new law marks the first time a “right to try” measure has been approved by ballot initiative – and it succeeded convincingly – after Colorado, Louisiana, Missouri and Michigan passed such laws in the past six months.

These laws are drawing comparisons with the 2013 movie “Dallas Buyers Club,” in which Matthew McConaughey portrays an AIDS patient in the mid-1980s who smuggles in unregulated pharmaceutical drugs across the Mexican border.

The laws are supposed to open access to drugs that have passed through the first stage of clinical trials and are part of ongoing trials. They have been backed by families of sick patients, who say that the Food and Drug Administration’s approval process for experimental treatments, despite having a 99 percent approval rate, is too cumbersome.

Under the new state laws, patients need only approval from the drug company and a prescription.

Critics of the right-to-try laws say these unproven treatments could hurt patients and complicate the drug-development process.

Further, the drugmakers do not have to provide these treatments, and there are reasons they might not want to, including liability concerns and a lack of supply early in a drug’s development. And insurers do not have to cover the drugs.

The FDA has not formally weighed in on the new laws, although agency officials have expressed concern.