SAN DIEGO

At least 504 terminally ill Californians have requested a prescription for life-ending drugs since a state law allowing doctor-assisted deaths went into effect in June 2016, marking the first publicly released data on how the practice is playing out in the nation’s most populous state.

The number released Thursday represents only those who have contacted Compassion & Choices, an advocacy group that provides information on the process. The organization believes the overall figure to be much higher. State officials have not released data yet.

How the new law is used in California could provide a window into what would happen if the practice spreads nationwide. Some see providing the choice to the dying as a logical evolution in a medical care system advanced in helping people live longer but limited in preventing slow, painful deaths.

Critics say they are concerned that the option will lead to hasty decisions, misdiagnosis and waning support for palliative care, in which dying people can be sedated to relieve suffering.

Betsy Davis was among the first Californians to use the law. The 41-year-old artist with ALS, or Lou Gehrig’s disease, held a party to say goodbye to her family and friends before taking the lethal dose of drugs July 24.

Her sister, Kelly Davis, said the family has no regrets about her decision.