Disability-rights advocates fought hard last year against passage of the act and continue to voice concern.
Golden said it's impossible to know if a depressed patient went to many doctors who all denied the request for lethal medication before finding one who agreed to write the prescription.
"We are looking ahead at measures to protect people from abuse," said Marilyn Golden, senior policy analyst with the Disability Rights Education & Defense Fund, "and to explore and inform doctors, nurses and pharmacists that they don't have to participate."
As written, the law requires two doctors to agree that a patient has six months or less to live before prescribing the drugs. Patients must be able to swallow the medication themselves and must affirm in writing 48 hours before taking the medication that they will do so.
California is the fifth state to permit this end of life option. It joins Vermont, Oregon, Washington and Montana.
Across the state, some patients with advanced cancer welcomed the news.
"It gives me a great peace of mind to know that I will not be forced to die slowly and painfully," said Elizabeth Wallner, in a release from Compassion & Choices, an advocacy group. Wallner, 52, of Sacramento, is a single mother with stage IV colon cancer that has spread to her liver and lungs.
"It gives great comfort to know that the agonizingly traumatic image of me suffering will not be my family's last memory of me," she said.
Sen. Monning expressed his gratitude to people who worked for passage of the law, some in their final days:
- Brittany Maynard, an Orange County woman with brain cancer who moved to Oregon to take advantage of aid-in-dying there. Before she died, she recorded a video that was shown during hearings on the "End of Life Option Act" in Sacramento
- Jennifer Glass, of San Mateo, who helped to launch the campaign in 2014, then died of lung cancer last year
- Christy O'Donnell, 47, of Los Angeles, who died of lung cancer last month