CVS Health Corp. and Walmart Inc. will stop filling prescriptions for controlled substances ordered by clinicians working for Cerebral Inc. and Done Health, the broadest curbs yet by major pharmacies against the telehealth companies following scrutiny of their prescription practices.

A CVS CVS, +0.73% spokesman confirmed the change, citing concerns with the two companies following a review it conducted. Cerebral had earlier disclosed the change to The Wall Street Journal. A Walmart WMT, -0.61% spokeswoman said the retail giant is taking steps to no longer fill those prescriptions but didn’t elaborate on why it made the decision.