Credit cards offered by banks including Wells Fargo & Co. and Synchrony Financial intended to cover expensive health-care services may be causing unnecessary financial pain for consumers, said a group of US senators, who cited potentially deceptive promotions.

Struggling patients are “lured” in by deferred-interest offers that allow the lenders to profit off of consumers dealing with high health-care costs, Senators Elizabeth Warren and Edward Markey, both Democrats from Massachusetts, said in a letter to Wells Fargo and Synchrony. Senator Bernie Sanders, an independent from Vermont, along with Democrats Chris Murphy of Connecticut and Sherrod Brown of Ohio, also signed the letter requesting information from the lenders by Jan. 12.

“Patients – often under duress because of concerns about their medical care – are being pushed into and then locked into medical credit cards despite the availability of alternative payment options that might be more beneficial and offer lower interest rates,” the lawmakers said in the letter.

Wells Fargo offers a medical credit card called Health Advantage, and Synchrony offers one called CareCredit.

“CareCredit works hard to ensure our products are offered responsibly and with clear, simple, transparent terms so consumers can make well-informed decisions about financing their care,” Synchrony said in an emailed statement. The Stamford, Connecticut-based lender is “working with the senators and other public officials on gathering information in response to their request.”

Wells Fargo, based in San Francisco, didn’t immediately respond to a request for comment on the letter.

This article was provided by Bloomberg News.