Patients around the nation are being victimized by medical credit cards that can lead to financial calamity. These cards, issued by specialty finance companies as well as commercial banks, carry exorbitant interest rates after an initial period of zero interest expires — with heavy penalties for late payments. They are often pushed on patients with modest incomes by health care providers who want to make sure that they get paid, even if some of their patients end up with huge credit card bills they can’t afford. Unless strong regulatory action is taken to curb the abuses, financial companies will continue to gouge consumers at their most vulnerable moments, when they are in pain and need medical attention.

Doctors and dentists whose offices arrange for these credit cards say these kinds of loans help patients pay for the care and procedures they need. But it’s hard to imagine a situation in which a consumer is more susceptible to financial coercion by a provider with a conflict of interest.

Patients typically sign up for these credit cards to pay for services like dentistry and devices like hearing aids that are not covered by Medicare or are only partially paid for by private insurance. The doctors get a good deal because they get paid promptly, while patients are often unaware of the harsh terms of this kind of credit until they get the bill.

As Jessica Silver-Greenberg reported in The Times last week, the scope of this problem is growing, as more patients sign up for cards issued through practitioners’ offices by companies like iCare Financial of Atlanta; CareCredit, a unit of General Electric; and banks like Wells Fargo and Citibank. Some patients thought they were agreeing to an in-house payment plan with their dentist’s office when in fact they were taking out a high-cost credit card with a financial institution. Others didn’t realize that the interest rate could skyrocket on bills not paid in full. Some companies don’t check a patient’s credit history or impose upfront charges on the patient, which makes it easy for people to take on extra debt they can’t afford.