TRENTON, N.J. >> For Bridgett Snelten, changing her health insurance meant enduring wild blood sugar swings, bouts of vomiting and weight gain.

The Sandy, Utah mother of two young girls has diabetes and has had to change health insurance plans three years in a row. Twice, new insurers wouldn’t cover Trulicity, a once-a-week injected diabetes medicine she’d been taking that helped control her blood sugar tightly. Instead, they made her return to an inexpensive, twice-a-day injected diabetes drug she and her doctor knew didn’t work for her.

Each time, blood sugar plunges caused the shakes, vomiting and other symptoms until her doctor finally persuaded the new insurer to approve Trulicity, which retails for more than $700 per month.

“It was almost a whole year of hell just trying to get on the right medication” the last time, recalls Snelten, 43. “Who are they to say more than my doctor what’s right for me?”

More and more, patients like Snelten are being caught up in efforts to rein in the cost of health care — efforts employers and patients desperately want to succeed. But the strategies also can restrict access to the newest, most expensive drugs even for those who need them.

“We are in a sense entering a two-tiered system because there are individuals who can make it happen and just write a check” for a hefty drug copayment, says cardiologist Dr. Elizabeth Klodas in Edina, Minnesota. “Others are not able.”

Some of the insurance policy provisions have long been used, but they are becoming more common, including:

— Patients generally must pay up to 30 percent of the cost of pricey drugs, not a fixed “co-pay.” That means patients who need expensive drugs can face huge bills until they hit their plan’s out-of-pocket maximum.

— Patients and doctors must get permission in advance to use some drugs, something called prior authorization, which can take weeks or months.

— Some patients, like Snelten, have to go through what’s called “step therapy.” Patients must try cheaper medicines first before they are allowed to move on to newer, costlier drugs. Sometimes, a patient’s health deteriorates in the meantime.

Starting next year, Medicare Advantage plans, which are used by about 20 million Americans over 65, will be allowed to implement step therapy provisions.

In a survey last year by the doctors’ networking site SERMO, 64 percent of the 3,050 U.S. respondents said at least once a month an insurer rejected what they’d prescribed, even after a patient had failed step therapy.

“Anything that’s a barrier decreases the chance that the doctor will prescribe it and the patient will get it,” says former American College of Cardiology president Dr. Mary Norine Walsh, head of advanced heart failure treatment at St. Vincent Heart Center in Indianapolis.

Nearly 80 percent of family doctors and specialists surveyed by the American Medical Association last year said patients “often” or “sometimes” abandon their recommended treatment if their insurer won’t cover it. Ninety-two percent said the red tape associated with getting drugs covered harms patients’ health.

Dr. Stephen Kopecky, a cardiologist who focuses on prevention at the Mayo Clinic in Rochester, Minnesota, said one recent appeal for approval for a type of new cholesterol drug went on so long that his patient had to have a stent implanted in a blood vessel before she finally got approval. He thinks the drug could have prevented the procedure.

Kopecky says another patient needing the same drug only won approval after giving her insurer 23 types of medical information, including receipts proving she’d taken inexpensive cholesterol-lowering statin pills for 10 years without enough improvement.

“It sometimes takes weeks, if not months, of submitting prescriptions, rewriting prescriptions, appealing, rebuttals,” he says.

The reason: Generic cholesterol drugs that work well for most people cost just pennies a day. The newer drugs, Repatha and Praluent, can retail for more than $14,000 a year.

“I understand insurers balking,” says Klodas. But even when they approve expensive drugs, copayments can be so high, “Patients say, ‘I can’t do that.’”

That can leave doctors with a tricky call.

“There are situations where we have to change treatment plans because of cost,” says Dr. Yousuf Zafar, a gastrointestinal cancer specialist at the Duke Cancer Institute in North Carolina. “I’ve had a handful of patients where cost is so overwhelming they opted for no treatment.”