For seniors living on fixed incomes, especially those with multiple chronic conditions, the cost of medication can sometimes be too much to bear.

William J. Hager, 86, told police that he shot his wife of more than 50 years in the head while she slept because she was in pain and the cost of her medications had become too much of a burden.

While this is an extreme example, the incident early last week in Florida highlights the pressure faced by some older people to pay for expensive prescription drugs while on a fixed income.

“It’s a real problem. Particularly when you have people that worked all their lives and now they’re the ones with fixed incomes and they’re being barraged with medications that are very expensive,” Jim Giordano, RPh., a pharmacist with West Grange Pharmacy in Trenton, Michigan, told Healthline.

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According to the Kaiser Family Foundation, people enrolled in Medicare in 2010 spent on average around $300 per year on prescription drugs.

That’s on top of the roughly $4,400 per year they paid for health insurance premiums and other healthcare services such as long-term care and visits to the doctor.

Some seniors, though, may pay much more for their medications.

“Some of the new drugs that are coming out — that are not covered by most of these plans — are very expensive,” Gail Jensen Summers, Ph.D., an economist at Wayne State University, told Healthline.

People enrolled in the Medicare Part D drug insurance plan who are taking speciality drugs to treat hepatitis C, multiple sclerosis, rheumatoid arthritis, or cancer pay between $4,000 and $12,000 out-of-pocket annually.

That’s for one drug alone.

And even generic drugs don’t always offer cost relief for older adults.

“The price of generic drugs are really going through the roof,” said Giordano. “For every cheap generic drug, there are probably five really expensive ones.”

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When the cost of their medications becomes too much, older people may try to make their prescriptions last longer.

“They’ll skip their medications. They’ll take something every other day, instead of every day, or they’ll break the pills in half,” said Giordano.

This is what researchers call cost-related nonadherence. Estimates of how extensive it is among seniors vary.

One study, published earlier this year in the Journal of Pharmaceutical Health Services Research, found that 2.4 percent of seniors reported skipping a medication in the past 12 months due to the high cost. When researchers looked at the past 24 months, nonadherence increased to 7 percent.

Some groups are affected more by high drug prices.

“We found that people who were in poor health were much more likely to report cost-related nonadherence,” said Jensen Summers, an author on that paper.

“We also found higher prevalence of cost-related nonadherence among seniors with two or more chronic conditions,” she said. “That’s because when you’re taking more medications, you’re more likely to have trouble paying for medication.”

Stretching out your medication can backfire, especially for seniors who are still working. Skipping drug doses can worsen their chronic conditions, which makes it harder to work and afford proper health insurance.

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When Medicare Part D was introduced in January 2006, it was meant to address some of these concerns.

In some ways it worked.

A 2014 study in Health Affairs found that the affordability of drugs for people on Medicare increased between 2007 and 2009.

This mirrors what Jensen Summers found in her own research, which was done before Part D was introduced — people with drug insurance were less likely to report skipping medication.

But that’s not the end of the story.

“I think Part D has gone a long way in helping seniors, but it’s not a panacea,” said Jensen Summers. “I think seniors may still face cost-related nonadherence and they may not be getting everything they want or everything that can help them.”

The 2014 Health Affairsstudy also found that among Medicare beneficiaries with four or more chronic conditions, cost-related nonadherence rose to 17 percent in 2011.

Among the sickest elderly, the number giving up basic needs to pay for their medications rose to 10 percent in 2011.

These backslides may be related to the recession in the United States between 2007 and 2009. But researchers point to other factors, including Social Security not keeping up with inflation and Part D drug plans charging more for copayments or deductibles.

“Ten or 15 years ago we had $5 and $10 copays,” said Giordano. “Now you have $40 and $60 copays, or $100 copays.”

There’s also the problem of Part D coverage gaps — or donut holes. If people use up their drug benefits early on, they end up paying higher prices for the rest of the year.

And even when Part D plans work well, people still need to choose the plan that covers the medications they’re currently taking or will be taking later on.

“I don’t think it’s that easy for some seniors,” said Jensen Summers. “They may have trouble choosing a plan. They may be overwhelmed with all the choices out there. And if they have problems with cognition, which are not uncommon, then it can be a real challenge.”