People may be inspired to quit smoking cigarettes soon after a heart attack, but new research suggests many don't take advantage of drugs that could help them.

Only 7% of smokers picked up a prescription for a smoking cessation drug during the 90 days following their heart attacks, researchers found.

"These medications are being underused," said lead author Dr Neha Pagidipati, of Duke University in Durham, North Carolina. "Now we need to understand why."

Pagidipati and colleagues noted in JAMA Cardiology online July 19 that despite the increased risk, just over half of people stop smoking in the year after a heart attack.

Along with nicotine replacement therapies like gum and patches, people trying to quit cigarettes can use medications such as bupropion and varenicline.

"What we didn’t know is how often are these medication being used in patients who recently had a heart attack," Pagidipati told Reuters Health.

For the new study, researchers analysed data on 9,193 smokers who had a heart attack between 2007 and 2013. All were at least 65 years old.

Overall, 97% patients were counselled during their hospital stay about smoking cessation, but only 7% ended up picking up medications to help achieve that goal within 90 days.

"It suggests somewhere in there is a break in the link," said Pagidipati. "Now we need to go back and figure out where is the problem."

Of those who did pick up a prescription, about 53% used varenicline and about 47% used bupropion. But only about 37% of those taking bupropion and only about 20% of those taking varenicline used them for the recommended 12 weeks.

About half of the patients using bupropion took the drug for less than 6.2 weeks. Similarly, about half of the patients on varenicline used it for less than 4.3 weeks.

Pagidipati said it's not clear whether doctors are not prescribing the medications or patients aren't filling their prescriptions due to fear of side effects or cost.